CN110032474A - A kind of snapshot, which occupies, holds method for determination of amount, system and associated component - Google Patents

Abstract

The present application discloses a method for determining the occupied capacity of a snapshot. The determining method includes, when an overwrite instruction is received, determining a target data object corresponding to the overwrite instruction in the original logical volume, and creating a read-only snapshot volume with a target data object corresponding to the overwrite instruction. A clone object with the same content of the target data object; perform a write operation on the target data object according to the overwrite instruction to obtain a new logical volume; write the logical volume mirror data corresponding to the new logical volume in the explicit read-only snapshot volume, and execute the write operation according to the The content in the target data object after that updates the hidden clone snapshot volume; the snapshot occupied capacity is determined according to the number of objects in the read-only snapshot volume, the explicit read-only snapshot volume, and the hidden clone snapshot volume. The present application can accurately describe the occupied capacity of snapshot data and improve the storage performance of distributed block storage services. The present application also discloses a system for determining the occupied capacity of a snapshot, a computer-readable storage medium, and an electronic device, which have the above beneficial effects.

Description

A method, system and related components for determining the capacity occupied by snapshots

technical field

The present application relates to the field of computer technologies, and in particular, to a method, a system, a computer-readable storage medium, and an electronic device for determining the occupied capacity of a snapshot.

Background technique

In current distributed block storage, data is stored in data objects in the form of KV pairs. After creating a snapshot for a logical volume, overwriting the original logical volume will trigger copy-on-write, that is, copy a "snapshot object" of the object to be written to the original volume, and then write data to the original volume object. This process is COW. When performing a snapshot rollback, just overwrite the original object with the snapshot object corresponding to the snapshot.

In current distributed block storage, snapshot attributes include the size of the original logical volume and the used capacity of the snapshot. The used capacity of the original volume at the time of creating the snapshot is calculated from the used capacity of the snapshot. After the snapshot is created, it does not change with the reading and writing of the original volume, which does not conform to the COW principle of snapshots. In addition, the data of the writable snapshot includes the original volume image data generated by the snapshot COW and the business data newly written by the user. The used capacity of the snapshot cannot accurately describe the total occupied size of the above two kinds of data.

Therefore, how to accurately describe the occupied capacity of snapshot data and improve the storage performance of the distributed block storage service is a technical problem that needs to be solved by those skilled in the art.

SUMMARY OF THE INVENTION

The purpose of this application is to provide a method and system for determining the occupied capacity of snapshots, a computer-readable storage medium and an electronic device, which can accurately describe the occupied capacity of snapshot data and improve the storage performance of distributed block storage services.

In order to solve the above-mentioned technical problems, the present application provides a method for determining the occupied capacity of a snapshot, and the determination method includes:

When an overwrite instruction is received, determine the target data object corresponding to the overwrite instruction in the original logical volume, and create a clone object in the read-only snapshot volume that is consistent with the content of the target data object;

Perform a write operation on the target data object according to the overwrite instruction to obtain a new logical volume;

Write the logical volume mirror data corresponding to the new logical volume in the explicit read-only snapshot volume, and update the hidden clone snapshot volume according to the content in the target data object after performing the write operation;

The snapshot occupied capacity is determined according to the number of objects in the read-only snapshot volume, the explicit read-only snapshot volume, and the hidden clone snapshot volume.

Optionally, when the snapshot occupied capacity includes the read-only snapshot occupied capacity and the writable snapshot occupied capacity, according to the objects in the read-only snapshot volume, the explicit read-only snapshot volume and the hidden clone snapshot volume. The number of snapshots used to determine the occupied capacity includes:

Calculate the occupied capacity of the read-only snapshot according to the number of objects and the object size of the read-only snapshot volume;

The occupied capacity of the writable snapshot is calculated according to the number and size of objects in the explicit read-only snapshot volume and the hidden clone snapshot volume.

Optionally, before receiving the overwriting instruction, the method further includes:

When it is detected that a new data object is created in the logical volume, the state corresponding to the new data object in the object state table is set to the first state.

Optionally, after the overwrite operation is performed on the target data object of the logical volume, the method further includes:

A state in the object state table corresponding to the target data object is set as a second state.

When the snapshot occupied capacity includes the read-only snapshot occupied capacity and the writable snapshot occupied capacity, the snapshot occupied capacity is determined according to the number of objects in the read-only snapshot volume, the explicit read-only snapshot volume and the hidden clone snapshot volume Capacity includes:

Determine the number of data objects in the second state in the object state table, determine the number of objects in the read-only snapshot volume according to the number of data objects in the second state, and determine the number of objects in the read-only snapshot volume according to the number of data objects in the second state. Calculate the occupied capacity of the read-only snapshot by the number of objects and object size of the read snapshot volume;

respectively determining the number of data objects in the first state and the second state in the object state table, and determining the explicit read-only snapshot volume according to the number of the first state and the number of the second state and the number of objects in the hidden clone snapshot volume, and the capacity occupied by the writable snapshot is calculated according to the number and size of objects in the explicit read-only snapshot volume and the hidden clone snapshot volume.

Optionally, after performing a write operation on the target data object according to the overwrite instruction to obtain a new logical volume, the method further includes:

When a snapshot rollback instruction is received, a snapshot rollback operation is performed on the new logical volume according to the target data object in the read-only snapshot volume.

The present application also provides a system for determining the occupied capacity of a snapshot, and the system for determining includes:

a clone module, configured to determine a target data object corresponding to the overwrite instruction in the original logical volume when an overwrite instruction is received, and create a clone object in the read-only snapshot volume that is consistent with the content of the target data object;

an overwrite module, configured to perform a write operation on the target data object according to the overwrite instruction to obtain a new logical volume;

A readable data writing module, configured to write the logical volume mirror data corresponding to the new logical volume in the explicit read-only snapshot volume, and update the hidden clone snapshot volume according to the content in the target data object after the write operation;

A capacity calculation module, configured to determine the snapshot occupied capacity according to the number of objects in the read-only snapshot volume, the explicit read-only snapshot volume and the hidden clone snapshot volume.

Optionally, when the snapshot occupied capacity includes the read-only snapshot occupied capacity and the writable snapshot occupied capacity, the capacity calculation module includes:

a read-only capacity calculation unit, configured to calculate the read-only snapshot occupied capacity according to the number of objects and the object size of the read-only snapshot volume;

A writable capacity calculation unit, configured to calculate the occupied capacity of the writable snapshot according to the number and size of objects in the explicit read-only snapshot volume and the hidden clone snapshot volume.

The present application also provides a computer-readable storage medium on which a computer program is stored, and when the computer program is executed, the steps performed by the above-mentioned method for determining the occupied capacity of a snapshot are implemented.

The present application also provides an electronic device, including a memory and a processor, where a computer program is stored in the memory, and when the processor invokes the computer program in the memory, the above-mentioned method for determining the occupied capacity of a snapshot executes the steps.

The present application provides a method for determining the occupied capacity of a snapshot, which includes, when an overwrite instruction is received, determining a target data object corresponding to the overwrite instruction in the original logical volume, and creating a read-only snapshot volume with the target data object corresponding to the overwrite instruction. A clone object with the same content of the target data object; perform a write operation on the target data object according to the overwrite instruction to obtain a new logical volume; write the logical volume mirror data corresponding to the new logical volume in the explicit read-only snapshot volume , and update the hidden clone snapshot volume according to the content in the target data object after the write operation; determine the snapshot occupation according to the number of objects in the read-only snapshot volume, the explicit read-only snapshot volume and the hidden clone snapshot volume capacity.

In the present application, a clone object corresponding to the content to be written is created before the overwrite operation of the original logical volume is performed. After the overwrite operation, not only the mirror data of the logical volume corresponding to the new logical volume is generated, but also the hidden clone snapshot volume is updated according to the content to be written before. Used to record new business data. Compared with the prior art, the snapshot does not change with the reading and writing of the original logical volume after it is created. Therefore, it is not accurate to calculate the occupied capacity only by relying on the snapshot obtained at the time of creation of the original logical volume. This application calculates the snapshot occupied capacity according to the number of objects in the read-only snapshot volume, the explicit read-only snapshot volume and the hidden clone snapshot volume after the overwrite operation is performed, which can accurately describe the occupied capacity of snapshot data and improve distributed block storage. Business storage performance. The present application also provides a system for determining the occupied capacity of a snapshot, a computer-readable storage medium, and an electronic device, which have the above beneficial effects, and are not repeated here.

Description of drawings

In order to describe the embodiments of the present application more clearly, the following will briefly introduce the drawings that are used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application, which are not relevant to ordinary skills in the art. As far as personnel are concerned, other drawings can also be obtained from these drawings on the premise of no creative work.

1 is a flowchart of a method for determining a snapshot occupied capacity provided by an embodiment of the present application;

2 is a flowchart of another method for determining the occupied capacity of a snapshot provided by an embodiment of the present application;

FIG. 3 is a schematic structural diagram of a system for determining a snapshot occupied capacity according to an embodiment of the present application.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments It is a part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

Please refer to FIG. 1 below. FIG. 1 is a flowchart of a method for determining a snapshot occupied capacity provided by an embodiment of the present application.

Specific steps can include:

S101: when an overwrite instruction is received, determine a target data object corresponding to the overwrite instruction in the original logical volume, and create a clone object consistent with the content of the target data object in the read-only snapshot volume;

Among them, there may be an operation of receiving an overwrite instruction before this step. When COW (copy on write) needs to be performed in the original logical volume, an overwrite instruction will be automatically generated, and the new business data needs to be overwritten to the target data object. middle. When the original logical volume is created, the storage system does not create a volume object. When data is written to the original logical volume, a volume object creation operation is triggered and data writing is completed. Therefore, multiple data objects can exist in the original logical volume. That is to say, in this step, the target data object is determined according to the overwriting instruction, that is, it can be indicated that data has been written in the target data object.

Before overwriting the new business data to the target data object, in this step, the target data object of the original logical volume is copied to obtain a clone object that is completely consistent with the data content of the target data object, so that when the snapshot rollback is performed, the cloned object corresponds to the target data object. The snapshot data can be overwritten back to the target data object.

It should be noted that the snapshot volume corresponding to the logical volume in this embodiment has three layers, namely: a read-only snapshot volume, an explicit read-only snapshot volume, and a hidden clone snapshot volume. The clone object obtained by copying is a read-only snapshot. objects in the volume.

S102: Perform a write operation on the target data object according to the overwrite instruction to obtain a new logical volume;

Wherein, on the premise that the target data object has been copied to obtain the cloned object, this step performs a write operation on the target data object according to the overwrite instruction received in S101, and the specific write operation in this step is to overwrite the target data object. For the operation of new business data, after the writing operation is completed, a new logical volume can be obtained, that is, a new logical volume whose target data object has changed relative to the original logical volume.

To illustrate the operation process of this embodiment, for example, the original logical volume includes data objects object1 and object2, and after receiving the overwrite instruction, it is determined that the target data object corresponding to the overwrite instruction in the original logical volume is object1. Create a clone object object1-snap1 for object1 in the read-only snapshot volume. The clone object object1-snap1 has the same data as the data object object1. After the clone object object1-snap1 is created, the overwrite operation is performed on the object1 of the original logical volume, the data in the object1 changes, and the object1 is marked as object1'.

S103: Write the logical volume mirror data corresponding to the new logical volume in the explicit read-only snapshot volume, and update the hidden clone snapshot volume according to the content in the target data object after performing the write operation;

Wherein, after the overwrite operation is performed on the original logical volume, this step generates the logical volume mirror data of the new logical volume and writes the logical volume mirror data to the explicit read-only snapshot volume. In this step, the content in the target data object after the write operation is also updated to the hidden clone snapshot volume, that is, the new business data written in S102 is written into the hidden clone snapshot volume.

S104: Determine the snapshot occupied capacity according to the number of objects in the read-only snapshot volume, the explicit read-only snapshot volume, and the hidden clone snapshot volume.

Wherein, once the snapshot of the original logical volume is created in the prior art, the snapshot does not change with the read and write operations of the original logical volume. Therefore, in the prior art, if the copy-on-write operation of the original logical volume is performed, the previous snapshot is still stored. The capacity is used as the current used capacity of the logical volume, so there is a problem that the description is wrong. In this embodiment, after the copy-on-write operation is performed on the original logical volume, the three-tier snapshot of the logical volume is updated, and the objects in the read-only snapshot volume, the explicit read-only snapshot volume and the hidden clone snapshot volume can be updated according to the The number determines the capacity occupied by the snapshot. The space occupied by each object in the snapshot volume is fixed, so the snapshot occupied capacity can be determined according to the number of objects in the read-only snapshot volume, the explicit read-only snapshot volume and the hidden clone snapshot volume. It should be noted that, by determining the occupied capacity of the snapshot in this step, the capacity occupancy status of the new logical volume can be known.

As a preferred implementation manner, the following operations may also exist after S104:

When a snapshot rollback instruction is received, a snapshot rollback operation is performed on the new logical volume according to the target data object in the read-only snapshot volume.

In this embodiment, a clone object corresponding to the content to be written is created before the overwrite operation of the original logical volume is performed. After the overwrite operation, not only the mirror data of the logical volume corresponding to the new logical volume is generated, but also the hidden clone snapshot is updated according to the content to be written before. Volumes are used to record new business data. Compared with the prior art, the snapshot does not change with the reading and writing of the original logical volume after it is created. Therefore, it is not accurate to calculate the occupied capacity only by relying on the snapshot obtained at the time of creation of the original logical volume. This embodiment calculates the snapshot occupied capacity according to the number of objects in the read-only snapshot volume, the explicit read-only snapshot volume, and the hidden clone snapshot volume after the overwrite operation is performed, which can accurately describe the occupied capacity of the snapshot data and improve the distributed block size. Storage performance of storage services.

Further, the snapshot occupied capacity described in the embodiment corresponding to FIG. 1 may include the read-only snapshot occupied capacity and the writable snapshot occupied capacity;

The capacity occupied by the read-only snapshot is the capacity occupied by the data in the read-only snapshot volume, and the read-only snapshot data in the read-only snapshot volume is the mirror data of the original volume (that is, the data in the clone object) generated by COW. The capacity occupied by the writable snapshot is the capacity occupied by the data in the explicit read-only snapshot volume and the hidden clone snapshot volume. The writable snapshot data can include the mirror data of the new logical volume and the newly written business data.

Both read-only snapshot data and writable snapshot data are stored in the object, and the size of the object is fixed, generally 4M. Therefore, the data of the two snapshots will occupy storage space, so this embodiment proposes the concept of occupied capacity for the capacity of the snapshot data: the size of the storage space that the snapshot actually occupies in the distributed storage system. The minimum occupied capacity of read-only snapshot data is 0 (when the snapshot is just created), and the maximum is the size of the original logical volume (completely overwrites the original volume); the minimum occupied capacity of writable snapshot data is 0, and the maximum is the size of the original logical volume. 2x (completely overwrites the original volume and writes to the writable snapshot at the same time).

Correspondingly, in the embodiment corresponding to FIG. 1, determining the snapshot occupied capacity according to the number of objects in the read-only snapshot volume, the explicit read-only snapshot volume and the hidden clone snapshot volume mentioned in S104 may include the following steps:

Step 1: Calculate the occupied capacity of the read-only snapshot according to the number of objects and the object size of the read-only snapshot volume;

Step 2: Calculate the occupied capacity of the writable snapshot according to the number and size of objects in the explicit read-only snapshot volume and the hidden clone snapshot volume.

Please refer to FIG. 2 below. FIG. 2 is a flowchart of another method for determining the occupied capacity of a snapshot provided by an embodiment of the present application. The specific steps may include:

S201: When it is detected that a new data object is created in the logical volume, set a state corresponding to the new data object in the object state table to a first state.

S202: when an overwrite instruction is received, determine a target data object corresponding to the overwrite instruction in the original logical volume, and create a clone object in the read-only snapshot volume that is consistent with the content of the target data object;

S203: Perform a write operation on the target data object according to the overwrite write instruction to obtain a new logical volume, and set the state corresponding to the target data object in the object state table as a second state.

S204: Write the logical volume mirror data corresponding to the new logical volume in the explicit read-only snapshot volume, and update the hidden clone snapshot volume according to the content in the target data object after the write operation;

S205: Determine the number of data objects whose state is the second state in the object state table, determine the number of objects of the read-only snapshot volume according to the number of data objects whose state is the second state, and determine the number of objects of the read-only snapshot volume according to the number of data objects whose state is the second state. Calculate the occupied capacity of the read-only snapshot by calculating the number of objects and the object size of the read-only snapshot volume;

S206: Determine the number of data objects whose states are the first state and the second state in the object state table respectively, and determine the explicit read-only according to the number of the first state and the number of the second state The number of objects in the snapshot volume and the hidden clone snapshot volume, and the occupied capacity of the writable snapshot is calculated according to the number and size of objects in the explicit read-only snapshot volume and the hidden clone snapshot volume.

It should be noted that, in this embodiment, before the target data object is created in S201 by default, the state corresponding to the target data object in the object state table may be the third state. Each snapshot volume may have a corresponding object state sub-table, and in this embodiment, the set of all object state sub-tables is called an object state table. The object status table may include the status of all objects in the read-only snapshot volume, the explicit read-only snapshot volume and the hidden clone snapshot volume. The above-mentioned first state may be "absence", and the second state may be: "existence".

For example, to illustrate the above process, when the object state table is created, the state of all objects is set to "absent", and the state of the corresponding snapshot object is modified to "exist" in the COW process. The capacity occupied by snapshots is calculated in two cases: read-only snapshots and writable snapshots: the capacity calculation of read-only snapshots counts the number of objects whose status is "existing" in the object status table, and multiplies the number of objects by the size of the objects to obtain the occupied capacity of snapshots; writable snapshots It consists of two parts: explicit read-only snapshots and hidden clone volumes. The explicit read-only snapshots contain the mirror data of new logical volumes, and the hidden clone volumes store new business data. Therefore, the capacity occupied by writable snapshots needs to be counted separately to display read-only snapshots and hidden clone volumes. Objects whose volume status is "exist".

The processes described in the above embodiments are described below through embodiments in practical applications.

Step 1. When creating a snapshot for a logical volume, create a snapshot objectmap with the same size as the volume objectmap for the read-only snapshot, and the state of the objects is initially "absent". For the writable snapshot, use the existing process to participate in addition to the objectmap. Hide the objectmap of the cloned volume.

Step 2. When overwriting the original volume, find the snapshot with the latest creation time of the volume, that is, the latest snapshot.

Step 3. When overwriting the original volume object, check whether the snapshot object corresponding to the object in the latest snapshot is in the "existing" state.

Step 4. If the status in Step 3 is "Exist", directly overwrite the original volume object. If the status in step 3 is "absent", first set the status of the snapshot object to "exist", and then overwrite the original object.

Step 5. When writing data to the writable snapshot, the objectmap update rule of the hidden clone volume is consistent with the current distributed block storage logic.

Step 6. For the read-only snapshot, count the number of objects in the snapshot objectmap whose status is "existing", and multiply it by the object size to obtain the snapshot occupied capacity.

Step 7. For writable snapshots, count the number of objects in the "existing" status in the snapshot objectmap and the hidden clone volume objectmap respectively, and multiply the number by the object size to obtain the actual occupied capacity of the writable snapshot.

This embodiment redefines the concept of snapshot occupied capacity for the current distributed block storage, and improves the user experience of related distributed block services; computing snapshot occupied capacity based on objectmap shortens the computing time and improves the storage performance of distributed block services .

Please refer to FIG. 3, which is a schematic structural diagram of a system for determining the occupied capacity of a snapshot according to an embodiment of the present application;

The system can include:

The cloning module 100 is configured to, when an overwrite instruction is received, determine a target data object corresponding to the overwrite instruction in the original logical volume, and create a clone object in the read-only snapshot volume that is consistent with the content of the target data object ;

an overwriting module 200, configured to perform a write operation on the target data object according to the overwriting instruction to obtain a new logical volume;

The readable data writing module 300 is configured to write the logical volume mirror data corresponding to the new logical volume in the explicit read-only snapshot volume, and update the hidden clone snapshot volume according to the content in the target data object after the write operation is performed ;

The capacity calculation module 400 is configured to determine the occupied capacity of a snapshot according to the number of objects in the read-only snapshot volume, the explicit read-only snapshot volume and the hidden clone snapshot volume.

In this embodiment, a clone object corresponding to the content to be written is created before the overwrite operation of the original logical volume is performed. After the overwrite operation, not only the mirror data of the logical volume corresponding to the new logical volume is generated, but also the hidden clone snapshot is updated according to the content to be written before. Volumes are used to record new business data. Compared with the prior art, the snapshot does not change with the reading and writing of the original logical volume after it is created. Therefore, it is not accurate to calculate the occupied capacity only by relying on the snapshot obtained at the time of creation of the original logical volume. This embodiment calculates the snapshot occupied capacity according to the number of objects in the read-only snapshot volume, the explicit read-only snapshot volume, and the hidden clone snapshot volume after the overwrite operation is performed, which can accurately describe the occupied capacity of the snapshot data and improve the distributed block size. Storage performance of storage services.

Further, when the snapshot occupied capacity includes the read-only snapshot occupied capacity and the writable snapshot occupied capacity, the capacity calculation module 400 includes:

a read-only capacity calculation unit, configured to calculate the read-only snapshot occupied capacity according to the number of objects and the object size of the read-only snapshot volume;

A writable capacity calculation unit, configured to calculate the occupied capacity of the writable snapshot according to the number and size of objects in the explicit read-only snapshot volume and the hidden clone snapshot volume.

Further, the system also includes:

The first state setting module is configured to set the state corresponding to the new data object in the object state table to the first state when it is detected that a new data object is created in the logical volume.

Further, the system also includes:

The second state setting module is configured to set the state corresponding to the target data object in the object state table as the second state.

Further, when the snapshot occupied capacity includes the read-only snapshot occupied capacity and the writable snapshot occupied capacity, the capacity calculation module 400 includes:

A first computing unit, configured to determine the number of data objects whose state is the second state in the object state table, and determine the read-only snapshot volume according to the number of data objects whose state is the second state; The number of objects, the capacity occupied by the read-only snapshot is calculated according to the number of objects and the object size of the read-only snapshot volume;

The second calculation unit is configured to respectively determine the number of data objects whose states are the first state and the second state in the object state table, and determine the number of data objects according to the number of the first state and the number of the second state. The number of objects in the explicit read-only snapshot volume and the hidden clone snapshot volume, and the capacity occupied by the writable snapshot is calculated according to the number and size of objects in the explicit read-only snapshot volume and the hidden clone snapshot volume .

Further, the system also includes:

A rollback module, configured to perform a snapshot rollback operation on the new logical volume according to the target data object in the read-only snapshot volume when a snapshot rollback instruction is received.

Since the embodiments of the system part correspond to the embodiments of the method part, for the embodiments of the system part, please refer to the description of the embodiments of the method part, which will not be repeated here.

The present application also provides a computer-readable storage medium on which a computer program is stored, and when the computer program is executed, the steps provided by the above embodiments can be implemented. The storage medium may include: U disk, removable hard disk, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), magnetic disk or optical disk and other media that can store program codes.

The present application also provides an electronic device, which may include a memory and a processor, where a computer program is stored in the memory, and when the processor invokes the computer program in the memory, the steps provided in the above embodiments can be implemented. Of course, the electronic device may also include various network interfaces, power supplies and other components.

The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the various embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant part can be referred to the description of the method. It should be pointed out that for those of ordinary skill in the art, without departing from the principles of the present application, several improvements and modifications can also be made to the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

It should also be noted that, in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply these entities or operations. There is no such actual relationship or sequence between operations. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device that includes a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, article or apparatus. Without further limitation, an element qualified by the phrase "comprising a..." does not preclude the presence of additional identical elements in a process, method, article, or device that includes the element.

Claims (10)

1. a kind of snapshot, which occupies, holds method for determination of amount characterized by comprising

When receiving covering write command, target data objects corresponding with the covering write command in original logical volume are determined, and Creation and the consistent cloned object of target data objects content in read-only materialized view volume；

Write operation is executed to the target data objects according to the covering write command and obtains new logical volumes；

Be written the corresponding logical volume mirror image data of the new logical volumes in explicit read-only materialized view volume, and according to execute write operation it The content update in target data objects afterwards hides clone's snapped volume；

It is determined according to the number of objects in read-only materialized view volume, the explicit read-only materialized view volume and hiding clone's snapped volume fast According to occupancy capacity.

2. determining method according to claim 1, which is characterized in that when snapshot occupancy capacity includes that read-only materialized view occupies When capacity and writeable snapshot occupy capacity, according to read-only materialized view volume, the explicit read-only materialized view volume and the hiding clone Number of objects in snapped volume determines that snapshot occupies capacity and includes:

The read-only materialized view, which is calculated, according to the number of objects of read-only materialized view volume and object size occupies capacity；

It can according to the number of objects and object size calculating in the explicit read-only materialized view volume and hiding clone's snapped volume It writes snapshot and occupies capacity.

3. determining method according to claim 1, which is characterized in that before receiving the covering write command, further includes:

It, will be corresponding with the new data-objects in Obj State table when detecting creation new data-objects in the logical volume State is set as first state.

4. determining method according to claim 3, which is characterized in that covered in the target data objects execution to the logical volume After overwrite operation, further includes:

The second state is set by state corresponding with the target data objects in the Obj State table.

5. determining method according to claim 4, which is characterized in that when snapshot occupancy capacity includes that read-only materialized view occupies When capacity and writeable snapshot occupy capacity, according to read-only materialized view volume, the explicit read-only materialized view volume and the hiding clone Number of objects in snapped volume determines that snapshot occupies capacity and includes:

It determines that state is the quantity of the data object of second state in the Obj State table, is described according to the state The quantity of the data object of second state determines the number of objects of the read-only materialized view volume, the number of objects rolled up according to the read-only materialized view The read-only materialized view, which is calculated, with object size occupies capacity；

Determine that state in the Obj State table is the quantity of the data object of the first state and second state respectively, Determine that the explicit read-only materialized view volume and the hiding clone are fast according to the quantity of the quantity of the first state and the second state According to the number of objects in volume, according to the number of objects and object size in the explicit read-only materialized view volume and hiding clone's snapped volume It calculates the writeable snapshot and occupies capacity.

6. according to claim 1 to any one of 5 determining methods, which is characterized in that according to the covering write command to institute Target data objects are stated to execute after write operation obtains new logical volumes, further includes:

When receiving snapshot rollback instruction, the new logical volumes are held according to the target data objects in read-only materialized view volume Row snapshot rolling back action.

7. the determination system that a kind of snapshot occupies capacity characterized by comprising

Cloning module, for determining mesh corresponding with the covering write command in original logical volume when receiving covering write command Mark data object, and creation and the consistent cloned object of target data objects content in read-only materialized view volume；

Writing module is covered, obtains new logic for executing write operation to the target data objects according to the covering write command Volume；

Readable data writing module, for the corresponding logical volume mirror image number of the new logical volumes to be written in explicit read-only materialized view volume According to, and clone's snapped volume is hidden according to the content update in the target data objects after execution write operation；

Capacity calculation module, for according to read-only materialized view volume, the explicit read-only materialized view volume and hiding clone's snapshot Number of objects in volume determines that snapshot occupies capacity.

8. determining system according to claim 7, which is characterized in that when snapshot occupancy capacity includes that read-only materialized view occupies When capacity and writeable snapshot occupy capacity, the capacity calculation module includes:

Read-only capacity calculating unit, number of objects and object size for being rolled up according to the read-only materialized view calculate the read-only materialized view Occupy capacity；

Writeable capacity calculating unit, for according to the number of objects in the explicit read-only materialized view volume and hiding clone's snapped volume The writeable snapshot, which is calculated, with object size occupies capacity.

9. a kind of electronic equipment characterized by comprising

Memory, for storing computer program；

Processor, realizing that snapshot occupies capacity as described in any one of claim 1 to 6 when for executing the computer program The step of determining method.

10. a kind of computer readable storage medium, which is characterized in that be stored with computer on the computer readable storage medium Program realizes that snapshot occupies capacity really as described in any one of claim 1 to 6 when the computer program is executed by processor The step of determining method.