CN106294026A - Mapping table restoration methods after a kind of solid-state disk powered-off fault and system thereof - Google Patents

Abstract

The invention discloses a method and system for restoring a mapping table after abnormal power failure of a solid-state disk. Snapshot fragment pages are divided into odd-numbered snapshot fragment pages and even-numbered snapshot fragment pages according to the page number parity of stored logical pages and modified data, and are stored separately. In the odd channel and the even channel in the flash memory; when the solid state disk recovers from power failure, read the mapping information stored in the abnormal power failure and the mapping table last stored in the flash memory before the abnormal power failure; the mapping information includes The location information of the last stored mapping table and the start and end addresses of the snapshot segment pages stored in the flash memory after the last stored mapping table starts to be written to the flash memory; Pages and even-numbered snapshot fragment pages update the last stored mapping table, and N is an even number. The invention can enhance the degree of parallel processing during power-off recovery, thereby shortening the power-off recovery time.

Description

Method and system for restoring mapping table after abnormal power failure of solid state disk

technical field

The invention relates to the technical field of snapshots, in particular to a method and system for restoring a mapping table after a solid state disk is powered off abnormally.

Background technique

With the advancement of NAND flash memory technology, the capacity of solid-state disks (including multiple flash memory chips in solid-state disks) is getting larger and larger, and the metadata of solid-state disks, especially the mapping table, is also getting larger and larger. As a result, the mapping table loses a lot of important data. At present, it is generally used to increase the capacitor to prolong the power-down time, and at the same time use the snapshot technology to save the snapshot segment with the changed mapping information to the flash memory.

Wherein, the snapshot technology refers to taking a snapshot of information in a mapping table from a logical page to a physical page. The normal working process of the solid-state disk is: when the memory receives the updated mapping information, generate a snapshot segment based on the mapping information and store it in the snapshot segment page (physical page), and update the mapping table content in the memory; when the snapshot segment page capacity When it is full, the snapshot segment page is flushed into the flash memory, and when the number of snapshot segment pages flushed into the flash memory reaches a preset threshold, the mapping table in the memory is flushed into the flash memory.

However, at present, when the power-off recovery is performed on the mapping table, the problem of long recovery time often occurs due to the large amount of data to be recovered, and the reliability is low.

Therefore, how to provide a method and system for restoring a mapping table after an abnormal power failure of a solid state disk with a short power failure recovery time is a problem to be solved by those skilled in the art at present.

Contents of the invention

The object of the present invention is to provide a method and system for restoring a mapping table after an abnormal power failure of a solid state disk, which can enhance the degree of parallel processing during power failure recovery, shorten the power failure recovery time, and improve the reliability of the solid state disk.

In order to solve the above-mentioned technical problems, the present invention provides a method for restoring a mapping table after an abnormal power failure of a solid-state disk. The flash memory of the solid-state disk includes odd-numbered channels for storing odd-numbered snapshot fragment pages and for storing The even-numbered channels, the odd-numbered snapshot fragment pages have odd-numbered logical page modification data in memory, and the even-numbered snapshot fragment pages have even-numbered logical page modification data in memory; the method includes:

When the solid state disk recovers from power failure, read the mapping information stored during abnormal power failure and the mapping table last stored in the flash memory before abnormal power failure from the flash memory; wherein, the mapping information includes the The location information of the last stored mapping table and the start and end addresses of the snapshot segment pages stored in the flash memory after the moment when the last stored mapping table starts to be written to the flash memory;

N CPUs respectively read odd-numbered snapshot fragment pages and even-numbered snapshot fragment pages according to the start and end addresses; and update the last stored mapping table according to the read odd-numbered snapshot fragment pages and even-numbered snapshot fragment pages, N is an even number.

Preferably, the process of updating the last stored mapping table according to the odd-numbered snapshot fragment pages and the even-numbered snapshot fragment pages obtained by reading is specifically:

Read the snapshot fragment pages in the corresponding channel in the order of the time stored in the flash memory from late to early;

Determine whether the corresponding logical page data in the currently read snapshot fragment page has been modified during this update process, if so, ignore the modification of the logical page data this time, if not, follow the currently read The snapshot segment page modifies the logical page data.

Preferably, the process of storing the odd-numbered snapshot fragment page into the odd-numbered channel and the even-numbered snapshot fragment page into the even-numbered channel is specifically:

After receiving the logical page modification data, if the page number of the logical page modification data is an odd number, use the logical page modification data as the odd logical page modification data, and generate a corresponding odd snapshot segment; if the logical page modification data The page number is an even number, using the logical page modification data as the even logical page modification data, and generating corresponding even snapshot fragments;

storing the generated odd-numbered snapshot fragments or the even-numbered snapshot fragments in corresponding physical pages;

When the physical page storing the odd-numbered snapshot fragments is full, write the physical page as an odd-numbered snapshot fragment page into an odd-numbered channel in the flash memory;

When the physical page storing the even-numbered snapshot fragments is full, write the physical page as an even-numbered snapshot fragment page into an even-numbered channel in the flash memory;

When the solid-state disk is abnormally powered off, the odd-numbered snapshot segment pages and the even-numbered snapshot segment pages that have not yet been written to the flash memory are written into corresponding odd-numbered channels and even-numbered channels respectively.

Preferably, the process of reading the mapping information stored during abnormal power failure from the flash memory is specifically:

read metadata information from the flash memory;

Acquiring the mapping information recorded in the metadata information during abnormal power failure.

Preferably, there are two odd-numbered channels and two even-numbered channels.

Preferably, N is 2, and one of the CPUs reads odd-numbered snapshot fragment pages according to the start and end addresses, and performs an update operation on the last stored mapping table according to the read odd-numbered snapshot fragment pages; The CPU reads even-numbered snapshot fragment pages according to the start and end addresses, and performs an update operation on the last stored mapping table according to the read even-numbered snapshot fragment pages.

In order to solve the above-mentioned technical problems, the present invention also provides a system for recovering the mapping table after abnormal power failure of the solid-state disk. For the even channel of the page, the odd logical page modification data is stored in the odd snapshot segment page, and the even logical page modification data is stored in the even snapshot segment page; the system includes:

The reading module is used to read the mapping information stored during abnormal power failure and the mapping table last stored by the flash memory before the abnormal power failure from the flash memory when the solid state disk is recovering from power failure; wherein, The mapping information includes the location information of the last stored mapping table and the start and end addresses of the snapshot segment pages stored in the flash memory after the moment when the last stored mapping table starts to be written to the flash memory;

N CPUs are used to respectively read the odd-numbered snapshot fragment pages and the even-numbered snapshot fragment pages according to the start and end addresses; and update the last stored mapping table according to the read odd-numbered snapshot fragment pages and even-numbered snapshot fragment pages operation, N is an even number.

The invention provides a method and system for restoring a mapping table after an abnormal power failure of a solid-state disk. The snapshot segment pages are divided into odd-numbered snapshot segment pages and even-numbered snapshot segment pages, and respectively store odd-numbered logical page modification data and even-numbered logical page modification data. ; and the odd-numbered snapshot segment pages and the even-numbered snapshot segment pages are stored in the odd-numbered channels and the even-numbered channels of the flash memory respectively; when the solid state disk recovers from power failure, multiple CPUs can be used to read the odd-numbered snapshot segment pages and the even-numbered snapshot segments respectively page and update the mapping table. It can be seen that the present invention enhances the degree of parallel processing during power-off recovery by means of parity separation, thereby shortening the power-off recovery time and improving the reliability of the solid-state disk.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the prior art and the accompanying drawings that need to be used in the embodiments. Obviously, the accompanying drawings in the following description are only some of the present invention. Embodiments, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort.

Fig. 1 is the flow chart of the process of the mapping table recovery method after a kind of solid-state disk abnormal power failure provided by the present invention;

FIG. 2 is a schematic structural diagram of a system for restoring a mapping table after an abnormal power failure of a solid state disk provided by the present invention.

detailed description

The core of the present invention is to provide a method and system for restoring a mapping table after an abnormal power failure of a solid-state disk, which can enhance the degree of parallel processing during power-failure recovery, further shorten the time for power-failure recovery, and improve the reliability of the solid-state disk.

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

The invention provides a method for restoring a mapping table after an abnormal power failure of a solid-state disk. The flash memory of the solid-state disk includes odd-numbered channels for storing odd-numbered snapshot fragment pages and even-numbered channels for storing even-numbered snapshot fragment pages, and odd-numbered snapshot fragment pages. There are odd logical page modification data in the internal memory, and even logical page modification data in the even snapshot fragment page memory; see Figure 1, which is a flow chart of the process of a method for restoring the mapping table after an abnormal power failure of a solid state disk provided by the present invention Figure; the method includes:

Step s101: When the solid state disk is recovering from power failure, read the mapping information stored during abnormal power failure and the last stored mapping table before the abnormal power failure from the flash memory; wherein, the mapping information includes the last stored mapping table location information and the start and end addresses of the snapshot segment pages stored in the flash memory after the last time the stored mapping table starts to be written to the flash memory;

Step s102: N CPUs respectively read odd-numbered snapshot fragment pages and even-numbered snapshot fragment pages according to the start and end addresses; and update the last stored mapping table according to the read odd-numbered snapshot fragment pages and even-numbered snapshot fragment pages, where N is even.

It should be noted that even CPUs read snapshot fragment pages in odd channels and even channels respectively.

It is understandable that in the snapshot technology, when the number of snapshot fragment pages flushed into the flash memory reaches the preset threshold, the mapping table in the memory will be flushed into the flash memory, and if an abnormal power failure occurs at this time , it is very likely that the number of snapshot fragment pages flashed into the flash memory at this time does not reach the preset threshold (for example, the mapping table is saved every 20 pages are flushed, but only 10 snapshot fragment pages may be stored when the power is abnormally cut off), which means In this case, the last mapping table is stored in the flash memory, and the mapping table corresponding to the information in the 10 pages of snapshot fragments has not been stored in the flash memory but is still in the memory, and will be lost after power-off. Afterwards, the mapping table is updated according to the 10 snapshot fragment pages. Therefore, in order to avoid useless operations, it is necessary to record the start and end addresses of the snapshot segment pages whose number does not reach the preset threshold during abnormal power failure, so as to find these snapshot segment pages according to the start and end addresses during recovery.

Preferably, the process of updating the last stored mapping table according to the read odd-numbered snapshot fragment pages and even-numbered snapshot fragment pages is specifically as follows:

Read the snapshot fragment pages in the corresponding channel in the order of the time stored in the flash memory from the latest to the earliest;

Determine whether the corresponding logical page data in the currently read snapshot fragment page has been modified during this update process, if so, ignore the modification of the logical page data this time, if not, follow the currently read snapshot fragment page to Logical page data is modified.

It can be understood that, by adopting the above operations, unnecessary modification and writing operations can be reduced as much as possible, the recovery time of the mapping table after power-on can be shortened, and the reliability of the solid-state disk can be improved.

Specifically, the process of storing odd-numbered snapshot fragment pages into odd-numbered channels and even-numbered snapshot fragment pages into even-numbered channels is as follows:

After receiving the logical page modification data, if the page number of the logical page modification data is odd, treat the logical page modification data as odd logical page modification data, and generate corresponding odd snapshot fragments; if the page number of the logical page modification data is even, convert the logical page modification data to Page modification data is used as even logical page modification data, and corresponding even snapshot fragments are generated;

Store the generated odd-numbered snapshot fragments or even-numbered snapshot fragments in corresponding physical pages respectively;

When the physical page storing the odd-numbered snapshot fragments is full, the physical page is written to an odd-numbered channel in the flash memory as an odd-numbered snapshot fragment page;

When the physical page storing even-numbered snapshot fragments is full, write the physical page as an even-numbered snapshot fragment page to an even channel in the flash memory;

When the solid-state disk is abnormally powered off, the odd-numbered snapshot segment pages and the even-numbered snapshot segment pages that have not yet been written to the flash memory are written to the corresponding odd-numbered channels and even-numbered channels respectively.

As preferably, the process of reading the mapping information stored during abnormal power failure from the flash memory is specifically:

Read metadata information from flash memory;

Obtain the mapping information recorded in the metadata information during abnormal power failure.

Preferably, there are two odd-numbered channels and two even-numbered channels.

Preferably, N is 2, one CPU reads the odd-numbered snapshot fragment pages according to the start and end addresses, and updates the last stored mapping table according to the read odd-numbered snapshot fragment pages; the other CPU reads the even-numbered snapshot fragment pages according to the start and end addresses Snapshot fragment pages, and update the last stored mapping table according to the read even-numbered snapshot fragment pages.

It is understandable that when there is no distinction between parity and parity, the number of snapshot fragment pages in the memory is at least two. When a snapshot fragment page is full and written to flash memory, it will take a certain amount of time. A new snapshot segment is generated, so another snapshot segment page is required as a replacement. Therefore, when dividing parity, at least 4 snapshot fragment pages must be set in the memory, two as odd snapshot fragment pages, and two as even snapshot fragment pages. Correspondingly, there are at least one odd-numbered channel and even-numbered channel respectively. Correspondingly, there are at least two CPUs, which process the snapshot fragment pages in the odd-numbered channel and the even-numbered channel respectively, so as to improve the parallel processing capability and reduce the recovery time after abnormal power failure.

Further, when there are multiple odd-numbered channels and even-numbered channels, more than two CPUs can be set correspondingly, further reducing recovery time. Of course, the set number of CPUs is determined according to the number of channels and actual conditions, which is not limited in the present invention.

The invention provides a method for restoring a mapping table after an abnormal power failure of a solid-state disk. The snapshot segment pages are divided into odd-numbered snapshot segment pages and even-numbered snapshot segment pages, and respectively store odd-numbered logical page modification data and even-numbered logical page modification data; and odd-numbered Snapshot fragment pages and even-numbered snapshot fragment pages are stored in the odd-numbered and even-numbered channels of the flash memory respectively; when the SSD recovers from power failure, multiple CPUs can be used to read the odd-numbered snapshot fragment pages and the even-numbered snapshot fragment pages respectively and The mapping table is updated. It can be seen that the present invention enhances the degree of parallel processing during power-off recovery by means of parity separation, thereby shortening the power-off recovery time and improving the reliability of the solid-state disk.

The present invention also provides a system for restoring the mapping table after abnormal power failure of the solid-state disk. The flash memory of the solid-state disk includes odd-numbered channels for storing odd-numbered snapshot fragment pages and even-numbered channels for storing even-numbered snapshot fragment pages. There are odd logical page modification data in the page memory, and even logical page modification data in the even snapshot fragment page memory; see Fig. 2, Fig. 2 is a schematic structural diagram of a mapping table recovery system after an abnormal power failure of a solid-state disk provided by the present invention . The system includes:

The reading module 11 is used to read the mapping information stored during abnormal power failure and the mapping table stored in the flash memory for the last time before abnormal power failure from the flash memory when the solid state disk is restored from power failure; wherein, the mapping information includes the last The location information of the stored mapping table and the start and end addresses of the snapshot segment pages stored in the flash memory after the last time the stored mapping table starts to be written to the flash memory;

N CPUs 12 are used to read odd snapshot fragment pages and even snapshot fragment pages respectively according to the start and end addresses; and update the last stored mapping table according to the read odd snapshot fragment pages and even snapshot fragment pages, where N is even.

It should be noted that the even number of CPUs 12 respectively read the snapshot segment pages in the odd numbered channel and the even numbered channel.

The invention provides a mapping table recovery system after abnormal power failure of a solid state disk, which divides snapshot fragment pages into odd snapshot fragment pages and even snapshot fragment pages, and stores odd logical page modification data and even logical page modification data respectively; Snapshot fragment pages and even-numbered snapshot fragment pages are stored in the odd-numbered and even-numbered channels of the flash memory respectively; when the SSD recovers from power failure, multiple CPUs can be used to read the odd-numbered snapshot fragment pages and the even-numbered snapshot fragment pages respectively and The mapping table is updated. It can be seen that the present invention enhances the degree of parallel processing during power-off recovery by means of parity separation, thereby shortening the power-off recovery time and improving the reliability of the solid-state disk.

It should be noted that in this specification, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article or device comprising a set of elements includes not only those elements , but also includes other elements not expressly listed, or also includes elements inherent in such process, method, article or equipment. Without further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article or apparatus comprising said element.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (7)

1. the mapping table restoration methods after a solid-state disk powered-off fault, it is characterised in that include in the flash memory of described solid-state disk For storing the odd chanel of odd number snapshot fragment page and for storing the even-numbered channels of even number snapshot fragment page, described odd number Snapshot fragment page internal memory has odd to revise data, has even pages amendment number in described even number snapshot fragment page According to；Described method includes:

When described solid-state disk carries out power loss recovery, the map information stored when reading powered-off fault in described flash memory and institute State flash memory mapping table of last storage before powered-off fault；Wherein, described map information includes described depositing for the last time The positional information of the mapping table of storage and the mapping table of described last storage start to write with a brush dipped in Chinese ink to described flash memory moment it After be stored in the start-stop address of snapshot fragment page of described flash memory；

N number of CPU reads odd number snapshot fragment page and even number snapshot fragment page respectively according to described start-stop address；And according to reading The odd number snapshot fragment page obtained and even number snapshot fragment page are updated operation to the mapping table of described last storage, N is even number.

Method the most according to claim 1, it is characterised in that the described described odd number snapshot fragment page obtained according to reading And described even number snapshot fragment page the mapping table of described last storage is updated operation process particularly as follows:

The snapshot fragment page in respective channel is read by evening to order early according to the time being stored in described flash memory；

Judge that in the current snapshot fragment page read, corresponding logical page data was repaiied in this renewal process the most Change, if so, ignore the amendment this time to described logical page data, if it is not, according to the snapshot fragment page of described current reading to institute State logical page data to modify.

Method the most according to claim 1, it is characterised in that described odd number snapshot fragment page be stored in described odd chanel with And described even number snapshot fragment page be stored in described even-numbered channels process particularly as follows:

After receiving logical page (LPAGE) amendment data, if the page number of described logical page (LPAGE) amendment data is odd number, described logical page (LPAGE) is revised Data revise data as odd, and generate corresponding odd number snapshot fragment；If the page of described logical page (LPAGE) amendment data Code is even number, as even pages, described logical page (LPAGE) amendment data is revised data, and generates corresponding even number snapshot fragment；

The described odd number snapshot fragment generated or described even number snapshot fragment are stored respectively to corresponding Physical Page；

After the Physical Page storing described odd number snapshot fragment is filled with, using described Physical Page as odd number snapshot fragment page brush In the odd chanel being written in described flash memory；

After the Physical Page storing described even number snapshot fragment is filled with, using described Physical Page as even number snapshot fragment page brush In the even-numbered channels being written in described flash memory；

When powered-off fault occurs in described solid-state disk, currently will not yet write with a brush dipped in Chinese ink the odd number snapshot fragment page to described flash memory and idol Number snapshot fragment page is write with a brush dipped in Chinese ink respectively to corresponding odd chanel and even-numbered channels.

Method the most according to claim 1, it is characterised in that described storage during reading powered-off fault in described flash memory The process of map information particularly as follows:

Metadata information is read in described flash memory；

Described map information during the powered-off fault recorded in obtaining described metadata information.

Method the most according to claim 1, it is characterised in that described odd chanel and described even-numbered channels are 2.

Method the most according to claim 1, it is characterised in that N is 2, a described CPU reads according to described start-stop address Odd number snapshot fragment page, and according to reading the odd number snapshot fragment page obtained, the mapping table of described last storage is carried out more New operation；Another described CPU reads even number snapshot fragment page according to described start-stop address, and fast according to reading the even number obtained Photo section page is updated operation to the mapping table of described last storage.

7. the mapping table recovery system after a solid-state disk powered-off fault, it is characterised in that include in the flash memory of described solid-state disk For storing the odd chanel of odd number snapshot fragment page and for storing the even-numbered channels of even number snapshot fragment page, described odd number Snapshot fragment page internal memory has odd to revise data, has even pages amendment number in described even number snapshot fragment page According to；Described system includes:

Read module, for when described solid-state disk carries out power loss recovery, stores when reading powered-off fault in described flash memory Map information and described flash memory be the mapping table of last storage before powered-off fault；Wherein, described map information includes The positional information of the mapping table of described last storage and start to write with a brush dipped in Chinese ink to institute at the mapping table of described last storage The start-stop address of the snapshot fragment page of described flash memory it is stored in after the moment stating flash memory；

N number of CPU, for reading odd number snapshot fragment page and even number snapshot fragment page respectively according to described start-stop address；And root The mapping table of described last storage is carried out more by the odd number snapshot fragment page and the even number snapshot fragment page that obtain according to reading New operation, N is even number.