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public:data_integrity_check

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Data Integrity Check

Data backup is essential to business or organization and having a data backup plan is only as good as the integrity of the backup data. To ensure that this objective is met, AhsayCBS backup server and AhsayOBM/AhsayACB client provides an improved Data Integrity Check (DIC) feature where the end user can easily verify the integrity of the data stored on the backup destination(s) (i.e. AhsayCBS, Cloud storage, or Local storage) to ensure that the backup data is recoverable.

In backing up large or even small file(s), data corruption may still occur during a backup job or even in a post-backup job. Some of the possible causes are:

  • Bad program exits (i.e. AhsayCBS/AhsayOBM/AhsayACB application terminated unexpectedly when an active backup job is in progress)
  • Technical problems on the AhsayOBM/AhsayACB client machine (e.g. hardware failure, unexpected reboot, unexpected loss of power)
  • Technical problems on the AhsayCBS backup server (e.g. hardware failure, unexpected reboot, unexpected loss of power, storage issues, human error)
  • Technical problems on the cloud storage service

Since data corruption is always a possibility, the solution is to identify and then remove corrupted files from the backup destination(s). Identifying and removing corrupted files from the backup destination(s) is mission critical as it measures the integrity of the backup data and its restorability.

The primary role of the Data Integrity Check is to identify and remove corrupted files from the backup destination(s). This will allow the next backup job to have an opportunity to back up these files again. However, corrupted files which are located in the retention area will not be backed up as the source file(s) no longer exists.

Key Features

  • Identify and remove the files and/or folders in the backup destination(s) which do not appear in the index
  • Identify and remove the files and/or folders which appear in the index but do not actually exist in the backup destinations (i.e. AhsayCBS, Cloud storage, or Local storage)
  • Identify and remove corrupted files from the backup destination(s) when the Run Cyclic Redundancy Check (CRC) During Data Integrity Check setting is enabled
  • Identify and remove partially uploaded (orphan) files from the backup destination(s) to free up storage space
  • (TEST MODE) confirmation screen (applicable on AhsayOBM/AhsayACB client)
  • Update storage statistics

Data integrity check CANNOT fix or repair files that are already broken.

Initiating Data Integrity Check (DIC)

Data Integrity Check can be started using the following options:

  • AhsayOBM/AhsayACB client GUI
  • AhsayCBS Web Console for Run on Server (Office 365 and Cloud File) Backup
  • RunDataIntegrityCheck.bat batch file (applicable for Windows operating system only)
  • RunDataIntegrityCheck.sh script file (applicable for FreeBSD/Linux (CLI) operating systems only)

Data Integrity Check (DIC) Modes

There are two (2) data integrity check modes:

  • With Run Cyclic Redundancy Check (CRC) disabled (Default mode)
  • With Run Cyclic Redundancy Check (CRC) enabled

With Run Cyclic Redundancy Check (CRC) disabled (Default mode)

This is the default setting of the data integrity check. Running a data integrity check on this mode allows the AhsayOBM/AhsayACB client or AhsayCBS backup server to perform a comparison between the files and/or folders on the backup destination(s) and the list of the files and/or folders recorded in the current index file.

When should I run a Data Integrity Check in default mode?

  • If you encounter index issues on your backup/restore job
  • If you know or suspect the backup set storage statistics are not updated or incorrect and cannot wait for the next weekly Periodic Data Integrity Check (PDIC) job
  • If you need to remove partially uploaded (orphan) files from the backup destination(s) to free up space, as partially uploaded (orphan) files will remain in the backup destination(s) when backup jobs with large files (i.e. database, VMware/Hyper-V, Windows System) backups are terminated unexpectedly or crashes

With Run Cyclic Redundancy Check (CRC) enabled

Running a data integrity check on this mode will perform check on the integrity of the files in the backup destination(s) against the checksum file generated at the time of the backup job.

If there is a discrepancy, this indicates that the file(s) on the backup destination(s) are corrupted. The AhsayOBM/AhsayACB client or AhsayCBS backup server will remove these files from the backup destination(s). If these files still exist on the client machine or backup server on the next backup job, The AhsayOBM/AhsayACB client or AhsayCBS backup server will upload the latest copy.

For large file sizes, a percentage progress will be displayed throughout the data integrity check job when this setting is enabled:

When should I run a Data Integrity Check with Run Cyclic Redundancy Check (CRC) enabled?

With Periodic Data Integrity Check (PDIC) and post-backup validation features on the AhsayOBM/AhsayACB v8.3.2.11 or above, it is not necessary to frequently run a Data Integrity Check with Run Cyclic Redundancy Check (CRC) enabled. Also, this option can take a long time to complete as the AhsayOBM/AhsayACB will need to download all the files and/or folders from the backup destination(s) on the AhsayOBM/AhsayACB client machine in order to perform the actual Cyclic Redundancy Check (CRC).

To reduce the time taken, you should consider selecting only one backup destination at a time if applicable.

It is recommended to use this option:

  • When the AhsayOBM/AhsayACB client machine encounters “corrupted file” errors during a restore job, running a data integrity check with Cyclic Redundancy Check (CRC) enabled may help to identify and clean up the corrupted files and allows the end user to recover any remaining data from the backup set(s).
  • When a backup destination has encountered a hardware failure (e.g. a disk failure on an AhsayCBS user home drive or AhsayOBM/AhsayACB Local destination drive).

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public/data_integrity_check.1587983300.txt.gz · Last modified: 2020/04/27 18:28 by ronnie.chan