Re: [PATCH v4 11/11] blksnap: Kconfig and Makefile

[Sergei Shtepa]

On 6/13/23 01:43, Randy Dunlap wrote:
>> +config BLKSNAP
>> +	tristate "Block Devices Snapshots Module (blksnap)"
>> +	help
>> +	  Allow to create snapshots and track block changes for block devices.
>> +	  Designed for creating backups for simple block devices. Snapshots are
>> +	  temporary and are released then backup is completed. Change block
> 	                             when backup is completed.
> 
> or is the order of operations as listed: release snapshots and then backup
> can be completed?
> 
>> +	  tracking allows to create incremental or differential backups.

"when backup is completed." - it will be more correct.

Normal backup process:

Take snapshot                                        Release snapshot
    |    Start backup                        Finish backup   |
    |        |  Copy data from snapshot images    |          |
------------------------------------------------------------------------->
                                                                         t

In case of failure, for example, when the snapshot is overflowing:

                                           The snapshot is corrupted
Take snapshot                                   | Release snapshot
    |    Start backup                           |   | Finish failed backup
    |        |  Copy data from snapshot images  |   |    |
------------------------------------------------------------------------->
                                                                         t