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elastio / elastio-snap

kernel module for taking block-level snapshots and incremental backups of Linux block devices
GNU General Public License v2.0
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Create cow file precisely according to the user setting #253

Closed skypodolsky closed 1 year ago

skypodolsky commented 1 year ago

Now, the size of the COW file is the sum of the header size, mapping section, and the snapshot data itself. This was added in one of the previous tasks and caused some issues with yozhik-tests. This approach implicitly adds some additional size to the fallocate specified by the user. After a short discussion we agreed that for the system administrator, it is more critical to precisely control the used disk space used, so we will bring the initial behavior back. This means, that if the user specifies 10% of the disk for the COW file, this should be the precise size of the COW file and no additional data should be added to it.

e-kov commented 1 year ago

Also this task includes test for the CoW file size and fallocate space size checks.