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datto / dattobd

kernel module for taking block-level snapshots and incremental backups of Linux block devices
GNU General Public License v2.0
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Very Slow to take snapshot #373

Closed yito24 closed 1 month ago

yito24 commented 1 month ago

It is slow to take snapshots of 0.11.7. For 0.11.6, it takes about 0.342 seconds to snapshot 4 volumes. For 0.11.7, it takes about 27 seconds to snapshot 4 volumes.

Why does it take so long?

0.11.6.txt 0.11.7.txt lsblk.txt

Swistusmen commented 1 month ago

Hi, thank you for noticing that, we will make investigations about this topic in the future, but for now, it seems to be good enough. Slow down is caused by switching block-layer API in kernel 5.9

yito24 commented 1 month ago

Thanks for your reply.

I tried it on CentOS7.9, but it takes about 27 seconds. If the timing of snapshots of each volume is shifted, there is a concern that it will affect Oracle etc.

backup_20240517102348.txt

Swistusmen commented 1 month ago

We are trying to firstly satisfy our primary limited distributions which are listed here: https://continuity.datto.com/help/Content/kb/siris-alto-nas/360040893811.html for now we have other concerns to focus on. If the speed will become a real obstacle for us, we will focus on that much more