On July 22, 2020 6:40 pm, Daniel Berteaud wrote: > Hi > > I've started playing with PBS on some VM. So far, it's looking really > promizing. > There's one strange thing though : the percent of the dirty data. For > example, I backup one VM every 2 or 3 days. It's a moderately busy server, > mainly serving a MariaDB database (zabbix server + mariadb). On each backup, > I get similar dirty values : > > INFO: using fast incremental mode (dirty-bitmap), 492.7 GiB dirty of 590.0 > GiB total > > While I'm sur not even 10% of this has really been written. > > Get more or less the same problem on other VM. One which I know just sleep > all day (my personnal OnlyOffice document server), and which I backup daily, > and get values like : > > INFO: using fast incremental mode (dirty-bitmap), 5.0 GiB dirty of 10.0 GiB > total > > Or another small one (personnal samba DC controler) : > > INFO: using fast incremental mode (dirty-bitmap), 13.0 GiB dirty of 20.0 GiB > total > > The only write activity for those 2 are just a few KB or maybe MB of log > lines. Respectivly 5 and 13GB of dirty blocks seems unreal. > > Am I the only one seeing this ? Could the dirty-bitmap mark dirty blocks > without write activity somehow ?
possibly you haven't upgraded to pve-qemu-kvm 5.0-11 (or your VM hasn't been restarted yet since the upgrade): https://git.proxmox.com/?p=pve-qemu.git;a=commit;h=f257cc05f4fbf772cad3231021b3ce7587127a1b the bitmap has a granularity of 4MB, so depending on the activity inside you can see quite a bit of amplification. also writing and then zeroing/reverting again to the old content would leave a mark in the bitmap without permanently changing the contents. _______________________________________________ pve-user mailing list [email protected] https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-user
