From: Daniel Berteaud <daniel@firewall-services.com>
To: Roland <devzero@web.de>
Cc: Proxmox VE user list <pve-user@lists.proxmox.com>
Subject: Re: [PVE-User] PBS : is dirty-bitmap really accurate ?
Date: Fri, 24 Jul 2020 09:02:30 +0200 (CEST) [thread overview]
Message-ID: <945247964.82475.1595574150577.JavaMail.zimbra@fws.fr> (raw)
In-Reply-To: <d9f00e30-0369-6936-bdb1-2a8bf1955c8b@web.de>
----- Le 23 Juil 20, à 23:59, Roland devzero@web.de a écrit :
> i just had a look on that, too - i was backing up a VM i backed up this
> afternoon,
>
> and for my curiosity 1GB out of 15GB was marked dirty.
>
> that looks a quite much for me for a mostly idle system, because there
> was definitely only a little bit of change on the system within logfiles
> in /var/log
>
> so i wonder what marked all that blocks dirty....
>
> i'm also suspecting atime changes...will keep an eye on that....
It was my daily fstrim in my case. Each time you trim, it'll dirty all the blocks corresponding to unused space.
I've switched this to a weekly job so bacups can run most of the time efficiently. Since then, dirty blocks went from ~15GB per VM on average to something betwwen 800MB and 4GB, which is much closer to what I expect, considering the 4MB granularity of the bitmap.
I'll check on my biggest VM (Zabbix server) but I expect similar results
Thanks Fabian and Jorge for pointing this out
Cheers
Daniel
--
[ https://www.firewall-services.com/ ]
Daniel Berteaud
FIREWALL-SERVICES SAS, La sécurité des réseaux
Société de Services en Logiciels Libres
Tél : +33.5 56 64 15 32
Matrix: @dani:fws.fr
[ https://www.firewall-services.com/ | https://www.firewall-services.com ]
next prev parent reply other threads:[~2020-07-24 7:03 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-22 16:40 Daniel Berteaud
2020-07-23 6:43 ` Fabian Grünbichler
2020-07-23 6:53 ` Daniel Berteaud
2020-07-23 9:00 ` Jorge Boncompte
2020-07-23 9:34 ` Fabian Grünbichler
2020-07-23 9:40 ` Daniel Berteaud
2020-07-23 21:59 ` Roland
2020-07-24 7:02 ` Daniel Berteaud [this message]
2020-07-24 7:54 ` Ronny Aasen
2020-07-26 9:24 ` Mark Schouten
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