From: Daniel Berteaud <daniel@firewall-services.com>
To: Proxmox VE user list <pve-user@lists.proxmox.com>
Subject: Re: [PVE-User] PBS : is dirty-bitmap really accurate ?
Date: Thu, 23 Jul 2020 08:53:01 +0200 (CEST) [thread overview]
Message-ID: <141180690.77175.1595487181182.JavaMail.zimbra@fws.fr> (raw)
In-Reply-To: <1595486387.pi9zv7y79a.astroid@nora.none>
----- Le 23 Juil 20, à 8:43, Fabian Grünbichler f.gruenbichler@proxmox.com a écrit :
> 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
I'm running pve-qemu-kvm 5.0.0-11, and all the implied VM have been either (cold) rebooted, or migrated.
>
> 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.
>
Yes, I'd expect some amplification, but not that much. For my Zabbix server, it's nearly canceling all the benefit of using a dirty bitmap.
One thing I've noted, is that I get expected values at least for one guest, running PfSense (where I get ~150MB of dirty blocks each days). Most of my other VM are Linux, I'll check if it could be related to the atime update or something
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:[~2020-07-23 6:59 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 [this message]
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
2020-07-24 7:54 ` Ronny Aasen
2020-07-26 9:24 ` Mark Schouten
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