From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.proxmox.com (Postfix) with ESMTPS id 0AF576564B for ; Thu, 23 Jul 2020 11:34:54 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id ED1952753D for ; Thu, 23 Jul 2020 11:34:23 +0200 (CEST) Received: from proxmox-new.maurer-it.com (proxmox-new.maurer-it.com [212.186.127.180]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by firstgate.proxmox.com (Proxmox) with ESMTPS id 1A6C027533 for ; Thu, 23 Jul 2020 11:34:23 +0200 (CEST) Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id DBB9143339 for ; Thu, 23 Jul 2020 11:34:22 +0200 (CEST) Date: Thu, 23 Jul 2020 11:34:15 +0200 From: Fabian =?iso-8859-1?q?Gr=FCnbichler?= To: Proxmox VE user list References: <1110267368.76036.1595436034847.JavaMail.zimbra@fws.fr> <1595486387.pi9zv7y79a.astroid@nora.none> <141180690.77175.1595487181182.JavaMail.zimbra@fws.fr> <3ce2e15f-9b92-64ce-af55-a21fa46dc5d6@gmail.com> In-Reply-To: <3ce2e15f-9b92-64ce-af55-a21fa46dc5d6@gmail.com> MIME-Version: 1.0 User-Agent: astroid/0.15.0 (https://github.com/astroidmail/astroid) Message-Id: <1595496811.im826y29fq.astroid@nora.none> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-SPAM-LEVEL: Spam detection results: 0 AWL 0.063 Adjusted score from AWL reputation of From: address KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment RCVD_IN_DNSWL_MED -2.3 Sender listed at https://www.dnswl.org/, medium trust SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record Subject: Re: [PVE-User] PBS : is dirty-bitmap really accurate ? X-BeenThere: pve-user@lists.proxmox.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Proxmox VE user list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 23 Jul 2020 09:34:54 -0000 On July 23, 2020 11:00 am, Jorge Boncompte wrote: > El 23/7/20 a las 8:53, Daniel Berteaud escribi=C3=B3: >> ----- Le 23 Juil 20, =C3=A0 8:43, Fabian Gr=C3=BCnbichler f.gruenbichler= @proxmox.com a =C3=A9crit : >>=20 >>> 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=3Dpve-qemu.git;a=3Dcommit;h=3Df257cc05f4fbf7= 72cad3231021b3ce7587127a1b >>=20 >> I'm running pve-qemu-kvm 5.0.0-11, and all the implied VM have been eith= er (cold) rebooted, or migrated. >>=20 >>> >>> the bitmap has a granularity of 4MB, so depending on the activity insid= e >>> 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. >>> >>=20 >> Yes, I'd expect some amplification, but not that much. For my Zabbix ser= ver, 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 gue= st, 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 upda= te or something >=20 > Hi, does the dirty-bitmap take somehow into account block discarding > and zeroing? Because the other thing I would look for in this case is > for a fstrim firing every day. also a possible candidate. trim/discard of course changes the blocks and=20 thus dirties the bitmap. =