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 4284665B64 for ; Fri, 24 Jul 2020 09:54:21 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 3921B2F684 for ; Fri, 24 Jul 2020 09:54:21 +0200 (CEST) Received: from smtp.jostedal.no (smtp.jostedal.no [217.17.211.26]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by firstgate.proxmox.com (Proxmox) with ESMTPS id 68F772F67A for ; Fri, 24 Jul 2020 09:54:20 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by smtp.jostedal.no (Postfix) with ESMTP id 12A3B5431B for ; Fri, 24 Jul 2020 09:54:14 +0200 (CEST) Received: from smtp.jostedal.no ([127.0.0.1]) by localhost (dpmx.servers.jostedal.no [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id SHNN7CmAv+Ir for ; Fri, 24 Jul 2020 09:54:13 +0200 (CEST) Received: from [10.234.0.29] (95.62-50-191.enivest.net [62.50.191.95]) (Authenticated sender: ronny@aasen.cx) by smtp.jostedal.no (Postfix) with ESMTPSA id CB92C54309 for ; Fri, 24 Jul 2020 09:54:13 +0200 (CEST) Reply-To: ronny+pve-user@aasen.cx To: pve-user@lists.proxmox.com References: <1110267368.76036.1595436034847.JavaMail.zimbra@fws.fr> <1595486387.pi9zv7y79a.astroid@nora.none> <141180690.77175.1595487181182.JavaMail.zimbra@fws.fr> <945247964.82475.1595574150577.JavaMail.zimbra@fws.fr> From: Ronny Aasen Message-ID: Date: Fri, 24 Jul 2020 09:54:13 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0 MIME-Version: 1.0 In-Reply-To: <945247964.82475.1595574150577.JavaMail.zimbra@fws.fr> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-SPAM-LEVEL: Spam detection results: 0 KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment NICE_REPLY_A -0.344 Looks like a legit reply (A) 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: Fri, 24 Jul 2020 07:54:21 -0000 On 24.07.2020 09:02, Daniel Berteaud wrote: > ----- 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 > would mounting the disk with discard help on this ? where it only trims blocks that are actually discarded ? instead of touching the whole disk with fstrim ? Ronny