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 9E903732D4 for ; Thu, 15 Apr 2021 09:20:04 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 9369F16288 for ; Thu, 15 Apr 2021 09:20:04 +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)) (No client certificate requested) by firstgate.proxmox.com (Proxmox) with ESMTPS id 95A201627E for ; Thu, 15 Apr 2021 09:20:03 +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 53F9945ABD for ; Thu, 15 Apr 2021 09:20:03 +0200 (CEST) Date: Thu, 15 Apr 2021 09:19:56 +0200 From: Fabian =?iso-8859-1?q?Gr=FCnbichler?= To: Dietmar Maurer , Proxmox Backup Server development discussion References: <1688290929.3134.1618418686372@webmail.proxmox.com> In-Reply-To: <1688290929.3134.1618418686372@webmail.proxmox.com> MIME-Version: 1.0 User-Agent: astroid/0.15.0 (https://github.com/astroidmail/astroid) Message-Id: <1618470962.eg8dxuk2ne.astroid@nora.none> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-SPAM-LEVEL: Spam detection results: 0 AWL 0.026 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: [pbs-devel] [PATCH proxmox-backup] backup/verify: improve speed by sorting chunks by inode X-BeenThere: pbs-devel@lists.proxmox.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Proxmox Backup Server development discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 15 Apr 2021 07:20:04 -0000 On April 14, 2021 6:44 pm, Dietmar Maurer wrote: >> zfs with single spinner + fast special device, with a (not counted ;))=20 >> warmup run and everything fitting into cache: >>=20 >> Benchmark #1: stock >> Time (mean =C2=B1 =CF=83): 21.407 s =C2=B1 0.819 s [User: 20.1= ms, System: 15.2 ms] >> Range (min =E2=80=A6 max): 21.070 s =E2=80=A6 23.078 s 6 runs >>=20 >> Benchmark #2: patched >> Time (mean =C2=B1 =CF=83): 47.119 s =C2=B1 0.018 s [User: 29.5= ms, System: 15.1 ms] >> Range (min =E2=80=A6 max): 47.107 s =E2=80=A6 47.154 s 6 runs >>=20 >> Summary >> 'stock' ran >> 2.20 =C2=B1 0.08 times faster than 'patched' >=20 > I assume you have about 3000 chunks? On XFS, I can do 3000 stat() calls p= er second (after cache cleared). > So why the hell are stat calls that slow on ZFS with special device? Or w= hat causes that delay (stat or sort)? 13432 chunks. the run you quoted is with everything in ARC, so this is=20 not even hitting disk (neither special nor regular vdev). I haven't=20 profiled what exactly is the cause of the slowdown. =