From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 306A5C43334 for ; Wed, 15 Jun 2022 13:00:01 +0000 (UTC) Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-207-GsbfNJt9M1KDCt4LjEFnVA-1; Wed, 15 Jun 2022 08:59:58 -0400 X-MC-Unique: GsbfNJt9M1KDCt4LjEFnVA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 2331B800971; Wed, 15 Jun 2022 12:59:56 +0000 (UTC) Received: from mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (unknown [10.30.29.100]) by smtp.corp.redhat.com (Postfix) with ESMTP id A7C802166B26; Wed, 15 Jun 2022 12:59:49 +0000 (UTC) Received: from mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (localhost [IPv6:::1]) by mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (Postfix) with ESMTP id 1335D1947041; Wed, 15 Jun 2022 12:59:49 +0000 (UTC) Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) by mm-prod-listman-01.mail-001.prod.us-east-1.aws.redhat.com (Postfix) with ESMTP id 8BF2019466DF for ; Wed, 15 Jun 2022 12:40:49 +0000 (UTC) Received: by smtp.corp.redhat.com (Postfix) id 6AFC22026D64; Wed, 15 Jun 2022 12:40:49 +0000 (UTC) Received: from mimecast-mx02.redhat.com (mimecast10.extmail.prod.ext.rdu2.redhat.com [10.11.55.26]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 670F42026D07 for ; Wed, 15 Jun 2022 12:40:49 +0000 (UTC) Received: from us-smtp-1.mimecast.com (us-smtp-delivery-1.mimecast.com [205.139.110.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 2DCEA1C06EC7 for ; Wed, 15 Jun 2022 12:40:49 +0000 (UTC) Received: from plutone.assyoma.it (host195-56-237-212.serverdedicati.aruba.it [212.237.56.195]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-574-kFyjHmswPMaVeoQZjqICSA-1; Wed, 15 Jun 2022 08:40:44 -0400 X-MC-Unique: kFyjHmswPMaVeoQZjqICSA-1 Received: from webmail.assyoma.it (localhost [IPv6:::1]) by plutone.assyoma.it (Postfix) with ESMTPA id EBB381DDAED2; Wed, 15 Jun 2022 14:40:29 +0200 (CEST) MIME-Version: 1.0 Date: Wed, 15 Jun 2022 14:40:29 +0200 From: Gionatan Danti To: Zhiyong Ye In-Reply-To: References: <9c22b11a-b539-1974-7994-6835eea82bfd@bytedance.com> <8baee796-9bfb-47a8-1661-7e94437826c9@bytedance.com> <5970db8d-462f-0e35-741c-fa0fdc188fa2@bytedance.com> <31a7b7e9ea9e60fe42d93f6f113fcaf0@assyoma.it> User-Agent: Roundcube Webmail/1.4.13 Message-ID: X-Sender: g.danti@assyoma.it X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 Subject: Re: [linux-lvm] Why is the performance of my lvmthin snapshot so poor X-BeenThere: linux-lvm@redhat.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: LVM general discussion and development Cc: LVM general discussion and development Errors-To: linux-lvm-bounces@redhat.com Sender: "linux-lvm" X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=linux-lvm-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Il 2022-06-15 11:46 Zhiyong Ye ha scritto: > I also think it meets expectations. But is there any other way to > optimize snapshot performance at the code level? Does it help to > reduce the chunksize size in the code, I see in the help documentation > that the chunksize can only be 64k minimum. I don't think forcing the code to use smaller recordsize is a good idea. Considering the hard limit on metadata size (16 GB max), 64K chunks are good for ~16 TB thin pool - already relatively small. A, say, 16K recordsize would be good for a 4 TB pool only, an so on. Moreover, sequential performance will significantly suffer. I think you have to accept the performance hit on first chunck allocation & rewrite. Regards. -- Danti Gionatan Supporto Tecnico Assyoma S.r.l. - www.assyoma.it email: g.danti@assyoma.it - info@assyoma.it GPG public key ID: FF5F32A8 _______________________________________________ linux-lvm mailing list linux-lvm@redhat.com https://listman.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/