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 E24A492382 for ; Fri, 5 Apr 2024 13:40:25 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id BF68C128C1 for ; Fri, 5 Apr 2024 13:39:55 +0200 (CEST) Received: from proxmox-new.maurer-it.com (proxmox-new.maurer-it.com [94.136.29.106]) (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 for ; Fri, 5 Apr 2024 13:39:54 +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 7D38D46458 for ; Fri, 5 Apr 2024 13:39:54 +0200 (CEST) Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable In-Reply-To: <20240328123707.336951-1-c.ebner@proxmox.com> References: <20240328123707.336951-1-c.ebner@proxmox.com> From: Fabian =?utf-8?q?Gr=C3=BCnbichler?= To: Christian Ebner , pbs-devel@lists.proxmox.com Date: Fri, 05 Apr 2024 13:39:47 +0200 Message-ID: <171231718790.2418221.3224184974223438557@yuna.proxmox.com> User-Agent: alot/0.10 X-SPAM-LEVEL: Spam detection results: 0 AWL 0.058 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% DMARC_MISSING 0.1 Missing DMARC policy KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment 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 v3 pxar proxmox-backup 00/58] fix #3174: improve file-level backup 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: Fri, 05 Apr 2024 11:40:25 -0000 Quoting Christian Ebner (2024-03-28 13:36:09) > A big thank you to Dietmar and Fabian for the review of the previous > version and Fabian for extensive testing and help during debugging. >=20 > This series of patches implements an metadata based file change > detection mechanism for improved pxar file level backup creation speed > for unchanged files. >=20 > The chosen approach is to split pxar archives on creation via the > proxmox-backup-client into two separate data and upload streams, > one exclusive for regular file payloads, the other one for the rest > of the pxar archive, which is mostly metadata. >=20 > On consecutive runs, the metadata archive of the previous backup run, > which is limited in size and therefore rapidly accessed is used to > lookup and compare the metadata for entries to encode. > This assumes that the connection speed to the Proxmox Backup Server is > sufficiently fast, allowing the download and chaching of the chunks for > that index. >=20 > Changes to regular files are detected by comparing all of the files > metadata object, including mtime, acls, ecc. If no changes are detected, > the previous payload index is used to lookup chunks to possibly re-use > in the payload stream of the new archive. > In order to reduce possible chunk fragmentation, the decision whether to > re-use or re-encode a file payload is deferred until enough information > is gathered by adding entries to a look-ahead cache. If the padding > introduced by reusing chunks falls below a threshold, the entries are > referenced, the chunks are re-used and injected into the pxar payload > upload stream, otherwise they are discated and the files encoded > regularly. There's still some not-too-fundamental refactoring in the feedback this time around, but it's alreayd taking up shape. A few bigger open questions: - maybe do some test runs with different non-sliding-window chunking approa= ches - what to do about the catalog? with the split archives, it would be nice to get rid of the overhead of having two metadata archives.. - CliParams/Prelude: what to use it for, and how (other than the parameters= /CLI excludes) - should we add a mode to force split archive, but no-reuse (for example, allowing to reset padding overhead every X backups) - more testing, also of pathologically constructed input would be great (bo= th for validation, and for performance/reuse regression testing) Also, clippy doesn't like some of the new code, maybe you could take a look= at those as well, it's mostly minor stuff like unnecessary reference taking.. Thanks for all your work on this, I am sure this will be a big step forward= in extending the use cases where PBS makes sense :)