From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68]) by lore.proxmox.com (Postfix) with ESMTPS id 349FE1FF15F for ; Mon, 18 Nov 2024 10:25:15 +0100 (CET) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id D843FB403; Mon, 18 Nov 2024 10:25:20 +0100 (CET) From: Christian Ebner To: pbs-devel@lists.proxmox.com Date: Mon, 18 Nov 2024 10:24:34 +0100 Message-Id: <20241118092435.81880-3-c.ebner@proxmox.com> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20241118092435.81880-1-c.ebner@proxmox.com> References: <20241118092435.81880-1-c.ebner@proxmox.com> MIME-Version: 1.0 X-SPAM-LEVEL: Spam detection results: 0 AWL 0.031 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: [pbs-devel] [PATCH docs 2/3] docs: reference technical change detection mode section for client 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: , Reply-To: Proxmox Backup Server development discussion Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: pbs-devel-bounces@lists.proxmox.com Sender: "pbs-devel" Currently, the change detection modes are described in the client usage section, not intended for in-depth explanation on how these client option works, but rather with focus on how to use them. Therefore, add a reference to the more detailed technical section regarding the change detection modes and reduce duplicate explanations. Signed-off-by: Christian Ebner --- docs/backup-client.rst | 21 ++++++--------------- 1 file changed, 6 insertions(+), 15 deletions(-) diff --git a/docs/backup-client.rst b/docs/backup-client.rst index e56e0625b..78e856979 100644 --- a/docs/backup-client.rst +++ b/docs/backup-client.rst @@ -301,24 +301,15 @@ the client to avoid re-reading files with unchanged metadata whenever possible. When using this mode, instead of the regular pxar archive, the backup snapshot is stored into two separate files: the `mpxar` containing the archive's metadata and the `ppxar` containing a concatenation of the file contents. This splitting -allows for efficient metadata lookups. +allows for efficient metadata lookups. When creating the backup archives, the +current file metadata is compared to the one looked up in the previous `mpxar` +archive. The operational details are explained more in depth in the +:ref:`technical documentation `. Using the `change-detection-mode` set to `data` allows to create the same split archive as when using the `metadata` mode, but without using a previous -reference and therefore reencoding all file payloads. -When creating the backup archives, the current file metadata is compared to the -one looked up in the previous `mpxar` archive. -The metadata comparison includes file size, file type, ownership and permission -information, as well as acls and attributes and most importantly the file's -mtime, for details see the -:ref:`pxar metadata archive format `. - -If unchanged, the entry is cached for possible re-use of content chunks without -re-reading, by indexing the already present chunks containing the contents from -the previous backup snapshot. Since the file might only partially re-use chunks -(thereby introducing wasted space in the form of padding), the decision whether -to re-use or re-encode the currently cached entries is postponed to when enough -information is available, comparing the possible padding to a threshold value. +reference and therefore reencoding all file payloads. For details of this mode +please see the :ref:`technical documentation `. .. _client_change_detection_mode_table: -- 2.39.5 _______________________________________________ pbs-devel mailing list pbs-devel@lists.proxmox.com https://lists.proxmox.com/cgi-bin/mailman/listinfo/pbs-devel