From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [IPv6:2a01:7e0:0:424::9]) by lore.proxmox.com (Postfix) with ESMTPS id 981851FF14C for ; Fri, 26 Jun 2026 09:51:45 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id B14669201; Fri, 26 Jun 2026 09:51:43 +0200 (CEST) From: Maximiliano Sandoval To: pve-devel@lists.proxmox.com Subject: [PATCH docs] qm: reflect changes in the freeze apis Date: Fri, 26 Jun 2026 09:51:28 +0200 Message-ID: <20260626075138.138302-1-m.sandoval@proxmox.com> X-Mailer: git-send-email 2.47.3 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Bm-Milter-Handled: 55990f41-d878-4baa-be0a-ee34c49e34d2 X-Bm-Transport-Timestamp: 1782460293056 X-SPAM-LEVEL: Spam detection results: 0 AWL 0.124 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 URIBL_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to URIBL was blocked. See http://wiki.apache.org/spamassassin/DnsBlocklists#dnsbl-block for more information. [proxmox.com,qemu.org] Message-ID-Hash: Y5WID6RK6ZYFSKPLXZ7QXFTWCFUJ4KLR X-Message-ID-Hash: Y5WID6RK6ZYFSKPLXZ7QXFTWCFUJ4KLR X-MailFrom: m.sandoval@proxmox.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; loop; banned-address; emergency; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.10 Precedence: list List-Id: Proxmox VE development discussion List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: The current docs reference 'fs-freeze' commands, but there are no such qga commands. We either refer to the commands by their complete name or informally as "freeze" and "thaw". A link to the guest agent reference is added, since it contains interesting information, e.g. that on Windows a thaw is issued automatically 10s. The docs for the UI's side are updated to reflect the changes on the labels and explain where this option is located. Signed-off-by: Maximiliano Sandoval --- qm.adoc | 28 +++++++++++++++++----------- 1 file changed, 17 insertions(+), 11 deletions(-) diff --git a/qm.adoc b/qm.adoc index 96ba68b..b9a3529 100644 --- a/qm.adoc +++ b/qm.adoc @@ -1553,7 +1553,8 @@ For example, the IP addresses in the VM summary panel are fetched via the guest agent. Or when starting a backup, the guest is told via the guest agent to sync -outstanding writes via the 'fs-freeze' and 'fs-thaw' commands. +outstanding writes via the `guest-fsfreeze-freeze` and `guest-fsfreeze-thaw` +commands. For the guest agent to work properly the following steps must be taken: @@ -1603,10 +1604,14 @@ Filesystem Freeze & Thaw By default, if the QEMU Guest Agent is enabled in the guest's config and if the agent is available inside of the guest, then the virtual machine's filesystems -are synced via the 'fs-freeze' QEMU Guest Agent command when certain operations -are performed. This is done to provide data consistency. +are synced via the `guest-fsfreeze-freeze` QEMU Guest Agent command when certain +operations are performed. This is done to provide data consistency. -An 'fs-freeze' will be issued for any of the following operations on a VM: +See the +https://www.qemu.org/docs/master/interop/qemu-ga-ref.html[QEMU Guest Agent Protocol Reference] +for more details. + +An freeze will be issued for any of the following operations on a VM: * Performing a backup in snapshot mode * Creating a clone of a VM while it is running @@ -1616,9 +1621,9 @@ An 'fs-freeze' will be issued for any of the following operations on a VM: running guest On Windows guests, some applications might handle consistent backups themselves -by hooking into the Windows VSS (Volume Shadow Copy Service) layer, a -'fs-freeze' then might interfere with that. For example, it has been observed -that calling 'fs-freeze' with some SQL Servers triggers VSS to call the SQL +by hooking into the Windows VSS (Volume Shadow Copy Service) layer, a freeze +then might interfere with that. For example, it has been observed that calling +`guest-fsfreeze-freeze` with some SQL Servers triggers VSS to call the SQL Writer VSS module in a mode that breaks the SQL Server backup chain for differential backups. @@ -1627,10 +1632,11 @@ There are two options on how to handle such a situation. 1. Configure the QEMU Guest Agent to use a different VSS variant that does not interfere with other VSS users. The https://pve.proxmox.com/wiki/VM_Backup_Consistency[{pve} wiki] has more details. -2. Alternatively, you can configure {pve} to not issue a freeze-and-thaw cycle on -backup by setting the `freeze-fs-on-backup` QGA option to `0`. This can also be -done via the GUI with the 'Freeze/thaw guest filesystems on backup for -consistency' option. +2. Alternatively, you can configure {pve} to not issue a freeze-and-thaw cycles +by disabling the `freeze-fs` guest agent option. This can also be done via the +GUI at the options panel of the virtual machine, then on the 'Freeze/thaw guest +filesystems during certain operations for consistency' option inside the 'QEMU +Guest Agent' dialog. + IMPORTANT: Disabling this option can potentially lead to backups with inconsistent filesystems. Therefore, adapting the QEMU Guest Agent -- 2.47.3