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 247871FF136 for ; Mon, 23 Feb 2026 17:01:01 +0100 (CET) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 24D17130C4; Mon, 23 Feb 2026 17:00:48 +0100 (CET) From: Markus Frank To: pve-devel@lists.proxmox.com Subject: [PATCH docs v2 8/11] virtiofs: add documentation for live migration Date: Mon, 23 Feb 2026 16:40:05 +0100 Message-ID: <20260223155951.468572-9-m.frank@proxmox.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260223155951.468572-1-m.frank@proxmox.com> References: <20260223155951.468572-1-m.frank@proxmox.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Bm-Milter-Handled: 55990f41-d878-4baa-be0a-ee34c49e34d2 X-Bm-Transport-Timestamp: 1771862420155 X-SPAM-LEVEL: Spam detection results: 0 AWL -0.143 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 POISEN_SPAM_PILL 0.1 Meta: its spam POISEN_SPAM_PILL_1 0.1 random spam to be learned in bayes POISEN_SPAM_PILL_3 0.1 random spam to be learned in bayes SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record Message-ID-Hash: 4VYTEYXYLCIPPHNKQVXLFZ2OQEWHMD6D X-Message-ID-Hash: 4VYTEYXYLCIPPHNKQVXLFZ2OQEWHMD6D X-MailFrom: m.frank@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: Also update the virtiofs known limitations. Signed-off-by: Markus Frank --- v2 changes: * added link for further information about virtiofs limitations. qm.adoc | 31 ++++++++++++++++++++++++++++++- 1 file changed, 30 insertions(+), 1 deletion(-) diff --git a/qm.adoc b/qm.adoc index 09fbd20..03224a7 100644 --- a/qm.adoc +++ b/qm.adoc @@ -1297,10 +1297,12 @@ Known Limitations * Memory hotplug does not work in combination with virtiofs (also results in hanging access). * Memory related features such as live migration, snapshots, and hibernate are - not available with virtiofs devices. + not available with virtiofs devices on {pve} 8. * Windows cannot understand ACLs in the context of virtiofs. Therefore, do not expose ACLs for Windows VMs, otherwise the virtiofs device will not be visible within the VM. +* For further limitations, see the + https://gitlab.com/virtio-fs/virtiofsd#limitations[GitLab page of virtiofsd]. Add Mapping for Shared Directories ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -1314,6 +1316,29 @@ pvesh create /cluster/mapping/dir --id dir1 \ --map node=node2,path=/path/to/share2 \ ---- +Live Migration +^^^^^^^^^^^^^^ + +Live migration is possible on {pve} 9 (Debian Trixie) because versions of +Virtiofsd starting with v1.11.0 support live migration. To enable live +migration, select a method using the `live-migration-method` parameter in the +Directory Mapping (xref:resource_mapping[Resource Mapping]). If a live migration +method is selected, virtiofsd will start with the flags to enable live migration +using the chosen method. Ensure you are using the same shared directory on both +hosts before migrating. + +Available migration methods are `file-handles` and `find-path`: + +* In the `find-paths` migration mode, virtiofsd tries to find the path inside of + the shared directory for every filesystem object that must be transferred to + the destination. +* In the `file-handles` migration mode every filesystem object is converted to a + file handle. + +For more information about the live migration methods, see the +https://gitlab.com/virtio-fs/virtiofsd/-/blob/main/doc/migration.md[virtiofsd +migration page on GitLab]. + Add virtiofs to a VM ^^^^^^^^^^^^^^^^^^^^ @@ -2162,6 +2187,10 @@ Currently there are the following options: migrating passed through devices is an experimental feature and may not work or cause issues. +* `live-migration-method` (Directory): This sets the live migration mode for + virtiofs. If a live migration method is selected, virtiofsd will start with + the flags to enable live migration using the chosen method. Available + migration methods are `file-handles` and `find-path`. Managing Virtual Machines with `qm` ------------------------------------ -- 2.47.3