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 C77051FF15C for ; Fri, 28 Nov 2025 16:56:47 +0100 (CET) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id AD5FF1EA01; Fri, 28 Nov 2025 16:57:06 +0100 (CET) From: Fiona Ebner To: pve-devel@lists.proxmox.com Date: Fri, 28 Nov 2025 16:56:09 +0100 Message-ID: <20251128155628.223336-1-f.ebner@proxmox.com> X-Mailer: git-send-email 2.47.3 MIME-Version: 1.0 X-Bm-Milter-Handled: 55990f41-d878-4baa-be0a-ee34c49e34d2 X-Bm-Transport-Timestamp: 1764345353804 X-SPAM-LEVEL: Spam detection results: 0 AWL -0.017 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 RCVD_IN_VALIDITY_CERTIFIED_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to Validity was blocked. See https://knowledge.validity.com/hc/en-us/articles/20961730681243 for more information. RCVD_IN_VALIDITY_RPBL_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to Validity was blocked. See https://knowledge.validity.com/hc/en-us/articles/20961730681243 for more information. RCVD_IN_VALIDITY_SAFE_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to Validity was blocked. See https://knowledge.validity.com/hc/en-us/articles/20961730681243 for more information. SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record Subject: [pve-devel] [PATCH docs] storage: note that qcow2 internal snapshots are inefficient X-BeenThere: pve-devel@lists.proxmox.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Proxmox VE development discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Proxmox VE development discussion Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: pve-devel-bounces@lists.proxmox.com Sender: "pve-devel" It's a commonly reported issue, most recently again in the enterprise support, that taking or removing snapshots of large qcow2 files on file-based network storages can take a very long time. Add a note about this limitation. Signed-off-by: Fiona Ebner --- pvesm.adoc | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/pvesm.adoc b/pvesm.adoc index d36baf8..165b446 100644 --- a/pvesm.adoc +++ b/pvesm.adoc @@ -88,6 +88,11 @@ block device functionality. ^2^: On file based storages, snapshots are possible with the 'qcow2' format, either using the internal snapshot function, or snapshots as volume chains^4^. +Creating and deleting internal 'qcow2' snapshots will block a running VM and +is not an efficient operation. The performance is particularly bad with network +storages like NFS. On some setups and for large disks (multiple hundred GiB or +TiB sized), these operations may take several minutes, or in extreme cases, even +hours. ^3^: It is possible to use LVM on top of an iSCSI or FC-based storage. That way you get a `shared` LVM storage -- 2.47.3 _______________________________________________ pve-devel mailing list pve-devel@lists.proxmox.com https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel