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 AA6A81FF16E for ; Mon, 3 Feb 2025 13:35:04 +0100 (CET) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 11E8D2F14E; Mon, 3 Feb 2025 13:35:03 +0100 (CET) Mime-Version: 1.0 Date: Mon, 03 Feb 2025 13:34:58 +0100 Message-Id: From: "Alexander Zeidler" To: "Proxmox VE development discussion" References: <20250203111448.80291-1-a.abraham@proxmox.com> <20250203111448.80291-2-a.abraham@proxmox.com> In-Reply-To: <20250203111448.80291-2-a.abraham@proxmox.com> X-SPAM-LEVEL: Spam detection results: 0 AWL -0.366 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_ASCII_DIVIDERS 0.8 Email that uses ascii formatting dividers and possible spam tricks 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 URIBL_SBL_A 0.1 Contains URL's A record listed in the Spamhaus SBL blocklist [185.199.110.153, 185.199.111.153, 185.199.108.153] Subject: Re: [pve-devel] [PATCH pve-docs v2 1/2] Section on ZFS and swap corrected. 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 Cc: Alexander Abraham Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: pve-devel-bounces@lists.proxmox.com Sender: "pve-devel" IIRC, there have been some considerations in the past to move the "SWAP on ZFS" section to the chapter "Host System Administration". If doing so: 1. It could be renamed to "SWAP" and, with the current layout, placed between "Disk Health Monitoring" and "Logical Volume Manager (LVM)"? 2. Update the first paragraph accordingly, so that, for example, it includes your new sentences and maybe starts with something like "If using ZFS, [it is strongly recommended ...]". On Mon Feb 3, 2025 at 12:14 PM CET, Alexander Abraham wrote: > --- > local-zfs.adoc | 36 +----------------------------------- > 1 file changed, 1 insertion(+), 35 deletions(-) > > diff --git a/local-zfs.adoc b/local-zfs.adoc > index c64fb27..bcd02f7 100644 > --- a/local-zfs.adoc > +++ b/local-zfs.adoc > @@ -627,41 +627,7 @@ You *must reboot* to activate these changes. > SWAP on ZFS > ~~~~~~~~~~~ > > -Swap-space created on a zvol may generate some troubles, like blocking the > -server or generating a high IO load, often seen when starting a Backup > -to an external Storage. > - > -We strongly recommend to use enough memory, so that you normally do not > -run into low memory situations. Should you need or want to add swap, it is > -preferred to create a partition on a physical disk and use it as a swap device. > -You can leave some space free for this purpose in the advanced options of the > -installer. Additionally, you can lower the > -``swappiness'' value. A good value for servers is 10: > - > ----- > -# sysctl -w vm.swappiness=10 > ----- > - > -To make the swappiness persistent, open `/etc/sysctl.conf` with > -an editor of your choice and add the following line: > - > --------- > -vm.swappiness = 10 > --------- > - > -.Linux kernel `swappiness` parameter values > -[width="100%",cols=" -|=========================================================== > -| Value | Strategy > -| vm.swappiness = 0 | The kernel will swap only to avoid > -an 'out of memory' condition > -| vm.swappiness = 1 | Minimum amount of swapping without > -disabling it entirely. > -| vm.swappiness = 10 | This value is sometimes recommended to > -improve performance when sufficient memory exists in a system. > -| vm.swappiness = 60 | The default value. > -| vm.swappiness = 100 | The kernel will swap aggressively. > -|=========================================================== > +It is strongly recommended to not use a ZFS volume for a swap partition because this could lead to deadlocks freezing thge affected system and other unpredictable behavior. The OpenZFS documentation, which can be viewed https://openzfs.github.io/openzfs-docs/Project%20and%20Community/FAQ.html#using-a-zvol-for-a-swap-device-on-linux[here], warns against using a ZFS volume for a swap partition. > > [[zfs_encryption]] > Encrypted ZFS Datasets _______________________________________________ pve-devel mailing list pve-devel@lists.proxmox.com https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel