From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.proxmox.com (Postfix) with ESMTPS id F146076771 for ; Fri, 23 Apr 2021 13:04:18 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id D9C60282F2 for ; Fri, 23 Apr 2021 13:03:48 +0200 (CEST) Received: from proxmox-new.maurer-it.com (proxmox-new.maurer-it.com [94.136.29.106]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by firstgate.proxmox.com (Proxmox) with ESMTPS id 6CD1B282E7 for ; Fri, 23 Apr 2021 13:03:48 +0200 (CEST) Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id 3FDAF45960 for ; Fri, 23 Apr 2021 13:03:48 +0200 (CEST) From: =?UTF-8?q?Fabian=20Gr=C3=BCnbichler?= To: pve-devel@lists.proxmox.com Date: Fri, 23 Apr 2021 13:03:43 +0200 Message-Id: <20210423110343.1434569-1-f.gruenbichler@proxmox.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-SPAM-LEVEL: Spam detection results: 0 AWL 0.035 Adjusted score from AWL reputation of From: address 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: [pve-devel] [PATCH docs] docs: add zfs_arc_min < zfs_arc_max note 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: , X-List-Received-Date: Fri, 23 Apr 2021 11:04:19 -0000 Signed-off-by: Fabian Grünbichler --- local-zfs.adoc | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/local-zfs.adoc b/local-zfs.adoc index 423f569..0b1ee37 100644 --- a/local-zfs.adoc +++ b/local-zfs.adoc @@ -473,6 +473,19 @@ options zfs zfs_arc_max=8589934592 This example setting limits the usage to 8 GiB ('8 * 2^30^'). +IMPORTANT: In case your desired +zfs_arc_max+ value is lower than or equal to ++zfs_arc_min+ (which defaults to 1/32 of the system memory), +zfs_arc_max+ will +be ignored unless you also set +zfs_arc_min+ to at most +zfs_arc_max - 1+. + +---- +echo "$[8 * 1024*1024*1024 - 1]" >/sys/module/zfs/parameters/zfs_arc_min +echo "$[8 * 1024*1024*1024]" >/sys/module/zfs/parameters/zfs_arc_max +---- + +This example setting (temporarily) limits the usage to 8 GiB ('8 * 2^30^') on +systems with more than 256 GiB of total memory, where simply setting ++zfs_arc_max+ alone would not work. + [IMPORTANT] ==== If your root file system is ZFS, you must update your initramfs every -- 2.20.1