From beed14f830fe977b8e9a0f1300a8c941d56ffbff Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Fabian=20Gr=C3=BCnbichler?= Date: Fri, 23 Apr 2021 13:03:43 +0200 Subject: [PATCH] docs: add zfs_arc_min < zfs_arc_max note MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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