* [PATCH docs 0/2] local-zfs: Rephrase ARC limit
@ 2026-02-24 10:54 Maximiliano Sandoval
2026-02-24 10:54 ` [PATCH docs 1/2] " Maximiliano Sandoval
2026-02-24 10:54 ` [PATCH docs 2/2] local-zfs: add reference to the zfs(4) manual Maximiliano Sandoval
0 siblings, 2 replies; 3+ messages in thread
From: Maximiliano Sandoval @ 2026-02-24 10:54 UTC (permalink / raw)
To: pve-devel
See the first commit for more information.
Regarding adding the manual page: It is not very obvious where to find the
documentation for the value (I was personally interested in the units for
zfs_arc_max). Only after a `man -Kw zfs_arc_max` I found zfs(4) (as its sole
output).
Maximiliano Sandoval (2):
local-zfs: Rephrase ARC limit
local-zfs: add reference to the zfs(4) manual
local-zfs.adoc | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
--
2.47.3
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH docs 1/2] local-zfs: Rephrase ARC limit
2026-02-24 10:54 [PATCH docs 0/2] local-zfs: Rephrase ARC limit Maximiliano Sandoval
@ 2026-02-24 10:54 ` Maximiliano Sandoval
2026-02-24 10:54 ` [PATCH docs 2/2] local-zfs: add reference to the zfs(4) manual Maximiliano Sandoval
1 sibling, 0 replies; 3+ messages in thread
From: Maximiliano Sandoval @ 2026-02-24 10:54 UTC (permalink / raw)
To: pve-devel
We rephrase the current section putting more emphasis on the current
state of things given than Proxmox VE 8.1 was released over two years
ago.
This also frames the problem for pre-existing setups in its own
paragraph.
Signed-off-by: Maximiliano Sandoval <m.sandoval@proxmox.com>
---
local-zfs.adoc | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/local-zfs.adoc b/local-zfs.adoc
index 4f20d00..12506d1 100644
--- a/local-zfs.adoc
+++ b/local-zfs.adoc
@@ -586,10 +586,13 @@ configured for the root user.
Limit ZFS Memory Usage
~~~~~~~~~~~~~~~~~~~~~~
-ZFS uses '50 %' of the host memory for the **A**daptive **R**eplacement
-**C**ache (ARC) by default. For new installations starting with {pve} 8.1, the
-ARC usage limit will be set to '10 %' of the installed physical memory, clamped
-to a maximum of +16 GiB+. This value is written to `/etc/modprobe.d/zfs.conf`.
+ZFS uses '10 %' of the host memory, clamped to a maximum of +16 GiB+, for the
+**A**daptive **R**eplacement **C**ache (ARC) by default. This value is written
+to `/etc/modprobe.d/zfs.conf` during installation.
+
+Before {pve} 8.1, the ARC usage limit was set to '50 %' without clamping it to a
+maximum size. For existing installations that predate {pve} 8.1, manual steps
+would have to be performed in order to lower the usage limit as described below.
Allocating enough memory for the ARC is crucial for IO performance, so reduce it
with caution. As a general rule of thumb, allocate at least +2 GiB Base + 1
--
2.47.3
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH docs 2/2] local-zfs: add reference to the zfs(4) manual
2026-02-24 10:54 [PATCH docs 0/2] local-zfs: Rephrase ARC limit Maximiliano Sandoval
2026-02-24 10:54 ` [PATCH docs 1/2] " Maximiliano Sandoval
@ 2026-02-24 10:54 ` Maximiliano Sandoval
1 sibling, 0 replies; 3+ messages in thread
From: Maximiliano Sandoval @ 2026-02-24 10:54 UTC (permalink / raw)
To: pve-devel
Signed-off-by: Maximiliano Sandoval <m.sandoval@proxmox.com>
---
local-zfs.adoc | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/local-zfs.adoc b/local-zfs.adoc
index 12506d1..e03379b 100644
--- a/local-zfs.adoc
+++ b/local-zfs.adoc
@@ -588,7 +588,8 @@ Limit ZFS Memory Usage
ZFS uses '10 %' of the host memory, clamped to a maximum of +16 GiB+, for the
**A**daptive **R**eplacement **C**ache (ARC) by default. This value is written
-to `/etc/modprobe.d/zfs.conf` during installation.
+to `/etc/modprobe.d/zfs.conf` during installation. See the manual `man 4 zfs`
+for more information about ZFS kernel module parameters.
Before {pve} 8.1, the ARC usage limit was set to '50 %' without clamping it to a
maximum size. For existing installations that predate {pve} 8.1, manual steps
--
2.47.3
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2026-02-24 10:54 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2026-02-24 10:54 [PATCH docs 0/2] local-zfs: Rephrase ARC limit Maximiliano Sandoval
2026-02-24 10:54 ` [PATCH docs 1/2] " Maximiliano Sandoval
2026-02-24 10:54 ` [PATCH docs 2/2] local-zfs: add reference to the zfs(4) manual Maximiliano Sandoval
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.