[pve-devel] [PATCH proxmox-backup 1/3] file-restore: add zfs. prefix to arc_min/max settings

Stoiko Ivanov s.ivanov at proxmox.com
Thu Jun 15 12:42:55 CEST 2023

Currently the values set for zfs_arc_min and zfs_arc_max are ignored
by the kernel:
Unknown kernel command line parameters... will be passed to user space
module parameters provided on the commandline usually need to be
prefixed with the modulename (e.g. zfs.zfs_arc_min, see [0] for a bit
on related information (the issue itself is not related)).

Paradoxically currently ZFS will print spurious warnings about
settings being ignored when they are actually set - see [1].

Booting the debug image and connecting the shell on the serial console
confirmed that the values did not seem to be set:
`grep '^c_' /proc/spl/kstat/zfs/arcstats` showed half of the memory
for c_max.

[0] https://github.com/openzfs/zfs/issues/698
[1] https://github.com/openzfs/zfs/issues/12504

Signed-off-by: Stoiko Ivanov <s.ivanov at proxmox.com>
 proxmox-file-restore/src/qemu_helper.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/proxmox-file-restore/src/qemu_helper.rs b/proxmox-file-restore/src/qemu_helper.rs
index c49f80d9..12c8cabf 100644
--- a/proxmox-file-restore/src/qemu_helper.rs
+++ b/proxmox-file-restore/src/qemu_helper.rs
@@ -260,7 +260,7 @@ pub async fn start_vm(
         // NOTE: ZFS requires that the ARC can at least grow to the max transaction size of 64MB
         // also: setting any of min/max to zero will rather do the opposite of what one wants here
-            "{} panic=1 zfs_arc_min=16777216 zfs_arc_max=67108864 memhp_default_state=online_kernel",
+            "{} panic=1 zfs.zfs_arc_min=16777216 zfs.zfs_arc_max=67108864 memhp_default_state=online_kernel",
             if debug { "debug" } else { "quiet" }

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