Proxmox ZFS tuning

zfstune.sh

#!/bin/bash
# ZFS Performance Tuning - Non-persistent (apply after each reboot)
# Auto-detects pools, datasets, and disks

set -e

echo "=== ZFS Performance Tuning ==="

# --- ARC: set to ~200GB (adjust if your servers have less RAM) ---
ARC_MAX=214748364800
echo "Setting ARC max to $(( ARC_MAX / 1073741824 ))GB..."
echo $ARC_MAX | tee /sys/module/zfs/parameters/zfs_arc_max

# --- IO queue depths for SSDs ---
echo "Setting IO queue depths..."
echo 64 | tee /sys/module/zfs/parameters/zfs_vdev_sync_read_max_active
sleep 1
echo 64 | tee /sys/module/zfs/parameters/zfs_vdev_sync_write_max_active
sleep 1
echo 64 | tee /sys/module/zfs/parameters/zfs_vdev_async_read_max_active
sleep 1
echo 64 | tee /sys/module/zfs/parameters/zfs_vdev_async_write_max_active
#sleep 1
#echo 64 | tee /sys/module/zfs/parameters/zfs_vdev_async_max_active

# --- txg timeout ---
echo "Setting txg timeout to 10s..."
echo 10 | tee /sys/module/zfs/parameters/zfs_txg_timeout

# --- Set scheduler to none for all disks in ZFS pools ---
echo "Setting IO scheduler to none for ZFS disks..."
for POOL in $(zpool list -H -o name); do
    for DISK in $(zpool status "$POOL" | grep -E '^\s+(sd|nvme|vd)' | awk '{print $1}' | sed 's/[0-9]*$//'); do
        BLOCKDEV=$(echo "$DISK" | sed 's/p$//')
        if [ -f "/sys/block/$BLOCKDEV/queue/scheduler" ]; then
            echo "  $BLOCKDEV -> none"
            echo none | tee /sys/block/$BLOCKDEV/queue/scheduler > /dev/null
        fi
    done
done

# --- atime=off on all ZFS filesystem datasets ---
echo "Disabling atime on filesystem datasets..."
for DS in $(zfs list -H -o name,type | awk '$2 == "filesystem" {print $1}'); do
    echo "  atime=off on $DS"
    zfs set atime=off "$DS"
done

# --- sync=disabled on all pools ---
echo "Disabling sync on all pools..."
for POOL in $(zpool list -H -o name); do
    echo "  sync=disabled on $POOL"
    zfs set sync=disabled "$POOL"
done

echo ""
echo "=== Done. Current ARC size: ==="
grep "^size" /proc/spl/kstat/zfs/arcstats
echo ""
echo "=== Pool overview: ==="
zpool list