I’ve started encountering a problem that I should use some assistance troubleshooting. I’ve got a Proxmox system that hosts, primarily, my Opnsense router. I’ve had this specific setup for about a year.

Recently, I’ve been experiencing sluggishness and noticed that the IO wait is through the roof. Rebooting the Opnsense VM, which normally only takes a few minutes is now taking upwards of 15-20. The entire time my IO wait sits between 50-80%.

The system has 1 disk in it that is formatted ZFS. I’ve checked dmesg, and the syslog for indications of disk errors (this feels like a failing disk) and found none. I also checked the smart statistics and they all “PASSED”.

Any pointers would be appreciated.

Example of my most recent host reboot.

Edit: I believe I’ve found the root cause of the change in performance and it was a bit of shooting myself in the foot. I’ve been experimenting with different tools for log collection and the most recent one is a SIEM tool called Wazuh. I didn’t realize that upon reboot it runs an integrity check that generates a ton of disk I/O. So when I rebooted this proxmox server, that integrity check was running on proxmox, my pihole, and (I think) opnsense concurrently. All against a single consumer grade HDD.

Thanks to everyone who responded. I really appreciate all the performance tuning guidance. I’ve also made the following changes:

  1. Added a 2nd drive (I have several of these lying around, don’t ask) converting the zfs pool into a mirror. This gives me both redundancy and should improve read performance.
  2. Configured a 2nd storage target on the same zpool with compression enabled and a 64k block size in proxmox. I then migrated the 2 VMs to that storage.
  3. Since I’m collecting logs in Wazuh I set Opnsense to use ram disks for /tmp and /var/log.

Rebooted Opensense and it was back up in 1:42 min.

  • PyrosisEnglish
    1•7 months ago

    It looks like you could also do a zpool upgrade. This will just upgrade your legacy pools to the newer zfs version. That command is fairly simple to run from terminal if you are already examining the pool.

    Edit

    Btw if you have ran pve updates it may be expecting some newer zfs flags for your pool. A pool upgrade may resolve the issue enabling the new features.

      • PyrosisEnglish
        1•7 months ago

        Upgrading a ZFS pool itself shouldn’t make a system unbootable even if an rpool (root pool) exists on it.

        That could only happen if the upgrade took a shit during a power outage or something like that. The upgrade itself usually only takes a few seconds from the command line.

        If it makes you feel better I upgraded mine with an rpool on it and it was painless. I do have a everything backed up tho so I rarely worry. However ai understand being hesitant.

        • 𝓢𝓮𝓮𝓙𝓪𝔂𝓔𝓶𝓶OPEnglish
          1•7 months ago

          I’m referring to this.

          … using grub to directly boot from ZFS - such setups are in general not safe to run zpool upgrade on!

          $ sudo proxmox-boot-tool status
Re-executing '/usr/sbin/proxmox-boot-tool' in new private mount namespace..
System currently booted with legacy bios
8357-FBD5 is configured with: grub (versions: 6.5.11-7-pve, 6.5.13-5-pve, 6.8.4-2-pve)

          Unless I’m misunderstanding the guidance.

          • PyrosisEnglish
            2•7 months ago

            It looks like you are using legacy bios. mine is using uefi with a zfs rpool

            proxmox-boot-tool status
Re-executing '/usr/sbin/proxmox-boot-tool' in new private mount namespace..
System currently booted with uefi
31FA-87E2 is configured with: uefi (versions: 6.5.11-8-pve, 6.5.13-5-pve)

            However, like with everything a method always exists to get it done. Or not if you are concerned.

            If you are interested it would look like…

            Pool Upgrade

            sudo zpool upgrade <pool_name>

            Confirm Upgrade

            sudo zpool status

            Refresh boot config

            sudo pveboot-tool refresh

            Confirm Boot configuration

            cat /boot/grub/grub.cfg

            You are looking for directives like this to see if they are indeed pointing at your existing rpool

            root=ZFS=rpool/ROOT/pve-1 boot=zfs quiet

            here is my file if it helps you compare…

            #
# DO NOT EDIT THIS FILE
#
# It is automatically generated by grub-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#

### BEGIN /etc/grub.d/000_proxmox_boot_header ###
#
# This system is booted via proxmox-boot-tool! The grub-config used when
# booting from the disks configured with proxmox-boot-tool resides on the vfat
# partitions with UUIDs listed in /etc/kernel/proxmox-boot-uuids.
# /boot/grub/grub.cfg is NOT read when booting from those disk!
### END /etc/grub.d/000_proxmox_boot_header ###

### BEGIN /etc/grub.d/00_header ###
if [ -s $prefix/grubenv ]; then
  set have_grubenv=true
  load_env
fi
if [ "${next_entry}" ] ; then
   set default="${next_entry}"
   set next_entry=
   save_env next_entry
   set boot_once=true
else
   set default="0"
fi

if [ x"${feature_menuentry_id}" = xy ]; then
  menuentry_id_option="--id"
else
  menuentry_id_option=""
fi

export menuentry_id_option

if [ "${prev_saved_entry}" ]; then
  set saved_entry="${prev_saved_entry}"
  save_env saved_entry
  set prev_saved_entry=
  save_env prev_saved_entry
  set boot_once=true
fi

function savedefault {
  if [ -z "${boot_once}" ]; then
    saved_entry="${chosen}"
    save_env saved_entry
  fi
}
function load_video {
  if [ x$feature_all_video_module = xy ]; then
    insmod all_video
  else
    insmod efi_gop
    insmod efi_uga
    insmod ieee1275_fb
    insmod vbe
    insmod vga
    insmod video_bochs
    insmod video_cirrus
  fi
}

if loadfont unicode ; then
  set gfxmode=auto
  load_video
  insmod gfxterm
  set locale_dir=$prefix/locale
  set lang=en_US
  insmod gettext
fi
terminal_output gfxterm
if [ "${recordfail}" = 1 ] ; then
  set timeout=30
else
  if [ x$feature_timeout_style = xy ] ; then
    set timeout_style=menu
    set timeout=5
  # Fallback normal timeout code in case the timeout_style feature is
  # unavailable.
  else
    set timeout=5
  fi
fi
### END /etc/grub.d/00_header ###

### BEGIN /etc/grub.d/05_debian_theme ###
set menu_color_normal=cyan/blue
set menu_color_highlight=white/blue
### END /etc/grub.d/05_debian_theme ###

### BEGIN /etc/grub.d/10_linux ###
function gfxmode {
        set gfxpayload="${1}"
}
set linux_gfx_mode=
export linux_gfx_mode
menuentry 'Proxmox VE GNU/Linux' --class proxmox --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-simple-/dev/sdc3' {
        load_video
        insmod gzio
        if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
        insmod part_gpt
        echo    'Loading Linux 6.5.13-5-pve ...'
        linux   /ROOT/pve-1@/boot/vmlinuz-6.5.13-5-pve root=ZFS=/ROOT/pve-1 ro       root=ZFS=rpool/ROOT/pve-1 boot=zfs quiet
        echo    'Loading initial ramdisk ...'
        initrd  /ROOT/pve-1@/boot/initrd.img-6.5.13-5-pve
}
submenu 'Advanced options for Proxmox VE GNU/Linux' $menuentry_id_option 'gnulinux-advanced-/dev/sdc3' {
        menuentry 'Proxmox VE GNU/Linux, with Linux 6.5.13-5-pve' --class proxmox --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-6.5.13-5-pve-advanced-/dev/sdc3' {
                load_video
                insmod gzio
                if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
                insmod part_gpt
                echo    'Loading Linux 6.5.13-5-pve ...'
                linux   /ROOT/pve-1@/boot/vmlinuz-6.5.13-5-pve root=ZFS=/ROOT/pve-1 ro       root=ZFS=rpool/ROOT/pve-1 boot=zfs quiet
                echo    'Loading initial ramdisk ...'
                initrd  /ROOT/pve-1@/boot/initrd.img-6.5.13-5-pve
        }
        menuentry 'Proxmox VE GNU/Linux, with Linux 6.5.13-5-pve (recovery mode)' --class proxmox --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-6.5.13-5-pve-recovery-/dev/sdc3' {
                load_video
                insmod gzio
                if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
                insmod part_gpt
                echo    'Loading Linux 6.5.13-5-pve ...'
                linux   /ROOT/pve-1@/boot/vmlinuz-6.5.13-5-pve root=ZFS=/ROOT/pve-1 ro single       root=ZFS=rpool/ROOT/pve-1 boot=zfs
                echo    'Loading initial ramdisk ...'
                initrd  /ROOT/pve-1@/boot/initrd.img-6.5.13-5-pve
        }
        menuentry 'Proxmox VE GNU/Linux, with Linux 6.5.11-8-pve' --class proxmox --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-6.5.11-8-pve-advanced-/dev/sdc3' {
                load_video
                insmod gzio
                if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
                insmod part_gpt
                echo    'Loading Linux 6.5.11-8-pve ...'
                linux   /ROOT/pve-1@/boot/vmlinuz-6.5.11-8-pve root=ZFS=/ROOT/pve-1 ro       root=ZFS=rpool/ROOT/pve-1 boot=zfs quiet
                echo    'Loading initial ramdisk ...'
                initrd  /ROOT/pve-1@/boot/initrd.img-6.5.11-8-pve
        }
        menuentry 'Proxmox VE GNU/Linux, with Linux 6.5.11-8-pve (recovery mode)' --class proxmox --class gnu-linux --class gnu --class os $menuentry_id_option 'gnulinux-6.5.11-8-pve-recovery-/dev/sdc3' {
                load_video
                insmod gzio
                if [ x$grub_platform = xxen ]; then insmod xzio; insmod lzopio; fi
                insmod part_gpt
                echo    'Loading Linux 6.5.11-8-pve ...'
                linux   /ROOT/pve-1@/boot/vmlinuz-6.5.11-8-pve root=ZFS=/ROOT/pve-1 ro single       root=ZFS=rpool/ROOT/pve-1 boot=zfs
                echo    'Loading initial ramdisk ...'
                initrd  /ROOT/pve-1@/boot/initrd.img-6.5.11-8-pve
        }
}

### END /etc/grub.d/10_linux ###

### BEGIN /etc/grub.d/20_linux_xen ###

### END /etc/grub.d/20_linux_xen ###

### BEGIN /etc/grub.d/20_memtest86+ ###
### END /etc/grub.d/20_memtest86+ ###

### BEGIN /etc/grub.d/30_os-prober ###
### END /etc/grub.d/30_os-prober ###

### BEGIN /etc/grub.d/30_uefi-firmware ###
menuentry 'UEFI Firmware Settings' $menuentry_id_option 'uefi-firmware' {
        fwsetup
}
### END /etc/grub.d/30_uefi-firmware ###

### BEGIN /etc/grub.d/40_custom ###
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
### END /etc/grub.d/40_custom ###

### BEGIN /etc/grub.d/41_custom ###
if [ -f  ${config_directory}/custom.cfg ]; then
  source ${config_directory}/custom.cfg
elif [ -z "${config_directory}" -a -f  $prefix/custom.cfg ]; then
  source $prefix/custom.cfg
fi
### END /etc/grub.d/41_custom ###

            You can see the lines by the linux sections.