Please add zfs modules to linux-raspi2

[satmandu]

The 4gb RPI4 is more than capable of handling zfs.
( Even zfs root can be enabled manually with arm64 eoan builds using a variant of the steps at https://github.com/zfsonlinux/zfs/wiki/Ubuntu-18.04-Root-on-ZFS . )

Currently one has to install zfs-dkms for zfs support, but ideally one would have zfs modules come with the standard arm64 kernel so that one does not have to recompile zfs on the pi.

Example:

uname -a
Linux rpi4 5.3.0-1011-raspi2 #12-Ubuntu SMP Fri Nov 1 09:07:06 UTC 2019 aarch64 aarch64 aarch64 GNU/Linux
@rpi4:~$ zpool status
  pool: bpool
 state: ONLINE
status: Some supported features are not enabled on the pool. The pool can
        still be used, but some features are unavailable.
action: Enable all features using 'zpool upgrade'. Once this is done,
        the pool may no longer be accessible by software that does not support
        the features. See zpool-features(5) for details.
  scan: scrub repaired 0B in 0 days 00:00:00 with 0 errors on Mon Nov 11 13:50:14 2019
config:

        NAME STATE READ WRITE CKSUM
        bpool ONLINE 0 0 0
          usb-Samsung_Flash_Drive_FIT_0309318110004882-0:0-part3 ONLINE 0 0 0

errors: No known data errors

  pool: rpool
 state: ONLINE
  scan: scrub repaired 0B in 0 days 00:01:21 with 0 errors on Mon Nov 11 13:51:39 2019
config:

        NAME STATE READ WRITE CKSUM
        rpool ONLINE 0 0 0
          sda4 ONLINE 0 0 0

errors: No known data errors

dkms status
zfs, 0.8.1, 5.3.0-1011-raspi2, aarch64: installed

@rpi4:~$ cat /proc/cpuinfo
processor : 0
BogoMIPS : 108.00
Features : fp asimd evtstrm crc32 cpuid
CPU implementer : 0x41
CPU architecture: 8
CPU variant : 0x0
CPU part : 0xd08
CPU revision : 3

processor : 1
BogoMIPS : 108.00
Features : fp asimd evtstrm crc32 cpuid
CPU implementer : 0x41
CPU architecture: 8
CPU variant : 0x0
CPU part : 0xd08
CPU revision : 3

processor : 2
BogoMIPS : 108.00
Features : fp asimd evtstrm crc32 cpuid
CPU implementer : 0x41
CPU architecture: 8
CPU variant : 0x0
CPU part : 0xd08
CPU revision : 3

processor : 3
BogoMIPS : 108.00
Features : fp asimd evtstrm crc32 cpuid
CPU implementer : 0x41
CPU architecture: 8
CPU variant : 0x0
CPU part : 0xd08
CPU revision : 3

Hardware : BCM2835
Revision : c03111
Serial : ---
Model : Raspberry Pi 4 Model B Rev 1.1
@rpi4:~$ free -m
              total used free shared buff/cache available
Mem: 3791 883 2612 18 295 2836
Swap: 4095 0 4095

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Colin Ian King (colin-king)]

The Ubuntu kernel team recommends to have at least 4GB of free memory to run ZFS on slow backing store devices for nominal performance. Since there is OS overhead (kernel, userspace processes etc) a 4GB Raspberry Pi will perform sub-optimally. Note that the document you referenced in commet #1 states:

"Computers that have less than 2 GiB of memory run ZFS slowly. 4 GiB of memory is recommended for normal performance in basic workloads. "

Once you start to add in ZFS options such as compression and/or run scrubs on a slow device it is likely you may start to see high memory pressure issues occurring. Hence we do not support ZFS unless you have at least 4GB of memory free.

[satmandu (satadru-umich)]

Thanks for the policy clarification. But as I understand it "4 GiB of memory is recommended for normal performance in basic workloads" referred to 4Gb of memory in total, not 4gb of free memory.

I'll ask again once there is a device with more than 4Gb of RAM, but FYI, since the raspberry pi may often be used for single tasks, a 4Gb ram machine might be just fine with that zfs overhead.

(I haven't seen any memory pressure issues with multiple headless 4Gb Pi4 machines running with ubuntu on zfs.)

[Peter Mathes (tammar)]

Raspberry Pi4 is already available with 8GB of memory. Now that we are way over the minimal memory requirements of ZFS, I think this topic should be reconsidered. Using zfs-dkms is a bit tedious, having the ZFS kernel modules available with the arm64 standard kernel would make the life much easier.

[Andreas Hasenack (ahasenack)]

This is fixed already:

linux-meta-raspi (5.4.0.1014.15) focal; urgency=medium

  * linux-image-raspi provides zfs modules only for arm64 (LP: #1886682)
    - [Packaging] Only provide zfs for arm64

 -- Juerg Haefliger <email address hidden> Thu, 09 Jul 2020 12:43:48 +0200

linux-meta-raspi (5.4.0.1014.14) focal; urgency=medium

  * Bump ABI 5.4.0-1014

  * Packaging resync (LP: #1786013)
    - [Packaging] resync debian/dkms-versions from main package

  * Enable ZFS for Raspberry Pi arm64 (LP: #1884110)
    - [Config] raspi: Enable zfs modules for arm64

 -- Kleber Sacilotto de Souza <email address hidden> Fri, 03 Jul 2020 17:52:25 +0200

I'm marking this as a duplicate.