Ubuntu
zfs-linux package

ZFS: Set elevator=noop on disks in the root pool

Bug #1550301 reported by Richard Laager on 2016-02-26

This bug affects 1 person

	Status	Importance	Assigned to
zfs-linux (Ubuntu)	Won't Fix	Medium	Colin Ian King
Xenial	Fix Released	Medium	Colin Ian King
Zesty	Won't Fix	Undecided	Unassigned

Bug Description

ZFS-on-Linux has its own I/O scheduler, so it sets the "noop" elevator on whole disks used in a pool. https://github.com/zfsonlinux/zfs/issues/90

It does not set the scheduler for a disk if a partition is used in a pool out of respect for the possibility that there are non-ZFS partitions on the same disk. https://github.com/zfsonlinux/zfs/issues/152

For regular pools, the recommendation is to use whole disks. For a root pools, it's just the opposite. The typical case is that partitions are used. And, for root pools, it is unlikely that the same disks have non-ZFS filesystems.

The debdiff in comment #5 applies cleanly to the latest package and functions correctly. This is an important change for root-on-ZFS users. It has no effect on non-root-on-ZFS installs, because the code is only in the zfs-initramfs package.

See original description

Tags:

Revision history for this message

Richard Laager (rlaager) wrote on 2016-02-26:

zfs-scheduler.debdiff Edit (1.7 KiB, text/plain)

description:	updated
description:	updated

Revision history for this message

Ubuntu Foundations Team Bug Bot (crichton) wrote on 2016-02-26:

The attachment "zfs-scheduler.debdiff" seems to be a debdiff. The ubuntu-sponsors team has been subscribed to the bug report so that they can review and hopefully sponsor the debdiff. If the attachment isn't a patch, please remove the "patch" flag from the attachment, remove the "patch" tag, and if you are member of the ~ubuntu-sponsors, unsubscribe the team.

[This is an automated message performed by a Launchpad user owned by ~brian-murray, for any issue please contact him.]

tags:

added: patch

Mathew Hodson (mhodson) on 2016-02-28

Changed in zfs-linux (Ubuntu):
importance:	Undecided → Low

Revision history for this message

Richard Laager (rlaager) wrote on 2016-03-21:

This requires the -L flag to zpool status. It sounds like ZoL 0.6.5.6 will land in Xenial, so then this is good to go at that time too.

Revision history for this message

Richard Laager (rlaager) wrote on 2016-04-08:

ZoL 0.6.5.6 has landed, so this should be good to go. Note that it only affects zfs-initramfs. It doesn't affect any other use of ZFS.

Revision history for this message

Richard Laager (rlaager) wrote on 2016-04-12:

Refreshed & re-tested debdiff against 0.6.5.6. Edit (1.7 KiB, text/plain)

description:	updated
summary:	- ZFS: Set elevator=noop on disks in the root pool + [FFe] ZFS: Set elevator=noop on disks in the root pool

Revision history for this message

Martin Pitt (pitti) wrote on 2016-04-13:

I'd call this a bug fix. Adjusting title and unsubscribing release team. Please go ahead.

summary:

- [FFe] ZFS: Set elevator=noop on disks in the root pool
+ ZFS: Set elevator=noop on disks in the root pool

Revision history for this message

Colin Ian King (colin-king) wrote on 2016-04-13:

I'll get this applied and uploaded today

Revision history for this message

Launchpad Janitor (janitor) wrote on 2016-04-13:

This bug was fixed in the package zfs-linux - 0.6.5.6-0ubuntu8

---------------
zfs-linux (0.6.5.6-0ubuntu8) xenial; urgency=medium

  [ Richard Laager ]
  * zfs-initramfs: Set elevator=noop on disks used by the root pool.
    (LP: #1550301)

-- Colin Ian King <email address hidden> Wed, 13 Apr 2016 11:44:39 +0100

Changed in zfs-linux (Ubuntu):
status:	New → Fix Released

Revision history for this message

Richard Laager (rlaager) wrote on 2017-04-23:

This has regressed in Zesty, because someone replaced the zfs-initramfs script.

Changed in zfs-linux (Ubuntu):
status:	Fix Released → Confirmed

Richard Laager (rlaager) on 2017-04-23

tags:

added: regression-release zesty
removed: patch

Colin Ian King (colin-king) on 2017-05-22

Changed in zfs-linux (Ubuntu):
status:	Confirmed → In Progress
assignee:	nobody → Colin Ian King (colin-king)
importance:	Low → Medium

Eric Desrochers (slashd) on 2017-08-04

Changed in zfs-linux (Ubuntu Xenial):
status:	New → Fix Released
importance:	Undecided → Medium
assignee:	nobody → Colin Ian King (colin-king)
Changed in zfs-linux (Ubuntu Zesty):
status:	New → Confirmed

Revision history for this message

Simon Quigley (tsimonq2) wrote on 2017-08-30:

#10

Unsubscribing ~ubuntu-sponsors as there's nothing left to do. If that is incorrect, please feel free to resubscribe.

Revision history for this message

Colin Ian King (colin-king) wrote on 2017-09-19:

#11

Since this affects root on ZFS and the original patch no longer applies (and ZFS on root) is not currently supported, I am reluctantly going to close is issue. If a clean fix for ZFS on root for newer Zesty+ initramfs scripts is available I am happy to re-apply them for newer releases. However, I am not going to forward port the original changes since the delta is too large and I am not able to test these (as we don't have ZFS on root by default).