Default crush map should use straw2

Bug #1836092 reported by Sandor Zeestraten on 2019-07-10
8
This bug affects 1 person
Affects Status Importance Assigned to Milestone
OpenStack ceph-mon charm
Medium
Chris MacNaughton
charms.ceph
Medium
Chris MacNaughton

Bug Description

The default crush algorithm used by the charms is `straw`, while `straw2` was the new default in the Hammer release (http://docs.ceph.com/docs/mimic/rados/operations/crush-map/#hammer-crush-v4).

Deployments with `straw` will need to migrate to `straw2` in order to utilise newer features in Luminous such as the mgr balance plugin (https://ceph-users.ceph.narkive.com/fFMZOiMg/error-creating-compat-weight-set-with-mgr-balancer-plugin).

Migration impact:
Changing a bucket type from straw to straw2 will result in a reasonably small amount of data movement, depending on how much the bucket item weights vary from each other. When the weights are all the same no data will move, and when item weights vary significantly there will be more movement.

Offending line: https://github.com/openstack/charm-ceph-mon/blob/master/lib/ceph/crush_utils.py#L27

description: updated
James Page (james-page) on 2019-07-18
Changed in charm-ceph-mon:
status: New → Triaged
Changed in charms.ceph:
status: New → Triaged
Changed in charm-ceph-mon:
importance: Undecided → Medium
Changed in charms.ceph:
importance: Undecided → Medium
assignee: nobody → Chris MacNaughton (chris.macnaughton)
Changed in charm-ceph-mon:
assignee: nobody → Chris MacNaughton (chris.macnaughton)
milestone: none → 19.10
Changed in charm-ceph-mon:
status: Triaged → In Progress

Reviewed: https://review.opendev.org/670232
Committed: https://git.openstack.org/cgit/openstack/charms.ceph/commit/?id=5f095b59cd078a76aeeca22cb5a7b34f9fae9e67
Submitter: Zuul
Branch: master

commit 5f095b59cd078a76aeeca22cb5a7b34f9fae9e67
Author: Chris MacNaughton <email address hidden>
Date: Thu Jul 11 08:00:06 2019 +0200

    Update default CRUSH algorithm to straw2

    straw2 has been the default CRUSH algorithm since hammer
    and Ubuntu Xenial ships with Jewel, meaning that straw2
    is the default in all current LTS releases.

    Change-Id: I6fa4072eb33d763aca5721ee9fdd30b60d468a44
    Closes-Bug: #1836092

Changed in charms.ceph:
status: Triaged → Fix Released
To post a comment you must log in.
This report contains Public information  Edit
Everyone can see this information.

Other bug subscribers