[ceph-users] rbd mirror journal data

Jason Dillaman jdillama at redhat.com
Mon Nov 5 11:39:44 PST 2018


On Sun, Nov 4, 2018 at 11:59 PM Wei Jin <wjin.cn at gmail.com> wrote:
>
> Hi, Jason,
>
> I have a question about rbd mirroring. When enable mirroring, we observed that there are a lot of objects prefix with journal_data, thus it consumes a lot of disk space.
>
> When will these journal objects be deleted? And are there any parameters to accelerate it?
> Thanks.
>

Journal data objects should be automatically deleted when the journal
is trimmed beyond the position of the object. If you run "rbd journal
status --image <image-name>", you should be able to see the minimum
in-use set and the current active set for new journal entries:

$ rbd --cluster cluster1 journal status --image image1
minimum_set: 7
active_set: 8
registered clients:
[id=, commit_position=[positions=[[object_number=33, tag_tid=2,
entry_tid=49153], [object_number=32, tag_tid=2, entry_tid=49152],
[object_number=35, tag_tid=2, entry_tid=49151], [object_number=34,
tag_tid=2, entry_tid=49150]]], state=connected]
[id=81672c30-d735-46d4-a30a-53c221954d0e,
commit_position=[positions=[[object_number=30, tag_tid=2,
entry_tid=48034], [object_number=29, tag_tid=2, entry_tid=48033],
[object_number=28, tag_tid=2, entry_tid=48032], [object_number=31,
tag_tid=2, entry_tid=48031]]], state=connected]

$ rados --cluster cluster1 --pool rbd ls | grep journal_data | sort
journal_data.1.1029b4577f90.28
journal_data.1.1029b4577f90.29
journal_data.1.1029b4577f90.30
journal_data.1.1029b4577f90.31
journal_data.1.1029b4577f90.32
journal_data.1.1029b4577f90.33
journal_data.1.1029b4577f90.34
journal_data.1.1029b4577f90.35
<......>

$ rbd --cluster cluster1 journal status --image image1
minimum_set: 8
active_set: 8
registered clients:
[id=, commit_position=[positions=[[object_number=33, tag_tid=2,
entry_tid=49153], [object_number=32, tag_tid=2, entry_tid=49152],
[object_number=35, tag_tid=2, entry_tid=49151], [object_number=34,
tag_tid=2, entry_tid=49150]]], state=connected]
[id=81672c30-d735-46d4-a30a-53c221954d0e,
commit_position=[positions=[[object_number=33, tag_tid=2,
entry_tid=49153], [object_number=32, tag_tid=2, entry_tid=49152],
[object_number=35, tag_tid=2, entry_tid=49151], [object_number=34,
tag_tid=2, entry_tid=49150]]], state=connected]

$ rados --cluster cluster1 --pool rbd ls | grep journal_data | sort
journal_data.1.1029b4577f90.32
journal_data.1.1029b4577f90.33
journal_data.1.1029b4577f90.34
journal_data.1.1029b4577f90.35

-- 
Jason


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