Discussion:
Is there a "set pool readonly" command?
(too old to reply)
Nico Schottelius
2018-02-11 14:46:42 UTC
Permalink
Hello,

we have one pool, in which about 10 disks failed last week (fortunately
mostly sequentially), which now has now some pgs that are only left on
one disk.

Is there a command to set one pool into "read-only" mode or even
"recovery io-only" mode so that the only thing same is doing is
recovering and no client i/o will disturb that process?

Best,

Nico



--
Modern, affordable, Swiss Virtual Machines. Visit www.datacenterlight.ch
David Turner
2018-02-11 17:45:13 UTC
Permalink
If you set min_size to 2 or more, it will disable reads and writes to the
pool by blocking requests. Min_size is the minimum copies of a PG that need
to be online to allow it to the data. If you only have 1 copy, then it will
prevent io. It's not a flag you can set on the pool, but it should work
out. If you have size=3, then min_size=3 should block most io until the
pool is almost fully backfilled.
Post by Nico Schottelius
Hello,
we have one pool, in which about 10 disks failed last week (fortunately
mostly sequentially), which now has now some pgs that are only left on
one disk.
Is there a command to set one pool into "read-only" mode or even
"recovery io-only" mode so that the only thing same is doing is
recovering and no client i/o will disturb that process?
Best,
Nico
--
Modern, affordable, Swiss Virtual Machines. Visit www.datacenterlight.ch
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David Turner
2018-02-12 19:32:24 UTC
Permalink
The pause flag also pauses recovery traffic. It is literally a flag to
stop anything and everything in the cluster so you can get an expert in to
prevent something even worse from happening.
I do know that there is a pause flag in Ceph.
What I do not know is if that also pauses recovery traffic, in addition to
client traffic.
Also worth mentioning, this is a cluster-wide flag, not a pool level flag.
Reed
If you set min_size to 2 or more, it will disable reads and writes to the
pool by blocking requests. Min_size is the minimum copies of a PG that need
to be online to allow it to the data. If you only have 1 copy, then it will
prevent io. It's not a flag you can set on the pool, but it should work
out. If you have size=3, then min_size=3 should block most io until the
pool is almost fully backfilled.
On Sun, Feb 11, 2018, 9:46 AM Nico Schottelius <
Post by Nico Schottelius
Hello,
we have one pool, in which about 10 disks failed last week (fortunately
mostly sequentially), which now has now some pgs that are only left on
one disk.
Is there a command to set one pool into "read-only" mode or even
"recovery io-only" mode so that the only thing same is doing is
recovering and no client i/o will disturb that process?
Best,
Nico
--
Modern, affordable, Swiss Virtual Machines. Visit www.datacenterlight.ch
_______________________________________________
ceph-users mailing list
http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
_______________________________________________
ceph-users mailing list
http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
c***@elchaka.de
2018-02-14 21:59:34 UTC
Permalink
Post by David Turner
The pause flag also pauses recovery traffic. It is literally a flag to
stop anything and everything in the cluster so you can get an expert in to
prevent something even worse from happening.
I am not sure but a few years ago (2/3) i had a look in calamarie and there was a flag which could be set to stop client io only...

Someone out there who is using calamarie Today and could give a short response?

- Mehmet
Post by David Turner
I do know that there is a pause flag in Ceph.
What I do not know is if that also pauses recovery traffic, in
addition to
client traffic.
Also worth mentioning, this is a cluster-wide flag, not a pool level
flag.
Reed
If you set min_size to 2 or more, it will disable reads and writes to
the
pool by blocking requests. Min_size is the minimum copies of a PG
that need
to be online to allow it to the data. If you only have 1 copy, then
it will
prevent io. It's not a flag you can set on the pool, but it should
work
out. If you have size=3, then min_size=3 should block most io until
the
pool is almost fully backfilled.
On Sun, Feb 11, 2018, 9:46 AM Nico Schottelius <
Post by Nico Schottelius
Hello,
we have one pool, in which about 10 disks failed last week
(fortunately
Post by Nico Schottelius
mostly sequentially), which now has now some pgs that are only left
on
Post by Nico Schottelius
one disk.
Is there a command to set one pool into "read-only" mode or even
"recovery io-only" mode so that the only thing same is doing is
recovering and no client i/o will disturb that process?
Best,
Nico
--
Modern, affordable, Swiss Virtual Machines. Visit
www.datacenterlight.ch
Post by Nico Schottelius
_______________________________________________
ceph-users mailing list
http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
_______________________________________________
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http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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