From: David Zafman <dzafman@redhat.com>
To: Wei-Chung Cheng <freeze.vicente.cheng@gmail.com>,
Sage Weil <sweil@redhat.com>
Cc: Loic Dachary <loic@dachary.org>,
Ceph Development <ceph-devel@vger.kernel.org>
Subject: Re: new OSD re-using old OSD id fails to boot
Date: Wed, 9 Dec 2015 11:55:18 -0800 [thread overview]
Message-ID: <56688726.5000609@redhat.com> (raw)
In-Reply-To: <CABF_e-FC7TGFw9=_zEB2-GX=3EOcoX-oc6=L=NPbuipBRo+atg@mail.gmail.com>
On 12/9/15 2:39 AM, Wei-Chung Cheng wrote:
> Hi Loic,
>
> I try to reproduce this problem on my CentOS7.
> I can not do the same issue.
> This is my version:
> ceph version 10.0.0-928-g8eb0ed1 (8eb0ed1dcda9ee6180a06ee6a4415b112090c534)
> Would you describe more detail?
>
>
> Hi David, Sage,
>
> In most of time, when we found the osd failure, the OSD is already in
> `out` state.
> It could not avoid the redundant data movement unless we could set the
> osd noout when failure.
> Is it right? (Means if OSD go into `out` state, it will make some
> redundant data movement)
Yes, one case would be that during the 5 minute down window of an OSD
disk failure, the noout flag can be set if a spare disk is available.
Another scenario would be a bad SMART status or noticing EIO errors from
a disk prompting a replacement. So if a spare disk is already installed
or you have hot swappable drives, it would be nice to replace the drive
and let recovery copy back all the data that should be there. Using
noout would be critical to this effort.
I don't understand why Sage suggests below that a down+out phase would
be required during the replacement.
>
> Could we try the traditional spare behavior? (Set some disks backup
> and auto replace the broken device?)
>
> That can replace the failure osd before it go into the `out` state.
> Or we could always set the osd noout?
>
> In fact, I think these is a different problems between David and Loic.
> (these two problems are the same import :p
>
> If you have any problems, feel free to let me know.
>
> thanks!!
> vicente
>
>
> 2015-12-09 10:50 GMT+08:00 Sage Weil <sweil@redhat.com>:
>> On Tue, 8 Dec 2015, David Zafman wrote:
>>> Remember I really think we want a disk replacement feature that would retain
>>> the OSD id so that it avoids unnecessary data movement. See tracker
>>> http://tracker.ceph.com/issues/13732
>> Yeah, I totally agree. We just need to form an opinion on how... probably
>> starting with the user experience. Ideally we'd go from up + in to down +
>> in to down + out, then pull the drive and replace, and then initialize a
Here ^^^^^^^^^^^^
>> new OSD with the same id... and journal partition. Something like
>>
>> ceph-disk recreate id=N uuid=U <osd device path>
>>
>> I.e., it could use the uuid (which the cluster has in the OSDMap) to find
>> (and re-use) the journal device.
>>
>> For a journal failure it'd probably be different.. but maybe not?
>>
>> Any other ideas?
>>
>> sage
>> --
>> To unsubscribe from this list: send the line "unsubscribe ceph-devel" in
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next prev parent reply other threads:[~2015-12-09 19:55 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-05 16:49 new OSD re-using old OSD id fails to boot Loic Dachary
2015-12-09 1:13 ` David Zafman
2015-12-09 2:50 ` Sage Weil
2015-12-09 10:39 ` Wei-Chung Cheng
2015-12-09 13:08 ` Loic Dachary
2015-12-09 14:00 ` Sage Weil
2015-12-09 19:55 ` David Zafman [this message]
2015-12-09 20:08 ` Sage Weil
2015-12-09 13:06 ` Loic Dachary
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