Re: Hangup during scrubbing - possible solutions

2012-12-01 Thread Andrey Korolyov
On Sat, Dec 1, 2012 at 9:07 AM, Samuel Just sam.j...@inktank.com wrote:
 Just pushed a fix to next, 49f32cee647c5bd09f36ba7c9fd4f481a697b9d7.
 Let me know if it persists.  Thanks for the logs!
 -Sam


Very nice, thanks!

There is one corner case - ``on-the-fly'' upgrade works well only if
your patch applied to ``generic'' 0.54 by cherry-picking, online
upgrade to the next-dccf6ee from tagged 0.54 causes osd processes on
the upgraded nodes to fall shortly after restart with backtrace you
may see below. Offline upgrade, e.g over shutting down entire cluster,
works fine, so only one problem is a preservation of running state of
the cluster over upgrade which may confuse some users(at least ones
who runs production suites).

http://xdel.ru/downloads/ceph-log/bt-recovery-sj-patch.out.gz



 On Fri, Nov 30, 2012 at 2:04 PM, Samuel Just sam.j...@inktank.com wrote:
 Hah!  Thanks for the log, it's our handling of active_pushes.  I'll
 have a patch shortly.

 Thanks!
 -Sam

 On Fri, Nov 30, 2012 at 4:14 AM, Andrey Korolyov and...@xdel.ru wrote:
 http://xdel.ru/downloads/ceph-log/ceph-scrub-stuck.log.gz
 http://xdel.ru/downloads/ceph-log/cluster-w.log.gz

 Here, please.

 I have initiated a deep-scrub of osd.1 which was lead to forever-stuck
 I/O requests in a short time(scrub `ll do the same). Second log may be
 useful for proper timestamps, as seeks on the original may took a long
 time. Osd processes on the specific node was restarted twice - at the
 beginning to be sure all config options were applied and at the end to
 do same plus to get rid of stuck requests.


 On Wed, Nov 28, 2012 at 5:35 AM, Samuel Just sam.j...@inktank.com wrote:
 If you can reproduce it again, what we really need are the osd logs
 from the acting set of a pg stuck in scrub with
 debug osd = 20
 debug ms = 1
 debug filestore = 20.

 Thanks,
 -Sam

 On Sun, Nov 25, 2012 at 2:08 PM, Andrey Korolyov and...@xdel.ru wrote:
 On Fri, Nov 23, 2012 at 12:35 AM, Sage Weil s...@inktank.com wrote:
 On Thu, 22 Nov 2012, Andrey Korolyov wrote:
 Hi,

 In the recent versions Ceph introduces some unexpected behavior for
 the permanent connections (VM or kernel clients) - after crash
 recovery, I/O will hang on the next planned scrub on the following
 scenario:

 - launch a bunch of clients doing non-intensive writes,
 - lose one or more osd, mark them down, wait for recovery completion,
 - do a slow scrub, e.g. scrubbing one osd per 5m, inside bash script,
 or wait for ceph to do the same,
 - observe a raising number of pgs stuck in the active+clean+scrubbing
 state (they took a master role from ones which was on killed osd and
 almost surely they are being written in time of crash),
 - some time later, clients will hang hardly and ceph log introduce
 stuck(old) I/O requests.

 The only one way to return clients back without losing their I/O state
 is per-osd restart, which also will help to get rid of
 active+clean+scrubbing pgs.

 First of all, I`ll be happy to help to solve this problem by providing
 logs.

 If you can reproduce this behavior with 'debug osd = 20' and 'debug ms =
 1' logging on the OSD, that would be wonderful!


 I have tested slightly different recovery flow, please see below.
 Since there is no real harm, like frozen I/O, placement groups also
 was stuck forever on the active+clean+scrubbing state, until I
 restarted all osds (end of the log):

 http://xdel.ru/downloads/ceph-log/recover-clients-later-than-osd.txt.gz

 - start the healthy cluster
 - start persistent clients
 - add an another host with pair of OSDs, let them be in the data placement
 - wait for data to rearrange
 - [22:06 timestamp] mark OSDs out or simply kill them and wait(since I
 have an 1/2 hour delay on readjust in such case, I did ``ceph osd
 out'' manually)
 - watch for data to rearrange again
 - [22:51 timestamp] when it ends, start a manual rescrub, with
 non-zero active+clean+scrubbing-state placement groups at the end of
 process which `ll stay in this state forever until something happens

 After that, I can restart osds one per one, if I want to get rid of
 scrubbing states immediately and then do deep-scrub(if I don`t, those
 states will return at next ceph self-scrubbing) or do per-osd
 deep-scrub, if I have a lot of time. The case I have described in the
 previous message took place when I remove osd from data placement
 which existed on the moment when client(s) have started and indeed it
 is more harmful than current one(frozen I/O leads to hanging entire
 guest, for example). Since testing those flow took a lot of time, I`ll
 send logs related to this case tomorrow.

 Second question is not directly related to this problem, but I
 have thought on for a long time - is there a planned features to
 control scrub process more precisely, e.g. pg scrub rate or scheduled
 scrub, instead of current set of timeouts which of course not very
 predictable on when to run?

 Not yet.  I would be interested in hearing what kind of control/config
 options/whatever 

Re: Hangup during scrubbing - possible solutions

2012-11-30 Thread Andrey Korolyov
http://xdel.ru/downloads/ceph-log/ceph-scrub-stuck.log.gz
http://xdel.ru/downloads/ceph-log/cluster-w.log.gz

Here, please.

I have initiated a deep-scrub of osd.1 which was lead to forever-stuck
I/O requests in a short time(scrub `ll do the same). Second log may be
useful for proper timestamps, as seeks on the original may took a long
time. Osd processes on the specific node was restarted twice - at the
beginning to be sure all config options were applied and at the end to
do same plus to get rid of stuck requests.


On Wed, Nov 28, 2012 at 5:35 AM, Samuel Just sam.j...@inktank.com wrote:
 If you can reproduce it again, what we really need are the osd logs
 from the acting set of a pg stuck in scrub with
 debug osd = 20
 debug ms = 1
 debug filestore = 20.

 Thanks,
 -Sam

 On Sun, Nov 25, 2012 at 2:08 PM, Andrey Korolyov and...@xdel.ru wrote:
 On Fri, Nov 23, 2012 at 12:35 AM, Sage Weil s...@inktank.com wrote:
 On Thu, 22 Nov 2012, Andrey Korolyov wrote:
 Hi,

 In the recent versions Ceph introduces some unexpected behavior for
 the permanent connections (VM or kernel clients) - after crash
 recovery, I/O will hang on the next planned scrub on the following
 scenario:

 - launch a bunch of clients doing non-intensive writes,
 - lose one or more osd, mark them down, wait for recovery completion,
 - do a slow scrub, e.g. scrubbing one osd per 5m, inside bash script,
 or wait for ceph to do the same,
 - observe a raising number of pgs stuck in the active+clean+scrubbing
 state (they took a master role from ones which was on killed osd and
 almost surely they are being written in time of crash),
 - some time later, clients will hang hardly and ceph log introduce
 stuck(old) I/O requests.

 The only one way to return clients back without losing their I/O state
 is per-osd restart, which also will help to get rid of
 active+clean+scrubbing pgs.

 First of all, I`ll be happy to help to solve this problem by providing
 logs.

 If you can reproduce this behavior with 'debug osd = 20' and 'debug ms =
 1' logging on the OSD, that would be wonderful!


 I have tested slightly different recovery flow, please see below.
 Since there is no real harm, like frozen I/O, placement groups also
 was stuck forever on the active+clean+scrubbing state, until I
 restarted all osds (end of the log):

 http://xdel.ru/downloads/ceph-log/recover-clients-later-than-osd.txt.gz

 - start the healthy cluster
 - start persistent clients
 - add an another host with pair of OSDs, let them be in the data placement
 - wait for data to rearrange
 - [22:06 timestamp] mark OSDs out or simply kill them and wait(since I
 have an 1/2 hour delay on readjust in such case, I did ``ceph osd
 out'' manually)
 - watch for data to rearrange again
 - [22:51 timestamp] when it ends, start a manual rescrub, with
 non-zero active+clean+scrubbing-state placement groups at the end of
 process which `ll stay in this state forever until something happens

 After that, I can restart osds one per one, if I want to get rid of
 scrubbing states immediately and then do deep-scrub(if I don`t, those
 states will return at next ceph self-scrubbing) or do per-osd
 deep-scrub, if I have a lot of time. The case I have described in the
 previous message took place when I remove osd from data placement
 which existed on the moment when client(s) have started and indeed it
 is more harmful than current one(frozen I/O leads to hanging entire
 guest, for example). Since testing those flow took a lot of time, I`ll
 send logs related to this case tomorrow.

 Second question is not directly related to this problem, but I
 have thought on for a long time - is there a planned features to
 control scrub process more precisely, e.g. pg scrub rate or scheduled
 scrub, instead of current set of timeouts which of course not very
 predictable on when to run?

 Not yet.  I would be interested in hearing what kind of control/config
 options/whatever you (and others) would like to see!

 Of course it will be awesome to have any determined scheduler or at
 least an option to disable automated scrubbing, since it is not very
 determined in time and deep-scrub eating a lot of I/O if command
 issued against entire OSD. Rate limiting is not in the first place, at
 least it may be recreated in external script, but for those who prefer
 to leave control to Ceph, it may be very useful.

 Thanks!
 --
 To unsubscribe from this list: send the line unsubscribe ceph-devel in
 the body of a message to majord...@vger.kernel.org
 More majordomo info at  http://vger.kernel.org/majordomo-info.html
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Re: Hangup during scrubbing - possible solutions

2012-11-30 Thread Samuel Just
Hah!  Thanks for the log, it's our handling of active_pushes.  I'll
have a patch shortly.

Thanks!
-Sam

On Fri, Nov 30, 2012 at 4:14 AM, Andrey Korolyov and...@xdel.ru wrote:
 http://xdel.ru/downloads/ceph-log/ceph-scrub-stuck.log.gz
 http://xdel.ru/downloads/ceph-log/cluster-w.log.gz

 Here, please.

 I have initiated a deep-scrub of osd.1 which was lead to forever-stuck
 I/O requests in a short time(scrub `ll do the same). Second log may be
 useful for proper timestamps, as seeks on the original may took a long
 time. Osd processes on the specific node was restarted twice - at the
 beginning to be sure all config options were applied and at the end to
 do same plus to get rid of stuck requests.


 On Wed, Nov 28, 2012 at 5:35 AM, Samuel Just sam.j...@inktank.com wrote:
 If you can reproduce it again, what we really need are the osd logs
 from the acting set of a pg stuck in scrub with
 debug osd = 20
 debug ms = 1
 debug filestore = 20.

 Thanks,
 -Sam

 On Sun, Nov 25, 2012 at 2:08 PM, Andrey Korolyov and...@xdel.ru wrote:
 On Fri, Nov 23, 2012 at 12:35 AM, Sage Weil s...@inktank.com wrote:
 On Thu, 22 Nov 2012, Andrey Korolyov wrote:
 Hi,

 In the recent versions Ceph introduces some unexpected behavior for
 the permanent connections (VM or kernel clients) - after crash
 recovery, I/O will hang on the next planned scrub on the following
 scenario:

 - launch a bunch of clients doing non-intensive writes,
 - lose one or more osd, mark them down, wait for recovery completion,
 - do a slow scrub, e.g. scrubbing one osd per 5m, inside bash script,
 or wait for ceph to do the same,
 - observe a raising number of pgs stuck in the active+clean+scrubbing
 state (they took a master role from ones which was on killed osd and
 almost surely they are being written in time of crash),
 - some time later, clients will hang hardly and ceph log introduce
 stuck(old) I/O requests.

 The only one way to return clients back without losing their I/O state
 is per-osd restart, which also will help to get rid of
 active+clean+scrubbing pgs.

 First of all, I`ll be happy to help to solve this problem by providing
 logs.

 If you can reproduce this behavior with 'debug osd = 20' and 'debug ms =
 1' logging on the OSD, that would be wonderful!


 I have tested slightly different recovery flow, please see below.
 Since there is no real harm, like frozen I/O, placement groups also
 was stuck forever on the active+clean+scrubbing state, until I
 restarted all osds (end of the log):

 http://xdel.ru/downloads/ceph-log/recover-clients-later-than-osd.txt.gz

 - start the healthy cluster
 - start persistent clients
 - add an another host with pair of OSDs, let them be in the data placement
 - wait for data to rearrange
 - [22:06 timestamp] mark OSDs out or simply kill them and wait(since I
 have an 1/2 hour delay on readjust in such case, I did ``ceph osd
 out'' manually)
 - watch for data to rearrange again
 - [22:51 timestamp] when it ends, start a manual rescrub, with
 non-zero active+clean+scrubbing-state placement groups at the end of
 process which `ll stay in this state forever until something happens

 After that, I can restart osds one per one, if I want to get rid of
 scrubbing states immediately and then do deep-scrub(if I don`t, those
 states will return at next ceph self-scrubbing) or do per-osd
 deep-scrub, if I have a lot of time. The case I have described in the
 previous message took place when I remove osd from data placement
 which existed on the moment when client(s) have started and indeed it
 is more harmful than current one(frozen I/O leads to hanging entire
 guest, for example). Since testing those flow took a lot of time, I`ll
 send logs related to this case tomorrow.

 Second question is not directly related to this problem, but I
 have thought on for a long time - is there a planned features to
 control scrub process more precisely, e.g. pg scrub rate or scheduled
 scrub, instead of current set of timeouts which of course not very
 predictable on when to run?

 Not yet.  I would be interested in hearing what kind of control/config
 options/whatever you (and others) would like to see!

 Of course it will be awesome to have any determined scheduler or at
 least an option to disable automated scrubbing, since it is not very
 determined in time and deep-scrub eating a lot of I/O if command
 issued against entire OSD. Rate limiting is not in the first place, at
 least it may be recreated in external script, but for those who prefer
 to leave control to Ceph, it may be very useful.

 Thanks!
 --
 To unsubscribe from this list: send the line unsubscribe ceph-devel in
 the body of a message to majord...@vger.kernel.org
 More majordomo info at  http://vger.kernel.org/majordomo-info.html
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Re: Hangup during scrubbing - possible solutions

2012-11-30 Thread Samuel Just
Just pushed a fix to next, 49f32cee647c5bd09f36ba7c9fd4f481a697b9d7.
Let me know if it persists.  Thanks for the logs!
-Sam

On Fri, Nov 30, 2012 at 2:04 PM, Samuel Just sam.j...@inktank.com wrote:
 Hah!  Thanks for the log, it's our handling of active_pushes.  I'll
 have a patch shortly.

 Thanks!
 -Sam

 On Fri, Nov 30, 2012 at 4:14 AM, Andrey Korolyov and...@xdel.ru wrote:
 http://xdel.ru/downloads/ceph-log/ceph-scrub-stuck.log.gz
 http://xdel.ru/downloads/ceph-log/cluster-w.log.gz

 Here, please.

 I have initiated a deep-scrub of osd.1 which was lead to forever-stuck
 I/O requests in a short time(scrub `ll do the same). Second log may be
 useful for proper timestamps, as seeks on the original may took a long
 time. Osd processes on the specific node was restarted twice - at the
 beginning to be sure all config options were applied and at the end to
 do same plus to get rid of stuck requests.


 On Wed, Nov 28, 2012 at 5:35 AM, Samuel Just sam.j...@inktank.com wrote:
 If you can reproduce it again, what we really need are the osd logs
 from the acting set of a pg stuck in scrub with
 debug osd = 20
 debug ms = 1
 debug filestore = 20.

 Thanks,
 -Sam

 On Sun, Nov 25, 2012 at 2:08 PM, Andrey Korolyov and...@xdel.ru wrote:
 On Fri, Nov 23, 2012 at 12:35 AM, Sage Weil s...@inktank.com wrote:
 On Thu, 22 Nov 2012, Andrey Korolyov wrote:
 Hi,

 In the recent versions Ceph introduces some unexpected behavior for
 the permanent connections (VM or kernel clients) - after crash
 recovery, I/O will hang on the next planned scrub on the following
 scenario:

 - launch a bunch of clients doing non-intensive writes,
 - lose one or more osd, mark them down, wait for recovery completion,
 - do a slow scrub, e.g. scrubbing one osd per 5m, inside bash script,
 or wait for ceph to do the same,
 - observe a raising number of pgs stuck in the active+clean+scrubbing
 state (they took a master role from ones which was on killed osd and
 almost surely they are being written in time of crash),
 - some time later, clients will hang hardly and ceph log introduce
 stuck(old) I/O requests.

 The only one way to return clients back without losing their I/O state
 is per-osd restart, which also will help to get rid of
 active+clean+scrubbing pgs.

 First of all, I`ll be happy to help to solve this problem by providing
 logs.

 If you can reproduce this behavior with 'debug osd = 20' and 'debug ms =
 1' logging on the OSD, that would be wonderful!


 I have tested slightly different recovery flow, please see below.
 Since there is no real harm, like frozen I/O, placement groups also
 was stuck forever on the active+clean+scrubbing state, until I
 restarted all osds (end of the log):

 http://xdel.ru/downloads/ceph-log/recover-clients-later-than-osd.txt.gz

 - start the healthy cluster
 - start persistent clients
 - add an another host with pair of OSDs, let them be in the data placement
 - wait for data to rearrange
 - [22:06 timestamp] mark OSDs out or simply kill them and wait(since I
 have an 1/2 hour delay on readjust in such case, I did ``ceph osd
 out'' manually)
 - watch for data to rearrange again
 - [22:51 timestamp] when it ends, start a manual rescrub, with
 non-zero active+clean+scrubbing-state placement groups at the end of
 process which `ll stay in this state forever until something happens

 After that, I can restart osds one per one, if I want to get rid of
 scrubbing states immediately and then do deep-scrub(if I don`t, those
 states will return at next ceph self-scrubbing) or do per-osd
 deep-scrub, if I have a lot of time. The case I have described in the
 previous message took place when I remove osd from data placement
 which existed on the moment when client(s) have started and indeed it
 is more harmful than current one(frozen I/O leads to hanging entire
 guest, for example). Since testing those flow took a lot of time, I`ll
 send logs related to this case tomorrow.

 Second question is not directly related to this problem, but I
 have thought on for a long time - is there a planned features to
 control scrub process more precisely, e.g. pg scrub rate or scheduled
 scrub, instead of current set of timeouts which of course not very
 predictable on when to run?

 Not yet.  I would be interested in hearing what kind of control/config
 options/whatever you (and others) would like to see!

 Of course it will be awesome to have any determined scheduler or at
 least an option to disable automated scrubbing, since it is not very
 determined in time and deep-scrub eating a lot of I/O if command
 issued against entire OSD. Rate limiting is not in the first place, at
 least it may be recreated in external script, but for those who prefer
 to leave control to Ceph, it may be very useful.

 Thanks!
 --
 To unsubscribe from this list: send the line unsubscribe ceph-devel in
 the body of a message to majord...@vger.kernel.org
 More majordomo info at  http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this 

Re: Hangup during scrubbing - possible solutions

2012-11-25 Thread Andrey Korolyov
On Fri, Nov 23, 2012 at 12:35 AM, Sage Weil s...@inktank.com wrote:
 On Thu, 22 Nov 2012, Andrey Korolyov wrote:
 Hi,

 In the recent versions Ceph introduces some unexpected behavior for
 the permanent connections (VM or kernel clients) - after crash
 recovery, I/O will hang on the next planned scrub on the following
 scenario:

 - launch a bunch of clients doing non-intensive writes,
 - lose one or more osd, mark them down, wait for recovery completion,
 - do a slow scrub, e.g. scrubbing one osd per 5m, inside bash script,
 or wait for ceph to do the same,
 - observe a raising number of pgs stuck in the active+clean+scrubbing
 state (they took a master role from ones which was on killed osd and
 almost surely they are being written in time of crash),
 - some time later, clients will hang hardly and ceph log introduce
 stuck(old) I/O requests.

 The only one way to return clients back without losing their I/O state
 is per-osd restart, which also will help to get rid of
 active+clean+scrubbing pgs.

 First of all, I`ll be happy to help to solve this problem by providing
 logs.

 If you can reproduce this behavior with 'debug osd = 20' and 'debug ms =
 1' logging on the OSD, that would be wonderful!


I have tested slightly different recovery flow, please see below.
Since there is no real harm, like frozen I/O, placement groups also
was stuck forever on the active+clean+scrubbing state, until I
restarted all osds (end of the log):

http://xdel.ru/downloads/ceph-log/recover-clients-later-than-osd.txt.gz

- start the healthy cluster
- start persistent clients
- add an another host with pair of OSDs, let them be in the data placement
- wait for data to rearrange
- [22:06 timestamp] mark OSDs out or simply kill them and wait(since I
have an 1/2 hour delay on readjust in such case, I did ``ceph osd
out'' manually)
- watch for data to rearrange again
- [22:51 timestamp] when it ends, start a manual rescrub, with
non-zero active+clean+scrubbing-state placement groups at the end of
process which `ll stay in this state forever until something happens

After that, I can restart osds one per one, if I want to get rid of
scrubbing states immediately and then do deep-scrub(if I don`t, those
states will return at next ceph self-scrubbing) or do per-osd
deep-scrub, if I have a lot of time. The case I have described in the
previous message took place when I remove osd from data placement
which existed on the moment when client(s) have started and indeed it
is more harmful than current one(frozen I/O leads to hanging entire
guest, for example). Since testing those flow took a lot of time, I`ll
send logs related to this case tomorrow.

 Second question is not directly related to this problem, but I
 have thought on for a long time - is there a planned features to
 control scrub process more precisely, e.g. pg scrub rate or scheduled
 scrub, instead of current set of timeouts which of course not very
 predictable on when to run?

 Not yet.  I would be interested in hearing what kind of control/config
 options/whatever you (and others) would like to see!

Of course it will be awesome to have any determined scheduler or at
least an option to disable automated scrubbing, since it is not very
determined in time and deep-scrub eating a lot of I/O if command
issued against entire OSD. Rate limiting is not in the first place, at
least it may be recreated in external script, but for those who prefer
to leave control to Ceph, it may be very useful.

Thanks!
--
To unsubscribe from this list: send the line unsubscribe ceph-devel in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html


Hangup during scrubbing - possible solutions

2012-11-22 Thread Andrey Korolyov
Hi,

In the recent versions Ceph introduces some unexpected behavior for
the permanent connections (VM or kernel clients) - after crash
recovery, I/O will hang on the next planned scrub on the following
scenario:

- launch a bunch of clients doing non-intensive writes,
- lose one or more osd, mark them down, wait for recovery completion,
- do a slow scrub, e.g. scrubbing one osd per 5m, inside bash script,
or wait for ceph to do the same,
- observe a raising number of pgs stuck in the active+clean+scrubbing
state (they took a master role from ones which was on killed osd and
almost surely they are being written in time of crash),
- some time later, clients will hang hardly and ceph log introduce
stuck(old) I/O requests.

The only one way to return clients back without losing their I/O state
is per-osd restart, which also will help to get rid of
active+clean+scrubbing pgs.

First of all, I`ll be happy to help to solve this problem by providing
logs. Second question is not directly related to this problem, but I
have thought on for a long time - is there a planned features to
control scrub process more precisely, e.g. pg scrub rate or scheduled
scrub, instead of current set of timeouts which of course not very
predictable on when to run?

Thanks!
--
To unsubscribe from this list: send the line unsubscribe ceph-devel in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html


Re: Hangup during scrubbing - possible solutions

2012-11-22 Thread Sage Weil
On Thu, 22 Nov 2012, Andrey Korolyov wrote:
 Hi,
 
 In the recent versions Ceph introduces some unexpected behavior for
 the permanent connections (VM or kernel clients) - after crash
 recovery, I/O will hang on the next planned scrub on the following
 scenario:
 
 - launch a bunch of clients doing non-intensive writes,
 - lose one or more osd, mark them down, wait for recovery completion,
 - do a slow scrub, e.g. scrubbing one osd per 5m, inside bash script,
 or wait for ceph to do the same,
 - observe a raising number of pgs stuck in the active+clean+scrubbing
 state (they took a master role from ones which was on killed osd and
 almost surely they are being written in time of crash),
 - some time later, clients will hang hardly and ceph log introduce
 stuck(old) I/O requests.
 
 The only one way to return clients back without losing their I/O state
 is per-osd restart, which also will help to get rid of
 active+clean+scrubbing pgs.
 
 First of all, I`ll be happy to help to solve this problem by providing
 logs.

If you can reproduce this behavior with 'debug osd = 20' and 'debug ms = 
1' logging on the OSD, that would be wonderful!

 Second question is not directly related to this problem, but I
 have thought on for a long time - is there a planned features to
 control scrub process more precisely, e.g. pg scrub rate or scheduled
 scrub, instead of current set of timeouts which of course not very
 predictable on when to run?

Not yet.  I would be interested in hearing what kind of control/config 
options/whatever you (and others) would like to see!

Thanks-
sage
--
To unsubscribe from this list: send the line unsubscribe ceph-devel in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html