Greetings
Just a follow up on the resolution of this issue.
Restarting ceph-osd on one of the nodes solved the problem of the
stuck unclean pgs.
Thanks,
JR
On 9/9/2014 2:24 AM, Christian Balzer wrote:
>
> Hello,
>
> On Tue, 09 Sep 2014 01:25:17 -0400 JR wrote:
>
>> Greetings
>>
>> After running for a couple of hours, my attempt to re-balance a
>> near ful disk has stopped with a stuck unclean error:
>>
> Which is exactly what I warned you about below and what you should
> have also taken away from fully reading the "Uneven OSD usage"
> thread.
>
> This also should hammer my previous point about your current
> cluster size/utilization home. Even with a better (don't expect
> perfect) data distribution, loss of one node might well find you
> with a full OSD again.
>
>> root@osd45:~# ceph -s cluster
>> c8122868-27af-11e4-b570-52540004010f health HEALTH_WARN 6 pgs
>> backfilling; 6 pgs stuck unclean; recovery 13086/1158268
>> degraded (1.130%) monmap e1: 3 mons at
>> {osd42=10.7.7.142:6789/0,osd43=10.7.7.143:6789/0,osd45=10.7.7.145:6789/0},
>>
>>
>>
election epoch 80, quorum 0,1,2 osd42,osd43,osd45
>> osdmap e723: 8 osds: 8 up, 8 in pgmap v543113: 640 pgs: 634
>> active+clean, 6 active+remapped+backfilling; 2222 GB data, 2239
>> GB used, 1295 GB / 3535 GB avail; 8268B/s wr, 0op/s;
>> 13086/1158268 degraded (1.130%) mdsmap e63: 1/1/1 up
>> {0=osd42=up:active}, 3 up:standby
>>
> From what I've read in the past the way forward here is to
> increase the full ratio setting so it can finish the recovery. Or
> add more OSDs, at least temporarily. See:
> http://ceph.com/docs/master/rados/configuration/mon-config-ref/#storage-capacity
>
>
>
Read that and apply that knowledge to your cluster, I personally
> wouldn't deploy it in this state.
>
> Once the recovery is finished I'd proceed cautiously, see below.
>
>>
>> The sequence of events today that led to this were:
>>
>> # starting state: pg_num/pgp_num == 64 ceph osd pool set rbd
>> pg_num 128 ceph osd pool set rbd pgp_num 128 # there was a
>> warning thrown up (which I've lost) and which left pgg_num == 64
>> # nothing happens since pgp_num was inadvertently not raised
>> ceph osd reweight-by-utilization # data moves from one osd on a
>> host to another osd on same host ceph osd reweight 7 1 # data
>> moves back to roughly what it had been
> Never mind the the lack of PGs to play with, manually lowering the
> weight of the fullest OSD (in small steps) at this time might have
> given you at least a more level playing field.
>
>> ceph osd pool set volumes pg_num 192 ceph osd pool set volumes
>> pgp_num 192 # data moves successfully
> This would have been the time to check what actually happened and
> if things improved or not (just adding PGs/PGPs might not be
> enough) and again to manually reweight overly full OSDs.
>
>> ceph osd pool set rbd pg_num 192 ceph osd pool set rbd pgp_num
>> 192 # data stuck
>>
> Baby steps. As in, applying the rise to 128 PGPs first. But I
> guess you would have run into the full OSD either way w/o
> reweighting things between steps.
>
>> googling (nowadays known as research) reveals that these might be
>> helpful:
>>
>> - ceph osd crush tunables optimal
> Yes, this might help. Not sure if that works with dumpling, but as
> I already mentioned dumpling doesn't support "chooseleaf_vary_r".
> And hashspool. And while the data movement caused by this probably
> will result in a better balanced cluster (again, with too little
> PGs it will still do poorly), in the process of getting there it
> might still run into a full OSD scenario.
>
>> - setting crush weights to 1
>>
> Dunno about then one, my crush weights were 1 when I deployed
> things manually for the first time, the size of the OSD for the
> 2nd manual deployment and ceph-deploy also uses the OSD size in
> TB.
>
> Christian
>
>> I resist doing anything for now in the hopes that someone has
>> something coherent to say (Christian? ;-)
>>
>> Thanks JR
>>
>>
>> On 9/8/2014 10:37 PM, JR wrote:
>>> Hi Christian,
>>>
>>> Ha ...
>>>
>>> root@osd45:~# ceph osd pool get rbd pg_num pg_num: 128
>>> root@osd45:~# ceph osd pool get rbd pgp_num pgp_num: 64
>>>
>>> That's the explanation! I did run the command but it spit out
>>> some (what I thought was a harmless) warning; should have
>>> checked more carefully.
>>>
>>> I now have the expected data movement.
>>>
>>> Thanks alot! JR
>>>
>>> On 9/8/2014 10:04 PM, Christian Balzer wrote:
>>>>
>>>> Hello,
>>>>
>>>> On Mon, 08 Sep 2014 18:30:07 -0400 JR wrote:
>>>>
>>>>> Hi Christian, all,
>>>>>
>>>>> Having researched this a bit more, it seemed that just
>>>>> doing
>>>>>
>>>>> ceph osd pool set rbd pg_num 128 ceph osd pool set rbd
>>>>> pgp_num 128
>>>>>
>>>>> might be the answer. Alas, it was not. After running the
>>>>> above the cluster just sat there.
>>>>>
>>>> Really now? No data movement, no health warnings during that
>>>> in the logs, no other error in the logs or when issuing that
>>>> command? Is it really at 128 now, verified with "ceph osd
>>>> pool get rbd pg_num"?
>>>>
>>>> You really want to get this addressed as per the previous
>>>> reply before doing anything further. Because with just 64
>>>> PGs (as in only 8 per OSD!) massive imbalances are a given.
>>>>
>>>>> Finally, reading some more, I ran:
>>>>>
>>>>> ceph osd reweight-by-utilization
>>>>>
>>>> Reading can be dangerous. ^o^
>>>>
>>>> I didn't mention this, as it never worked for me in any
>>>> predictable way and with a desirable outcome, especially in
>>>> situations like yours.
>>>>
>>>>> This accomplished moving the utilization of the first
>>>>> drive on the affected node to the 2nd drive! .e.g.:
>>>>>
>>>>> ------- BEFORE RUNNING: ------- Filesystem Use%
>>>>> /dev/sdc1 57% /dev/sdb1 65% Filesystem Use%
>>>>> /dev/sdc1 90% /dev/sdb1 75% Filesystem Use%
>>>>> /dev/sdb1 52% /dev/sdc1 52% Filesystem Use%
>>>>> /dev/sdc1 54% /dev/sdb1 63%
>>>>>
>>>>> ------- AFTER RUNNING: ------- Filesystem Use%
>>>>> /dev/sdc1 57% /dev/sdb1 65% Filesystem Use%
>>>>> /dev/sdc1 70% ** these two swapped (roughly)
>>>>> ** /dev/sdb1 92% ** ^^^^^ ^^^ ^^^^^^^ **
>>>>> Filesystem Use% /dev/sdb1 52% /dev/sdc1 52%
>>>>> Filesystem Use% /dev/sdc1 54% /dev/sdb1 63%
>>>>>
>>>>> root@osd45:~# ceph osd tree # id weight type name
>>>>> up/down reweight -1 3.44 root default -2 0.86
>>>>> host osd45 0 0.43 osd.0 up 1 4
>>>>> 0.43 osd.4 up 1 -3 0.86
>>>>> host osd42 1 0.43 osd.1 up 1 5 0.43
>>>>> osd.5 up 1 -4 0.86 host osd44 2
>>>>> 0.43 osd.2 up 1 6 0.43
>>>>> osd.6 up 1 -5 0.86 host osd43 3
>>>>> 0.43 osd.3 up 1 7 0.43
>>>>> osd.7 up 0.7007
>>>>>
>>>>> So this isn't the answer either.
>>>>>
>>>> It might have been, if it had more PGs to distribute things
>>>> along, see above. But even then with the default dumpling
>>>> tunables it might not be much better.
>>>>
>>>>> Could someone please chime in with an
>>>>> explanation/suggestion?
>>>>>
>>>>> I suspect that might make sense to use 'ceph osd reweight
>>>>> osd.7 1' and then run some form of 'ceph osd crush ...'?
>>>>>
>>>> No need to crush anything, reweight it to 1 after adding
>>>> PGs/PGPs and after all that data movement has finished
>>>> slowly dial down any still overly utilized OSD.
>>>>
>>>> Also per the "Uneven OSD usage" thread, you might run into a
>>>> "full" situation during data re-distribution. Increase PGs
>>>> in small (64) increments.
>>>>
>>>>> Of course, I've read a number of things which suggest that
>>>>> the two things I've done should have fixed my problem.
>>>>>
>>>>> Is it (gasp!) possible that this, as Christian suggests,
>>>>> is a dumpling issue and, were I running on firefly, it
>>>>> would be sufficient?
>>>>>
>>>> Running Firefly with all the tunables and probably
>>>> hashpspool. Most of the tunables with the exception of
>>>> "chooseleaf_vary_r" are available on dumpling, hashpspool
>>>> isn't AFAIK. See
>>>> http://ceph.com/docs/master/rados/operations/crush-map/#tunables
>>>>
>>>>
>>>>
>>>>
Christian
>>>>>
>>>>> Thanks much JR On 9/8/2014 1:50 PM, JR wrote:
>>>>>> Hi Christian,
>>>>>>
>>>>>> I have 448 PGs and 448 PGPs (according to ceph -s).
>>>>>>
>>>>>> This seems borne out by:
>>>>>>
>>>>>> root@osd45:~# rados lspools data metadata rbd volumes
>>>>>> images root@osd45:~# for i in $(rados lspools); do echo
>>>>>> "$i pg($(ceph osd pool get $i pg_num), pgp$(ceph osd
>>>>>> pool get $i pg_num)"; done data pg(pg_num: 64, pgppg_num:
>>>>>> 64 metadata pg(pg_num: 64, pgppg_num: 64 rbd pg(pg_num:
>>>>>> 64, pgppg_num: 64 volumes pg(pg_num: 128, pgppg_num: 128
>>>>>> images pg(pg_num: 128, pgppg_num: 128
>>>>>>
>>>>>> According to the formula discussed in 'Uneven OSD
>>>>>> usage,'
>>>>>>
>>>>>> "The formula is actually OSDs * 100 / replication
>>>>>>
>>>>>> in my case:
>>>>>>
>>>>>> 8*100/2=400
>>>>>>
>>>>>> So I'm erroring on the large size?
>>>>>>
>>>>>> Or, does this formula apply on by pool basis? Of my 5
>>>>>> pools I'm using 3:
>>>>>>
>>>>>> root@osd45:~# rados df|cut -c1-45 pool name category
>>>>>> KB data - 0 images -
>>>>>> 0 metadata - 10 rbd
>>>>>> - 568489533 volumes - 594078601
>>>>>> total used 2326235048 285923 total avail
>>>>>> 1380814968 total space 3707050016
>>>>>>
>>>>>> So should I up the number of PGs for the rbd and volumes
>>>>>> pools?
>>>>>>
>>>>>> I'll continue looking at docs, but for now I'll send
>>>>>> this off.
>>>>>>
>>>>>> Thanks very much, Christain.
>>>>>>
>>>>>> ps. This cluster is self-contained and all nodes in it
>>>>>> are completely loaded (i.e., I can't add any more nodes
>>>>>> nor disks). It's also not an option at the moment to
>>>>>> upgrade to firefly (can't make a big change before
>>>>>> sending it out the door).
>>>>>>
>>>>>>
>>>>>>
>>>>>> On 9/8/2014 12:09 PM, Christian Balzer wrote:
>>>>>>>
>>>>>>> Hello,
>>>>>>>
>>>>>>> On Mon, 08 Sep 2014 11:42:59 -0400 JR wrote:
>>>>>>>
>>>>>>>> Greetings all,
>>>>>>>>
>>>>>>>> I have a small ceph cluster (4 nodes, 2 osds per
>>>>>>>> node) which recently started showing:
>>>>>>>>
>>>>>>>> root@ocd45:~# ceph health HEALTH_WARN 1 near full
>>>>>>>> osd(s)
>>>>>>>>
>>>>>>>> admin@node4:~$ for i in 2 3 4 5; do sudo ssh osd4$i
>>>>>>>> df -h |egrep 'Filesystem|osd/ceph'; done Filesystem
>>>>>>>> Size Used Avail Use% Mounted on /dev/sdc1
>>>>>>>> 442G 249G 194G 57% /var/lib/ceph/osd/ceph-5
>>>>>>>> /dev/sdb1 442G 287G 156G 65%
>>>>>>>> /var/lib/ceph/osd/ceph-1 Filesystem Size Used
>>>>>>>> Avail Use% Mounted on /dev/sdc1 442G 396G
>>>>>>>> 47G 90% /var/lib/ceph/osd/ceph-7 /dev/sdb1
>>>>>>>> 442G 316G 127G 72% /var/lib/ceph/osd/ceph-3
>>>>>>>> Filesystem Size Used Avail Use% Mounted on /dev/sdb1
>>>>>>>> 442G 229G 214G 52% /var/lib/ceph/osd/ceph-2
>>>>>>>> /dev/sdc1 442G 229G 214G 52%
>>>>>>>> /var/lib/ceph/osd/ceph-6 Filesystem Size Used
>>>>>>>> Avail Use% Mounted on /dev/sdc1 442G 238G
>>>>>>>> 205G 54% /var/lib/ceph/osd/ceph-4 /dev/sdb1
>>>>>>>> 442G 278G 165G 63% /var/lib/ceph/osd/ceph-0
>>>>>>>>
>>>>>>>>
>>>>>>> See the very recent "Uneven OSD usage" for a
>>>>>>> discussion about this. What are your PG/PGP values?
>>>>>>>
>>>>>>>> This cluster has been running for weeks, under
>>>>>>>> significant load, and has been 100% stable.
>>>>>>>> Unfortunately we have to ship it out of the building
>>>>>>>> to another part of our business (where we will have
>>>>>>>> little access to it).
>>>>>>>>
>>>>>>>> Based on what I've read about 'ceph osd reweight'
>>>>>>>> I'm a bit hesitant to just run it (I don't want to
>>>>>>>> do anything that impacts this cluster's stability).
>>>>>>>>
>>>>>>>> Is there another, better way to equalize the
>>>>>>>> distribution the data on the osd partitions?
>>>>>>>>
>>>>>>>> I'm running dumpling.
>>>>>>>>
>>>>>>> As per the thread and my experience, Firefly would
>>>>>>> solve this. If you can upgrade during a weekend or
>>>>>>> whenever there is little to no access, do it.
>>>>>>>
>>>>>>> Another option (of course any and all of these will
>>>>>>> result in data movement, so pick an appropriate time),
>>>>>>> would be to "use ceph osd reweight" to lower the
>>>>>>> weight of osd.7 in particular.
>>>>>>>
>>>>>>> Lastly, given the utilization of your cluster, your
>>>>>>> really ought to deploy more OSDs and/or more nodes, if
>>>>>>> a node would go down you'd easily get into a "real"
>>>>>>> near full or full situation.
>>>>>>>
>>>>>>> Regards,
>>>>>>>
>>>>>>> Christian
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>>
>>>
>>
>
>
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