[ceph-users] Ceph cache pool full

David Turner drakonstein at gmail.com
Fri Oct 6 10:07:58 PDT 2017


All of this data is test data, yeah?  I would start by removing the
cache-tier and pool, recreate it and attach it, configure all of the
settings including the maximums, and start testing things again.  I would
avoid doing the 1.3TB file test until after you've confirmed that the
smaller files are being flushed appropriately to the data pool (manually
flushing/evicting it) and then scale up your testing to the larger files.
On Fri, Oct 6, 2017 at 12:54 PM Shawfeng Dong <shaw at ucsc.edu> wrote:

> Curiously, it has been quite a while, but there is still no object in the
> underlying data pool:
> # rados -p cephfs_data ls
>
> Any advice?
>
> On Fri, Oct 6, 2017 at 9:45 AM, David Turner <drakonstein at gmail.com>
> wrote:
>
>> Notice in the URL for the documentation the use of "luminous".  When you
>> looked a few weeks ago, you might have been looking at the documentation
>> for a different version of Ceph.  You can change that to jewel, hammer,
>> kraken, master, etc depending on which version of Ceph you are running or
>> reading about.  Google gets confused and will pull up random versions of
>> the ceph documentation for a page. It's on us to make sure that the url is
>> pointing to the version of Ceph that we are using.
>>
>> While it's sitting there in the flush command, can you see if there are
>> any objects in the underlying data pool?  Hopefully the count will be
>> growing.
>>
>> On Fri, Oct 6, 2017 at 12:39 PM Shawfeng Dong <shaw at ucsc.edu> wrote:
>>
>>> Hi Christian,
>>>
>>> I set those via CLI:
>>> # ceph osd pool set cephfs_cache target_max_bytes 1099511627776
>>> # ceph osd pool set cephfs_cache target_max_objects 1000000
>>>
>>> but manual flushing doesn't appear to work:
>>> # rados -p cephfs_cache cache-flush-evict-all
>>>         1000000046a.00000ca6
>>>
>>> it just gets stuck there for a long time.
>>>
>>> Any suggestion? Do I need to restart the daemons or reboot the nodes?
>>>
>>> Thanks,
>>> Shaw
>>>
>>>
>>>
>>> On Fri, Oct 6, 2017 at 9:31 AM, Christian Balzer <chibi at gol.com> wrote:
>>>
>>>> On Fri, 6 Oct 2017 09:14:40 -0700 Shawfeng Dong wrote:
>>>>
>>>> > I found the command: rados -p cephfs_cache cache-flush-evict-all
>>>> >
>>>> That's not what you want/need.
>>>> Though it will fix your current "full" issue.
>>>>
>>>> > The documentation (
>>>> > http://docs.ceph.com/docs/luminous/rados/operations/cache-tiering/)
>>>> has
>>>> > been improved a lot since I last checked it a few weeks ago!
>>>> >
>>>> The need to set max_bytes and max_objects has been documented for ages
>>>> (since Hammer).
>>>>
>>>> more below...
>>>>
>>>> > -Shaw
>>>> >
>>>> > On Fri, Oct 6, 2017 at 9:10 AM, Shawfeng Dong <shaw at ucsc.edu> wrote:
>>>> >
>>>> > > Thanks, Luis.
>>>> > >
>>>> > > I've just set max_bytes and max_objects:
>>>> How?
>>>> Editing the conf file won't help until a restart.
>>>>
>>>> > > target_max_objects: 1000000 (1M)
>>>> > > target_max_bytes: 1099511627776 (1TB)
>>>> >
>>>> I'd lower that or the cache_target_full_ratio by another 10%.
>>>>
>>>> Christian
>>>> > >
>>>> > > but nothing appears to be happening. Is there a way to force
>>>> flushing?
>>>> > >
>>>> > > Thanks,
>>>> > > Shaw
>>>> > >
>>>> > > On Fri, Oct 6, 2017 at 8:55 AM, Luis Periquito <periquito at gmail.com
>>>> >
>>>> > > wrote:
>>>> > >
>>>> > >> Not looking at anything else, you didn't set the max_bytes or
>>>> > >> max_objects for it to start flushing...
>>>> > >>
>>>> > >> On Fri, Oct 6, 2017 at 4:49 PM, Shawfeng Dong <shaw at ucsc.edu>
>>>> wrote:
>>>> > >> > Dear all,
>>>> > >> >
>>>> > >> > Thanks a lot for the very insightful comments/suggestions!
>>>> > >> >
>>>> > >> > There are 3 OSD servers in our pilot Ceph cluster, each with 2x
>>>> 1TB SSDs
>>>> > >> > (boot disks), 12x 8TB SATA HDDs and 2x 1.2TB NVMe SSDs. We use
>>>> the
>>>> > >> bluestore
>>>> > >> > backend, with the first NVMe as the WAL and DB devices for OSDs
>>>> on the
>>>> > >> HDDs.
>>>> > >> > And we try to create a cache tier out of the second NVMes.
>>>> > >> >
>>>> > >> > Here are the outputs of the commands suggested by David:
>>>> > >> >
>>>> > >> > 1) # ceph df
>>>> > >> > GLOBAL:
>>>> > >> >     SIZE     AVAIL     RAW USED     %RAW USED
>>>> > >> >     265T      262T        2847G          1.05
>>>> > >> > POOLS:
>>>> > >> >     NAME                ID     USED      %USED      MAX AVAIL
>>>> > >>  OBJECTS
>>>> > >> >     cephfs_data         1          0          0          248T
>>>> > >>  0
>>>> > >> >     cephfs_metadata     2      8515k          0          248T
>>>> > >> 24
>>>> > >> >     cephfs_cache        3      1381G     100.00             0
>>>> > >> 355385
>>>> > >> >
>>>> > >> > 2) # ceph osd df
>>>> > >> >  0   hdd 7.27829  1.00000 7452G 2076M  7450G  0.03  0.03 174
>>>> > >> >  1   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 169
>>>> > >> >  2   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 173
>>>> > >> >  3   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 159
>>>> > >> >  4   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 173
>>>> > >> >  5   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 162
>>>> > >> >  6   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 149
>>>> > >> >  7   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 179
>>>> > >> >  8   hdd 7.27829  1.00000 7452G 2076M  7450G  0.03  0.03 163
>>>> > >> >  9   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 194
>>>> > >> > 10   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 185
>>>> > >> > 11   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 168
>>>> > >> > 36  nvme 1.09149  1.00000 1117G  855G   262G 76.53 73.01  79
>>>> > >> > 12   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 180
>>>> > >> > 13   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 168
>>>> > >> > 14   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 178
>>>> > >> > 15   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 170
>>>> > >> > 16   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 149
>>>> > >> > 17   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 203
>>>> > >> > 18   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 173
>>>> > >> > 19   hdd 7.27829  1.00000 7452G 2076M  7450G  0.03  0.03 158
>>>> > >> > 20   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 154
>>>> > >> > 21   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 160
>>>> > >> > 22   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 167
>>>> > >> > 23   hdd 7.27829  1.00000 7452G 2076M  7450G  0.03  0.03 188
>>>> > >> > 37  nvme 1.09149  1.00000 1117G 1061G 57214M 95.00 90.63  98
>>>> > >> > 24   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 187
>>>> > >> > 25   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 200
>>>> > >> > 26   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 147
>>>> > >> > 27   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 171
>>>> > >> > 28   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 162
>>>> > >> > 29   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 152
>>>> > >> > 30   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 174
>>>> > >> > 31   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 176
>>>> > >> > 32   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 182
>>>> > >> > 33   hdd 7.27829  1.00000 7452G 2072M  7450G  0.03  0.03 155
>>>> > >> > 34   hdd 7.27829  1.00000 7452G 2076M  7450G  0.03  0.03 166
>>>> > >> > 35   hdd 7.27829  1.00000 7452G 2076M  7450G  0.03  0.03 176
>>>> > >> > 38  nvme 1.09149  1.00000 1117G  857G   260G 76.71 73.18  79
>>>> > >> >                     TOTAL  265T 2847G   262T  1.05
>>>> > >> > MIN/MAX VAR: 0.03/90.63  STDDEV: 22.81
>>>> > >> >
>>>> > >> > 3) # ceph osd tree
>>>> > >> > -1       265.29291 root default
>>>> > >> > -3        88.43097     host pulpo-osd01
>>>> > >> >  0   hdd   7.27829         osd.0            up  1.00000 1.00000
>>>> > >> >  1   hdd   7.27829         osd.1            up  1.00000 1.00000
>>>> > >> >  2   hdd   7.27829         osd.2            up  1.00000 1.00000
>>>> > >> >  3   hdd   7.27829         osd.3            up  1.00000 1.00000
>>>> > >> >  4   hdd   7.27829         osd.4            up  1.00000 1.00000
>>>> > >> >  5   hdd   7.27829         osd.5            up  1.00000 1.00000
>>>> > >> >  6   hdd   7.27829         osd.6            up  1.00000 1.00000
>>>> > >> >  7   hdd   7.27829         osd.7            up  1.00000 1.00000
>>>> > >> >  8   hdd   7.27829         osd.8            up  1.00000 1.00000
>>>> > >> >  9   hdd   7.27829         osd.9            up  1.00000 1.00000
>>>> > >> > 10   hdd   7.27829         osd.10           up  1.00000 1.00000
>>>> > >> > 11   hdd   7.27829         osd.11           up  1.00000 1.00000
>>>> > >> > 36  nvme   1.09149         osd.36           up  1.00000 1.00000
>>>> > >> > -5        88.43097     host pulpo-osd02
>>>> > >> > 12   hdd   7.27829         osd.12           up  1.00000 1.00000
>>>> > >> > 13   hdd   7.27829         osd.13           up  1.00000 1.00000
>>>> > >> > 14   hdd   7.27829         osd.14           up  1.00000 1.00000
>>>> > >> > 15   hdd   7.27829         osd.15           up  1.00000 1.00000
>>>> > >> > 16   hdd   7.27829         osd.16           up  1.00000 1.00000
>>>> > >> > 17   hdd   7.27829         osd.17           up  1.00000 1.00000
>>>> > >> > 18   hdd   7.27829         osd.18           up  1.00000 1.00000
>>>> > >> > 19   hdd   7.27829         osd.19           up  1.00000 1.00000
>>>> > >> > 20   hdd   7.27829         osd.20           up  1.00000 1.00000
>>>> > >> > 21   hdd   7.27829         osd.21           up  1.00000 1.00000
>>>> > >> > 22   hdd   7.27829         osd.22           up  1.00000 1.00000
>>>> > >> > 23   hdd   7.27829         osd.23           up  1.00000 1.00000
>>>> > >> > 37  nvme   1.09149         osd.37           up  1.00000 1.00000
>>>> > >> > 36  nvme   1.09149         osd.36           up  1.00000 1.00000
>>>> > >> > -5        88.43097     host pulpo-osd02
>>>> > >> > 12   hdd   7.27829         osd.12           up  1.00000 1.00000
>>>> > >> > 13   hdd   7.27829         osd.13           up  1.00000 1.00000
>>>> > >> > 14   hdd   7.27829         osd.14           up  1.00000 1.00000
>>>> > >> > 15   hdd   7.27829         osd.15           up  1.00000 1.00000
>>>> > >> > 16   hdd   7.27829         osd.16           up  1.00000 1.00000
>>>> > >> > 17   hdd   7.27829         osd.17           up  1.00000 1.00000
>>>> > >> > 18   hdd   7.27829         osd.18           up  1.00000 1.00000
>>>> > >> > 19   hdd   7.27829         osd.19           up  1.00000 1.00000
>>>> > >> > 20   hdd   7.27829         osd.20           up  1.00000 1.00000
>>>> > >> > 21   hdd   7.27829         osd.21           up  1.00000 1.00000
>>>> > >> > 22   hdd   7.27829         osd.22           up  1.00000 1.00000
>>>> > >> > 23   hdd   7.27829         osd.23           up  1.00000 1.00000
>>>> > >> > 37  nvme   1.09149         osd.37           up  1.00000 1.00000
>>>> > >> > -7        88.43097     host pulpo-osd03
>>>> > >> > 24   hdd   7.27829         osd.24           up  1.00000 1.00000
>>>> > >> > 25   hdd   7.27829         osd.25           up  1.00000 1.00000
>>>> > >> > 26   hdd   7.27829         osd.26           up  1.00000 1.00000
>>>> > >> > 27   hdd   7.27829         osd.27           up  1.00000 1.00000
>>>> > >> > 28   hdd   7.27829         osd.28           up  1.00000 1.00000
>>>> > >> > 29   hdd   7.27829         osd.29           up  1.00000 1.00000
>>>> > >> > 30   hdd   7.27829         osd.30           up  1.00000 1.00000
>>>> > >> > 31   hdd   7.27829         osd.31           up  1.00000 1.00000
>>>> > >> > 32   hdd   7.27829         osd.32           up  1.00000 1.00000
>>>> > >> > 33   hdd   7.27829         osd.33           up  1.00000 1.00000
>>>> > >> > 34   hdd   7.27829         osd.34           up  1.00000 1.00000
>>>> > >> > 35   hdd   7.27829         osd.35           up  1.00000 1.00000
>>>> > >> > 38  nvme   1.09149         osd.38           up  1.00000 1.00000
>>>> > >> >
>>>> > >> > 4) # ceph osd pool get cephfs_cache all
>>>> > >> > min_size: 2
>>>> > >> > crash_replay_interval: 0
>>>> > >> > pg_num: 128
>>>> > >> > pgp_num: 128
>>>> > >> > crush_rule: pulpo_nvme
>>>> > >> > hashpspool: true
>>>> > >> > nodelete: false
>>>> > >> > nopgchange: false
>>>> > >> > nosizechange: false
>>>> > >> > write_fadvise_dontneed: false
>>>> > >> > noscrub: false
>>>> > >> > nodeep-scrub: false
>>>> > >> > hit_set_type: bloom
>>>> > >> > hit_set_period: 14400
>>>> > >> > hit_set_count: 12
>>>> > >> > hit_set_fpp: 0.05
>>>> > >> > use_gmt_hitset: 1
>>>> > >> > auid: 0
>>>> > >> > target_max_objects: 0
>>>> > >> > target_max_bytes: 0
>>>> > >> > cache_target_dirty_ratio: 0.4
>>>> > >> > cache_target_dirty_high_ratio: 0.6
>>>> > >> > cache_target_full_ratio: 0.8
>>>> > >> > cache_min_flush_age: 0
>>>> > >> > cache_min_evict_age: 0
>>>> > >> > min_read_recency_for_promote: 0
>>>> > >> > min_write_recency_for_promote: 0
>>>> > >> > fast_read: 0
>>>> > >> > hit_set_grade_decay_rate: 0
>>>> > >> > crash_replay_interval: 0
>>>> > >> >
>>>> > >> > Do you see anything wrong? We had written some small files to
>>>> the CephFS
>>>> > >> > before we tried to write the big 1TB file. What is puzzling to
>>>> me is
>>>> > >> that no
>>>> > >> > data has been written back to the data pool.
>>>> > >> >
>>>> > >> > Best,
>>>> > >> > Shaw
>>>> > >> >
>>>> > >> > On Fri, Oct 6, 2017 at 6:46 AM, David Turner <
>>>> drakonstein at gmail.com>
>>>> > >> wrote:
>>>> > >> >>
>>>> > >> >>
>>>> > >> >>
>>>> > >> >> On Fri, Oct 6, 2017, 1:05 AM Christian Balzer <chibi at gol.com>
>>>> wrote:
>>>> > >> >>>
>>>> > >> >>>
>>>> > >> >>> Hello,
>>>> > >> >>>
>>>> > >> >>> On Fri, 06 Oct 2017 03:30:41 +0000 David Turner wrote:
>>>> > >> >>>
>>>> > >> >>> > You're missing most all of the important bits. What the osds
>>>> in your
>>>> > >> >>> > cluster look like, your tree, and your cache pool settings.
>>>> > >> >>> >
>>>> > >> >>> > ceph df
>>>> > >> >>> > ceph osd df
>>>> > >> >>> > ceph osd tree
>>>> > >> >>> > ceph osd pool get cephfs_cache all
>>>> > >> >>> >
>>>> > >> >>> Especially the last one.
>>>> > >> >>>
>>>> > >> >>> My money is on not having set target_max_objects and
>>>> target_max_bytes
>>>> > >> to
>>>> > >> >>> sensible values along with the ratios.
>>>> > >> >>> In short, not having read the (albeit spotty) documentation.
>>>> > >> >>>
>>>> > >> >>> > You have your writeback cache on 3 nvme drives. It looks
>>>> like you
>>>> > >> have
>>>> > >> >>> > 1.6TB available between them for the cache. I don't know the
>>>> > >> behavior
>>>> > >> >>> > of a
>>>> > >> >>> > writeback cache tier on cephfs for large files, but I would
>>>> guess
>>>> > >> that
>>>> > >> >>> > it
>>>> > >> >>> > can only hold full files and not flush partial files.
>>>> > >> >>>
>>>> > >> >>> I VERY much doubt that, if so it would be a massive flaw.
>>>> > >> >>> One assumes that cache operations work on the RADOS object
>>>> level, no
>>>> > >> >>> matter what.
>>>> > >> >>
>>>> > >> >> I hope that it is on the rados level, but not a single object
>>>> had been
>>>> > >> >> flushed to the backing pool. So I hazarded a guess. Seeing his
>>>> > >> settings will
>>>> > >> >> shed more light.
>>>> > >> >>>
>>>> > >> >>>
>>>> > >> >>> > That would mean your
>>>> > >> >>> > cache needs to have enough space for any file being written
>>>> to the
>>>> > >> >>> > cluster.
>>>> > >> >>> > In this case a 1.3TB file with 3x replication would require
>>>> 3.9TB
>>>> > >> (more
>>>> > >> >>> > than double what you have available) of available space in
>>>> your
>>>> > >> >>> > writeback
>>>> > >> >>> > cache.
>>>> > >> >>> >
>>>> > >> >>> > There are very few use cases that benefit from a cache tier.
>>>> The
>>>> > >> docs
>>>> > >> >>> > for
>>>> > >> >>> > Luminous warn as much.
>>>> > >> >>> You keep repeating that like a broken record.
>>>> > >> >>>
>>>> > >> >>> And while certainly not false I for one wouldn't be able to use
>>>> > >> (justify
>>>> > >> >>> using) Ceph w/o cache tiers in our main use case.
>>>> > >> >>>
>>>> > >> >>>
>>>> > >> >>> In this case I assume they were following and old cheat sheet
>>>> or such,
>>>> > >> >>> suggesting the previously required cache tier with EC pools.
>>>> > >> >>
>>>> > >> >>
>>>> > >> >>
>>>> http://docs.ceph.com/docs/luminous/rados/operations/cache-tiering/
>>>> > >> >>
>>>> > >> >> I know I keep repeating it, especially recently as there have
>>>> been a
>>>> > >> lot
>>>> > >> >> of people asking about it. The Luminous docs added a large
>>>> section
>>>> > >> about how
>>>> > >> >> it is probably not what you want. Like me, it is not saying
>>>> that there
>>>> > >> are
>>>> > >> >> no use cases for it. There was no information provided about
>>>> the use
>>>> > >> case
>>>> > >> >> and I made some suggestions/guesses. I'm also guessing that
>>>> they are
>>>> > >> >> following a guide where a writeback cache was necessary for
>>>> CephFS to
>>>> > >> use EC
>>>> > >> >> prior to Luminous. I also usually add that people should test
>>>> it out
>>>> > >> and
>>>> > >> >> find what works best for them. I will always defer to your
>>>> practical
>>>> > >> use of
>>>> > >> >> cache tiers as well, especially when using rbds.
>>>> > >> >>
>>>> > >> >> I manage a cluster that I intend to continue running a
>>>> writeback cache
>>>> > >> in
>>>> > >> >> front of CephFS on the same drives as the EC pool. The use case
>>>> > >> receives a
>>>> > >> >> good enough benefit from the cache tier that it isn't even
>>>> required to
>>>> > >> use
>>>> > >> >> flash media to see it. It is used for video editing and the
>>>> files are
>>>> > >> >> usually modified and read within the first 24 hours and then
>>>> left in
>>>> > >> cold
>>>> > >> >> storage until deleted. I have the cache timed to keep
>>>> everything in it
>>>> > >> for
>>>> > >> >> 24 hours and then evict it by using a minimum time to flush and
>>>> evict
>>>> > >> at 24
>>>> > >> >> hours and a target max bytes of 0. All files are in there for
>>>> that
>>>> > >> time and
>>>> > >> >> then it never has to decide what to keep as it doesn't keep
>>>> anything
>>>> > >> longer
>>>> > >> >> than that. Luckily read performance from cold storage is not a
>>>> > >> requirement
>>>> > >> >> of this cluster as any read operation has to first read it from
>>>> EC
>>>> > >> storage,
>>>> > >> >> write it to replica storage, and then read it from replica
>>>> storage...
>>>> > >> Yuck.
>>>> > >> >>>
>>>> > >> >>>
>>>> > >> >>> Christian
>>>> > >> >>>
>>>> > >> >>> >What is your goal by implementing this cache? If the
>>>> > >> >>> > answer is to utilize extra space on the nvmes, then just
>>>> remove it
>>>> > >> and
>>>> > >> >>> > say
>>>> > >> >>> > thank you. The better use of nvmes in that case are as a
>>>> part of the
>>>> > >> >>> > bluestore stack and give your osds larger DB partitions.
>>>> Keeping
>>>> > >> your
>>>> > >> >>> > metadata pool on nvmes is still a good idea.
>>>> > >> >>> >
>>>> > >> >>> > On Thu, Oct 5, 2017, 7:45 PM Shawfeng Dong <shaw at ucsc.edu>
>>>> wrote:
>>>> > >> >>> >
>>>> > >> >>> > > Dear all,
>>>> > >> >>> > >
>>>> > >> >>> > > We just set up a Ceph cluster, running the latest stable
>>>> release
>>>> > >> Ceph
>>>> > >> >>> > > v12.2.0 (Luminous):
>>>> > >> >>> > > # ceph --version
>>>> > >> >>> > > ceph version 12.2.0
>>>> (32ce2a3ae5239ee33d6150705cdb24d43bab910c)
>>>> > >> >>> > > luminous
>>>> > >> >>> > > (rc)
>>>> > >> >>> > >
>>>> > >> >>> > > The goal is to serve Ceph filesystem, for which we created
>>>> 3
>>>> > >> pools:
>>>> > >> >>> > > # ceph osd lspools
>>>> > >> >>> > > 1 cephfs_data,2 cephfs_metadata,3 cephfs_cache,
>>>> > >> >>> > > where
>>>> > >> >>> > > * cephfs_data is the data pool (36 OSDs on HDDs), which is
>>>> > >> >>> > > erased-coded;
>>>> > >> >>> > > * cephfs_metadata is the metadata pool
>>>> > >> >>> > > * cephfs_cache is the cache tier (3 OSDs on NVMes) for
>>>> > >> cephfs_data.
>>>> > >> >>> > > The
>>>> > >> >>> > > cache-mode is writeback.
>>>> > >> >>> > >
>>>> > >> >>> > > Everything had worked fine, until today when we tried to
>>>> copy a
>>>> > >> 1.3TB
>>>> > >> >>> > > file
>>>> > >> >>> > > to the CephFS.  We got the "No space left on device" error!
>>>> > >> >>> > >
>>>> > >> >>> > > 'ceph -s' says some OSDs are full:
>>>> > >> >>> > > # ceph -s
>>>> > >> >>> > >   cluster:
>>>> > >> >>> > >     id:     e18516bf-39cb-4670-9f13-88ccb7d19769
>>>> > >> >>> > >     health: HEALTH_ERR
>>>> > >> >>> > >             full flag(s) set
>>>> > >> >>> > >             1 full osd(s)
>>>> > >> >>> > >             1 pools have many more objects per pg than
>>>> average
>>>> > >> >>> > >
>>>> > >> >>> > >   services:
>>>> > >> >>> > >     mon: 3 daemons, quorum
>>>> pulpo-admin,pulpo-mon01,pulpo-mds01
>>>> > >> >>> > >     mgr: pulpo-mds01(active), standbys: pulpo-admin,
>>>> pulpo-mon01
>>>> > >> >>> > >     mds: pulpos-1/1/1 up  {0=pulpo-mds01=up:active}
>>>> > >> >>> > >     osd: 39 osds: 39 up, 39 in
>>>> > >> >>> > >          flags full
>>>> > >> >>> > >
>>>> > >> >>> > >   data:
>>>> > >> >>> > >     pools:   3 pools, 2176 pgs
>>>> > >> >>> > >     objects: 347k objects, 1381 GB
>>>> > >> >>> > >     usage:   2847 GB used, 262 TB / 265 TB avail
>>>> > >> >>> > >     pgs:     2176 active+clean
>>>> > >> >>> > >
>>>> > >> >>> > >   io:
>>>> > >> >>> > >     client:   19301 kB/s rd, 2935 op/s rd, 0 op/s wr
>>>> > >> >>> > >
>>>> > >> >>> > > And indeed the cache pool is full:
>>>> > >> >>> > > # rados df
>>>> > >> >>> > > POOL_NAME       USED  OBJECTS CLONES COPIES
>>>> MISSING_ON_PRIMARY
>>>> > >> >>> > > UNFOUND
>>>> > >> >>> > > DEGRADED RD_OPS   RD
>>>> > >> >>> > >     WR_OPS  WR
>>>> > >> >>> > > cephfs_cache    1381G  355385      0 710770
>>>>   0
>>>> > >> >>> > > 0
>>>> > >> >>> > >     0 10004954 15
>>>> > >> >>> > > 22G 1398063  1611G
>>>> > >> >>> > > cephfs_data         0       0      0      0
>>>>   0
>>>> > >> >>> > > 0
>>>> > >> >>> > >     0        0
>>>> > >> >>> > >   0       0      0
>>>> > >> >>> > > cephfs_metadata 8515k      24      0     72
>>>>   0
>>>> > >> >>> > > 0
>>>> > >> >>> > >     0        3  3
>>>> > >> >>> > > 072    3953 10541k
>>>> > >> >>> > >
>>>> > >> >>> > > total_objects    355409
>>>> > >> >>> > > total_used       2847G
>>>> > >> >>> > > total_avail      262T
>>>> > >> >>> > > total_space      265T
>>>> > >> >>> > >
>>>> > >> >>> > > However, the data pool is completely empty! So it seems
>>>> that data
>>>> > >> has
>>>> > >> >>> > > only
>>>> > >> >>> > > been written to the cache pool, but not written back to
>>>> the data
>>>> > >> >>> > > pool.
>>>> > >> >>> > >
>>>> > >> >>> > > I am really at a loss whether this is due to a setup error
>>>> on my
>>>> > >> >>> > > part, or
>>>> > >> >>> > > a Luminous bug. Could anyone shed some light on this?
>>>> Please let
>>>> > >> me
>>>> > >> >>> > > know if
>>>> > >> >>> > > you need any further info.
>>>> > >> >>> > >
>>>> > >> >>> > > Best,
>>>> > >> >>> > > Shaw
>>>> > >> >>> > > _______________________________________________
>>>> > >> >>> > > ceph-users mailing list
>>>> > >> >>> > > ceph-users at lists.ceph.com
>>>> > >> >>> > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
>>>> > >> >>> > >
>>>> > >> >>>
>>>> > >> >>>
>>>> > >> >>> --
>>>> > >> >>> Christian Balzer        Network/Systems Engineer
>>>> > >> >>> chibi at gol.com           Rakuten Communications
>>>> > >> >>> _______________________________________________
>>>> > >> >>> ceph-users mailing list
>>>> > >> >>> ceph-users at lists.ceph.com
>>>> > >> >>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
>>>> > >> >>
>>>> > >> >>
>>>> > >> >> _______________________________________________
>>>> > >> >> ceph-users mailing list
>>>> > >> >> ceph-users at lists.ceph.com
>>>> > >> >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
>>>> > >> >>
>>>> > >> >
>>>> > >> >
>>>> > >> > _______________________________________________
>>>> > >> > ceph-users mailing list
>>>> > >> > ceph-users at lists.ceph.com
>>>> > >> > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
>>>> > >> >
>>>> > >>
>>>> > >
>>>> > >
>>>>
>>>>
>>>> --
>>>> Christian Balzer        Network/Systems Engineer
>>>> chibi at gol.com           Rakuten Communications
>>>>
>>>
>>> _______________________________________________
>>> ceph-users mailing list
>>> ceph-users at lists.ceph.com
>>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
>>>
>>
>
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