I found the command: rados -p cephfs_cache cache-flush-evict-all 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!
-Shaw On Fri, Oct 6, 2017 at 9:10 AM, Shawfeng Dong <s...@ucsc.edu> wrote: > Thanks, Luis. > > I've just set max_bytes and max_objects: > target_max_objects: 1000000 (1M) > target_max_bytes: 1099511627776 (1TB) > > 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 <periqu...@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 <s...@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 <drakonst...@gmail.com> >> wrote: >> >> >> >> >> >> >> >> On Fri, Oct 6, 2017, 1:05 AM Christian Balzer <ch...@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 <s...@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@lists.ceph.com >> >>> > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >> >>> > > >> >>> >> >>> >> >>> -- >> >>> Christian Balzer Network/Systems Engineer >> >>> ch...@gol.com Rakuten Communications >> >>> _______________________________________________ >> >>> ceph-users mailing list >> >>> ceph-users@lists.ceph.com >> >>> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >> >> >> >> >> >> _______________________________________________ >> >> ceph-users mailing list >> >> ceph-users@lists.ceph.com >> >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >> >> >> > >> > >> > _______________________________________________ >> > ceph-users mailing list >> > ceph-users@lists.ceph.com >> > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >> > >> > >
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