On Mon, Feb 26, 2018 at 9:12 AM Reed Dier <reed.d...@focusvq.com> wrote:
> After my last round of backfills completed, I started 5 more bluestore > conversions, which helped me recognize a very specific pattern of > performance. > > pool objects-ssd id 20 > recovery io 757 MB/s, 10845 objects/s > > pool fs-metadata-ssd id 16 > recovery io 0 B/s, 36265 keys/s, 1633 objects/s > client io 2544 kB/s rd, 36788 B/s wr, 1 op/s rd, 0 op/s wr > > > The “non-throttled” backfills are only coming from filestore SSD OSD’s. > When backfilling from bluestore SSD OSD’s, they appear to be throttled at > the aforementioned <20 ops per OSD. > Wait, is that the current state? What are you referencing when you talk about recovery ops per second? Also, what are the values for osd_recovery_sleep_hdd and osd_recovery_sleep_hybrid, and can you validate via "ceph osd metadata" that your BlueStore SSD OSDs are correctly reporting both themselves and their journals as non-rotational? -Greg > > This would corroborate why the first batch of SSD’s I migrated to > bluestore were all at “full” speed, as all of the OSD’s they were > backfilling from were filestore based, compared to increasingly bluestore > backfill targets, leading to increasingly long backfill times as I move > from one host to the next. > > Looking at the recovery settings, the recovery_sleep and > recovery_sleep_ssd values across bluestore or filestore OSDs are showing as > 0 values, which means no sleep/throttle if I am reading everything > correctly. > > sudo ceph daemon osd.73 config show | grep recovery > "osd_allow_recovery_below_min_size": "true", > "osd_debug_skip_full_check_in_recovery": "false", > "osd_force_recovery_pg_log_entries_factor": "1.300000", > "osd_min_recovery_priority": "0", > "osd_recovery_cost": "20971520", > "osd_recovery_delay_start": "0.000000", > "osd_recovery_forget_lost_objects": "false", > "osd_recovery_max_active": "35", > "osd_recovery_max_chunk": "8388608", > "osd_recovery_max_omap_entries_per_chunk": "64000", > "osd_recovery_max_single_start": "1", > "osd_recovery_op_priority": "3", > "osd_recovery_op_warn_multiple": "16", > "osd_recovery_priority": "5", > "osd_recovery_retry_interval": "30.000000", > * "osd_recovery_sleep": "0.000000",* > "osd_recovery_sleep_hdd": "0.100000", > "osd_recovery_sleep_hybrid": "0.025000", > * "osd_recovery_sleep_ssd": "0.000000",* > "osd_recovery_thread_suicide_timeout": "300", > "osd_recovery_thread_timeout": "30", > "osd_scrub_during_recovery": "false", > > > As far as I know, the device class is configured correctly as far as I > know, it all shows as ssd/hdd correctly in ceph osd tree. > > So hopefully this may be enough of a smoking gun to help narrow down where > this may be stemming from. > > Thanks, > > Reed > > On Feb 23, 2018, at 10:04 AM, David Turner <drakonst...@gmail.com> wrote: > > Here is a [1] link to a ML thread tracking some slow backfilling on > bluestore. It came down to the backfill sleep setting for them. Maybe it > will help. > > [1] https://www.mail-archive.com/ceph-users@lists.ceph.com/msg40256.html > > On Fri, Feb 23, 2018 at 10:46 AM Reed Dier <reed.d...@focusvq.com> wrote: > >> Probably unrelated, but I do keep seeing this odd negative objects >> degraded message on the fs-metadata pool: >> >> pool fs-metadata-ssd id 16 >> -34/3 objects degraded (-1133.333%) >> recovery io 0 B/s, 89 keys/s, 2 objects/s >> client io 51289 B/s rd, 101 kB/s wr, 0 op/s rd, 0 op/s wr >> >> >> Don’t mean to clutter the ML/thread, however it did seem odd, maybe its a >> culprit? Maybe its some weird sampling interval issue thats been solved in >> 12.2.3? >> >> Thanks, >> >> Reed >> >> >> On Feb 23, 2018, at 8:26 AM, Reed Dier <reed.d...@focusvq.com> wrote: >> >> Below is ceph -s >> >> cluster: >> id: {id} >> health: HEALTH_WARN >> noout flag(s) set >> 260610/1068004947 objects misplaced (0.024%) >> Degraded data redundancy: 23157232/1068004947 objects >> degraded (2.168%), 332 pgs unclean, 328 pgs degraded, 328 pgs undersized >> >> services: >> mon: 3 daemons, quorum mon02,mon01,mon03 >> mgr: mon03(active), standbys: mon02 >> mds: cephfs-1/1/1 up {0=mon03=up:active}, 1 up:standby >> osd: 74 osds: 74 up, 74 in; 332 remapped pgs >> flags noout >> >> data: >> pools: 5 pools, 5316 pgs >> objects: 339M objects, 46627 GB >> usage: 154 TB used, 108 TB / 262 TB avail >> pgs: 23157232/1068004947 objects degraded (2.168%) >> 260610/1068004947 objects misplaced (0.024%) >> 4984 active+clean >> 183 active+undersized+degraded+remapped+backfilling >> 145 active+undersized+degraded+remapped+backfill_wait >> 3 active+remapped+backfill_wait >> 1 active+remapped+backfilling >> >> io: >> client: 8428 kB/s rd, 47905 B/s wr, 130 op/s rd, 0 op/s wr >> recovery: 37057 kB/s, 50 keys/s, 217 objects/s >> >> >> Also the two pools on the SSDs, are the objects pool at 4096 PG, and the >> fs-metadata pool at 32 PG. >> >> Are you sure the recovery is actually going slower, or are the individual >> ops larger or more expensive? >> >> The objects should not vary wildly in size. >> Even if they were differing in size, the SSDs are roughly idle in their >> current state of backfilling when examining wait in iotop, or atop, or >> sysstat/iostat. >> >> This compares to when I was fully saturating the SATA backplane with over >> 1000MB/s of writes to multiple disks when the backfills were going “full >> speed.” >> >> Here is a breakdown of recovery io by pool: >> >> pool objects-ssd id 20 >> recovery io 6779 kB/s, 92 objects/s >> client io 3071 kB/s rd, 50 op/s rd, 0 op/s wr >> >> pool fs-metadata-ssd id 16 >> recovery io 0 B/s, 28 keys/s, 2 objects/s >> client io 109 kB/s rd, 67455 B/s wr, 1 op/s rd, 0 op/s wr >> >> pool cephfs-hdd id 17 >> recovery io 40542 kB/s, 158 objects/s >> client io 10056 kB/s rd, 142 op/s rd, 0 op/s wr >> >> >> So the 24 HDD’s are outperforming the 50 SSD’s for recovery and client >> traffic at the moment, which seems conspicuous to me. >> >> Most of the OSD’s with recovery ops to the SSDs are reporting 8-12 ops, >> with one OSD occasionally spiking up to 300-500 for a few minutes. Stats >> being pulled by both local CollectD instances on each node, as well as the >> Influx plugin in MGR as we evaluate that against collectd. >> >> Thanks, >> >> Reed >> >> >> On Feb 22, 2018, at 6:21 PM, Gregory Farnum <gfar...@redhat.com> wrote: >> >> What's the output of "ceph -s" while this is happening? >> >> Is there some identifiable difference between these two states, like you >> get a lot of throughput on the data pools but then metadata recovery is >> slower? >> >> Are you sure the recovery is actually going slower, or are the individual >> ops larger or more expensive? >> >> My WAG is that recovering the metadata pool, composed mostly of >> directories stored in omap objects, is going much slower for some reason. >> You can adjust the cost of those individual ops some by >> changing osd_recovery_max_omap_entries_per_chunk (default: 8096), but I'm >> not sure which way you want to go or indeed if this has anything to do with >> the problem you're seeing. (eg, it could be that reading out the omaps is >> expensive, so you can get higher recovery op numbers by turning down the >> number of entries per request, but not actually see faster backfilling >> because you have to issue more requests.) >> -Greg >> >> On Wed, Feb 21, 2018 at 2:57 PM Reed Dier <reed.d...@focusvq.com> wrote: >> >>> Hi all, >>> >>> I am running into an odd situation that I cannot easily explain. >>> I am currently in the midst of destroy and rebuild of OSDs from >>> filestore to bluestore. >>> With my HDDs, I am seeing expected behavior, but with my SSDs I am >>> seeing unexpected behavior. The HDDs and SSDs are set in crush accordingly. >>> >>> My path to replacing the OSDs is to set the noout, norecover, >>> norebalance flag, destroy the OSD, create the OSD back, (iterate n times, >>> all within a single failure domain), unset the flags, and let it go. It >>> finishes, rinse, repeat. >>> >>> For the SSD OSDs, they are SATA SSDs (Samsung SM863a) , 10 to a node, >>> with 2 NVMe drives (Intel P3700), 5 SATA SSDs to 1 NVMe drive, 16G >>> partitions for block.db (previously filestore journals). >>> 2x10GbE networking between the nodes. SATA backplane caps out at around >>> 10 Gb/s as its 2x 6 Gb/s controllers. Luminous 12.2.2. >>> >>> When the flags are unset, recovery starts and I see a very large rush of >>> traffic, however, after the first machine completed, the performance >>> tapered off at a rapid pace and trickles. Comparatively, I’m getting >>> 100-200 recovery ops on 3 HDDs, backfilling from 21 other HDDs, where as >>> I’m getting 150-250 recovery ops on 5 SSDs, backfilling from 40 other SSDs. >>> Every once in a while I will see a spike up to 500, 1000, or even 2000 ops >>> on the SSDs, often a few hundred recovery ops from one OSD, and 8-15 ops >>> from the others that are backfilling. >>> >>> This is a far cry from the more than 15-30k recovery ops that it started >>> off recovering with 1-3k recovery ops from a single OSD to the backfilling >>> OSD(s). And an even farther cry from the >15k recovery ops I was sustaining >>> for over an hour or more before. I was able to rebuild a 1.9T SSD (1.1T >>> used) in a little under an hour, and I could do about 5 at a time and still >>> keep it at roughly an hour to backfill all of them, but then I hit a >>> roadblock after the first machine, when I tried to do 10 at a time (single >>> machine). I am now still experiencing the same thing on the third node, >>> while doing 5 OSDs at a time. >>> >>> The pools associated with these SSDs are cephfs-metadata, as well as a >>> pure rados object pool we use for our own internal applications. Both are >>> size=3, min_size=2. >>> >>> It appears I am not the first to run into this, but it looks like there >>> was no resolution: >>> https://www.spinics.net/lists/ceph-users/msg41493.html >>> >>> Recovery parameters for the OSDs match what was in the previous thread, >>> sans the osd conf block listed. And current osd_max_backfills = 30 and >>> osd_recovery_max_active = 35. Very little activity on the OSDs during this >>> period, so should not be any contention for iops on the SSDs. >>> >>> The only oddity that I can attribute to things is that we had a few >>> periods of time where the disk load on one of the mons was high enough to >>> cause the mon to drop out of quorum for a brief amount of time, a few >>> times. But I wouldn’t think backfills would just get throttled due to mons >>> flapping. >>> >>> Hopefully someone has some experience or can steer me in a path to >>> improve the performance of the backfills so that I’m not stuck in backfill >>> purgatory longer than I need to be. >>> >>> Linking an imgur album with some screen grabs of the recovery ops over >>> time for the first machine, versus the second and third machines to >>> demonstrate the delta between them. >>> https://imgur.com/a/OJw4b >>> >>> Also including a ceph osd df of the SSDs, highlighted in red are the >>> OSDs currently backfilling. Could this possibly be PG overdose? I don’t >>> ever run into ‘stuck activating’ PGs, its just painfully slow backfills, >>> like they are being throttled by ceph, that are causing me to worry. Drives >>> aren’t worn, <30 P/E cycles on the drives, so plenty of life left in them. >>> >>> Thanks, >>> Reed >>> >>> $ ceph osd df >>> ID CLASS WEIGHT REWEIGHT SIZE USE AVAIL %USE VAR PGS >>> 24 ssd 1.76109 1.00000 1803G 1094G 708G 60.69 1.08 260 >>> 25 ssd 1.76109 1.00000 1803G 1136G 667G 63.01 1.12 271 >>> 26 ssd 1.76109 1.00000 1803G 1018G 785G 56.46 1.01 243 >>> 27 ssd 1.76109 1.00000 1803G 1065G 737G 59.10 1.05 253 >>> 28 ssd 1.76109 1.00000 1803G 1026G 776G 56.94 1.02 245 >>> 29 ssd 1.76109 1.00000 1803G 1132G 671G 62.79 1.12 270 >>> 30 ssd 1.76109 1.00000 1803G 944G 859G 52.35 0.93 224 >>> 31 ssd 1.76109 1.00000 1803G 1061G 742G 58.85 1.05 252 >>> 32 ssd 1.76109 1.00000 1803G 1003G 799G 55.67 0.99 239 >>> 33 ssd 1.76109 1.00000 1803G 1049G 753G 58.20 1.04 250 >>> 34 ssd 1.76109 1.00000 1803G 1086G 717G 60.23 1.07 257 >>> 35 ssd 1.76109 1.00000 1803G 978G 824G 54.26 0.97 232 >>> 36 ssd 1.76109 1.00000 1803G 1057G 745G 58.64 1.05 252 >>> 37 ssd 1.76109 1.00000 1803G 1025G 777G 56.88 1.01 244 >>> 38 ssd 1.76109 1.00000 1803G 1047G 756G 58.06 1.04 250 >>> 39 ssd 1.76109 1.00000 1803G 1031G 771G 57.20 1.02 246 >>> 40 ssd 1.76109 1.00000 1803G 1029G 774G 57.07 1.02 245 >>> 41 ssd 1.76109 1.00000 1803G 1033G 770G 57.28 1.02 245 >>> 42 ssd 1.76109 1.00000 1803G 993G 809G 55.10 0.98 236 >>> 43 ssd 1.76109 1.00000 1803G 1072G 731G 59.45 1.06 256 >>> 44 ssd 1.76109 1.00000 1803G 1039G 763G 57.64 1.03 248 >>> 45 ssd 1.76109 1.00000 1803G 992G 810G 55.06 0.98 236 >>> 46 ssd 1.76109 1.00000 1803G 1068G 735G 59.23 1.06 254 >>> 47 ssd 1.76109 1.00000 1803G 1020G 783G 56.57 1.01 242 >>> 48 ssd 1.76109 1.00000 1803G 945G 857G 52.44 0.94 225 >>> 49 ssd 1.76109 1.00000 1803G 649G 1154G 36.01 0.64 139 >>> 50 ssd 1.76109 1.00000 1803G 426G 1377G 23.64 0.42 83 >>> 51 ssd 1.76109 1.00000 1803G 610G 1193G 33.84 0.60 131 >>> 52 ssd 1.76109 1.00000 1803G 558G 1244G 30.98 0.55 118 >>> 53 ssd 1.76109 1.00000 1803G 731G 1072G 40.54 0.72 161 >>> 54 ssd 1.74599 1.00000 1787G 859G 928G 48.06 0.86 229 >>> 55 ssd 1.74599 1.00000 1787G 942G 844G 52.74 0.94 252 >>> 56 ssd 1.74599 1.00000 1787G 928G 859G 51.94 0.93 246 >>> 57 ssd 1.74599 1.00000 1787G 1039G 748G 58.15 1.04 277 >>> 58 ssd 1.74599 1.00000 1787G 963G 824G 53.87 0.96 255 >>> 59 ssd 1.74599 1.00000 1787G 909G 877G 50.89 0.91 241 >>> 60 ssd 1.74599 1.00000 1787G 1039G 748G 58.15 1.04 277 >>> 61 ssd 1.74599 1.00000 1787G 892G 895G 49.91 0.89 238 >>> 62 ssd 1.74599 1.00000 1787G 927G 859G 51.90 0.93 245 >>> 63 ssd 1.74599 1.00000 1787G 864G 922G 48.39 0.86 229 >>> 64 ssd 1.74599 1.00000 1787G 968G 819G 54.16 0.97 257 >>> 65 ssd 1.74599 1.00000 1787G 892G 894G 49.93 0.89 237 >>> 66 ssd 1.74599 1.00000 1787G 951G 836G 53.23 0.95 252 >>> 67 ssd 1.74599 1.00000 1787G 878G 908G 49.16 0.88 232 >>> 68 ssd 1.74599 1.00000 1787G 899G 888G 50.29 0.90 238 >>> 69 ssd 1.74599 1.00000 1787G 948G 839G 53.04 0.95 252 >>> 70 ssd 1.74599 1.00000 1787G 914G 873G 51.15 0.91 246 >>> 71 ssd 1.74599 1.00000 1787G 1004G 782G 56.21 1.00 266 >>> 72 ssd 1.74599 1.00000 1787G 812G 974G 45.47 0.81 216 >>> 73 ssd 1.74599 1.00000 1787G 932G 855G 52.15 0.93 247 >>> >>> _______________________________________________ >>> 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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