On 07/31/2017 01:29 PM, Jianjian Huo wrote:
On Sat, Jul 29, 2017 at 8:34 PM, Mark Nelson <mark.a.nelson@xxxxxxxxx> wrote:On 07/28/2017 03:57 PM, Jianjian Huo wrote:Hi Mark, On Wed, Jul 26, 2017 at 8:55 PM, Mark Nelson <mark.a.nelson@xxxxxxxxx> wrote:yeah, metrics and profiling data would be good at this point. The standard gauntlet of collectl/iostat, gdbprof or poorman's profiling, perf, blktrace, etc. Don't necessarily need everything but if anything interesting shows up it would be good to see it. Also, turning on rocksdb bloom filters is worth doing if it hasn't been done yet (happening in master soon via https://github.com/ceph/ceph/pull/16450). FWIW, I'm tracking down what I think is a sequential write regression vs earlier versions of bluestore but haven't figured out what's going on yet or even how much of a regression we are facing (these tests are on much bigger volumes than previously tested). MarkFor bluestore sequential writes, from our testing with master branch two days ago, ec sequential writes (16K and 128K) were 2~3 times slower than 3x sequential writes. From your earlier testing, bluestore ec sequential writes were faster than 3x in all IO size cases. Is this some sort of regression you are aware of? JianjianI wouldn't necessarily expect small EC sequential writes to necessarily do well vs 3x replication. It might depend on the disk configuration and definitely on client side WB cache (This is tricky because RBD cache has some locking limitations that become apparent at high IOPS rates / volume). For large writes though I've seen EC faster (somewhere between 2x and 3x replication). These numbers are almost 5 months old now (and there have been some bluestore performance improvements since then), but here's what I was seeing for RBD EC overwrites last March (scroll to the right for graphs): https://drive.google.com/uc?export=download&id=0B2gTBZrkrnpZbE50QUdtZlBxdFUThanks for sharing this data, Mark. From your data of last March, for RBD EC overwrite on NVMe, EC sequential writes are faster than 3X for all IO sizes including small 4K/16KB. Is this right? but I am not seeing this on my setup(all nvme drives, 12 of them per node), in my case EC sequential writes are 2~3 times slower than 3X. Maybe I have too many drives per node? Jianjian
Maybe, or maybe it's a regression! I'm focused on the bitmap allocator right now, but if I have time I'll try to reproduce those older test results on master. Maybe if you have time, see if you have the same results if you try bluestore from Jan/Feb?
Mark
FWIW, the regression I might be seeing (if it is actually a regression) appears to be limited to RBD block creation rather than writes to existing blocks. IE pre-filling volumes is slower than just creating objects via rados bench of the same size. It's pretty limited in scope. MarkOn 07/26/2017 09:40 PM, Brad Hubbard wrote:Bumping this as I was talking to Junqin in IRC today and he reported it is still an issue. I suggested analysis of metrics and profiling data to try to determine the bottleneck for bluestore and also suggested Junqin open a tracker so we can investigate this thoroughly. Mark, Did you have any additional thoughts on how this might best be attacked? On Thu, Jul 13, 2017 at 11:37 PM, Junqin JQ7 Zhang <zhangjq7@xxxxxxxxxx> wrote:Hi Mark, Thanks for your reply. Our SSD model is: Device Model: SSDSC2BA800G4N Intel SSD DC S3710 Series 800GB And BlueStore OSD configure is as I posted before [osd.0] host = ceph-1 osd data = /var/lib/ceph/osd/ceph-0 # a 100M SSD partition bluestore block db path = /dev/sda5 # a 10G SSD partition bluestore block wal path = /dev/sda6 # a 10G SSD partition bluestore block path = /dev/sdd # a HDD disk The iostat is a quick snapshot of terminal screen on a 8K write. I forget the detail test configuration. I only can make sure is it is a 8K random write. But we have re-setup the cluster, so I can't get the data right now, but we will do test again later these days. Is there any special configure on BlueStore on your lab test? Like, how BlueStore OSD configured in your lab test? Or could you share lab test BlueStore configuration? Like file ceph.conf? Thanks a lot! B.R. Junqin Zhang -----Original Message----- From: ceph-devel-owner@xxxxxxxxxxxxxxx [mailto:ceph-devel-owner@xxxxxxxxxxxxxxx] On Behalf Of Mark Nelson Sent: Wednesday, July 12, 2017 11:29 PM To: Junqin JQ7 Zhang; Mark Nelson; Ceph Development Subject: Re: Ceph Bluestore OSD CPU utilization Hi Junqin On 07/12/2017 05:21 AM, Junqin JQ7 Zhang wrote:Hi Mark, We also compared iostat of filestore and bluestore. Disk write rate of bluestore is only around 10% of filestore in same test case. Here is FileStore iostat during write avg-cpu: %user %nice %system %iowait %steal %idle 13.06 0.00 9.84 11.52 0.00 65.58 Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await r_await w_await svctm %util sda 0.00 0.00 0.00 8196.00 0.00 73588.00 17.96 0.52 0.06 0.00 0.06 0.04 31.90 sdb 0.00 0.00 0.00 8298.00 0.00 75572.00 18.21 0.54 0.07 0.00 0.07 0.04 33.00 sdh 0.00 4894.00 0.00 741.00 0.00 30504.00 82.33 207.60 314.51 0.00 314.51 1.35 100.10 sdj 0.00 1282.00 0.00 938.00 0.00 15652.00 33.37 14.40 16.04 0.00 16.04 0.90 84.10 sdk 0.00 5156.00 0.00 847.00 0.00 34560.00 81.61 199.04 283.83 0.00 283.83 1.18 100.10 sdd 0.00 6889.00 0.00 729.00 0.00 38216.00 104.84 138.60 198.14 0.00 198.14 1.37 100.00 sde 0.00 6909.00 0.00 763.00 0.00 38608.00 101.20 139.16 190.55 0.00 190.55 1.31 100.00 sdf 0.00 3237.00 0.00 708.00 0.00 30548.00 86.29 175.15 310.36 0.00 310.36 1.41 99.80 sdg 0.00 4875.00 0.00 745.00 0.00 32312.00 86.74 207.70 291.26 0.00 291.26 1.34 100.00 sdi 0.00 7732.00 0.00 812.00 0.00 42136.00 103.78 140.94 181.96 0.00 181.96 1.23 100.00 Here is BlueStore iostat during write avg-cpu: %user %nice %system %iowait %steal %idle 6.50 0.00 3.22 2.36 0.00 87.91 Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await r_await w_await svctm %util sda 0.00 0.00 0.00 2938.00 0.00 25072.00 17.07 0.14 0.05 0.00 0.05 0.04 12.70 sdb 0.00 0.00 0.00 2821.00 0.00 26112.00 18.51 0.15 0.05 0.00 0.05 0.05 12.90 sdh 0.00 1.00 0.00 510.00 0.00 3600.00 14.12 5.45 10.68 0.00 10.68 0.24 12.00 sdj 0.00 0.00 0.00 424.00 0.00 3072.00 14.49 4.24 10.00 0.00 10.00 0.22 9.30 sdk 0.00 0.00 0.00 496.00 0.00 3584.00 14.45 4.10 8.26 0.00 8.26 0.18 9.10 sdd 0.00 0.00 0.00 419.00 0.00 3080.00 14.70 3.60 8.60 0.00 8.60 0.19 7.80 sde 0.00 0.00 0.00 650.00 0.00 3784.00 11.64 24.39 40.19 0.00 40.19 1.15 74.60 sdf 0.00 0.00 0.00 494.00 0.00 3584.00 14.51 5.92 11.98 0.00 11.98 0.26 12.90 sdg 0.00 0.00 0.00 493.00 0.00 3584.00 14.54 5.11 10.37 0.00 10.37 0.23 11.20 sdi 0.00 0.00 0.00 744.00 0.00 4664.00 12.54 121.41 177.66 0.00 177.66 1.35 100.10 sda and sdb are SSD, other are HDD.earlier it looked like you were posting the configuration for an 8k randrw test, but this is a pure write test? Can you provide the test configuration for these results? Also, the SSD model would be useful to know. Having said that, these results look pretty different than what I typically see in the lab. A big clue is the avgrq-sz. On filestore you are seeing much larger write requests than with bluestore. That might indicate that metadata writes are going to the HDD. Is this still with the 10GB DB partition? Mark-----Original Message----- From: Junqin JQ7 Zhang Sent: Wednesday, July 12, 2017 10:45 AM To: 'Mark Nelson'; Mark Nelson; Ceph Development Subject: RE: Ceph Bluestore OSD CPU utilization Hi Mark, Actually, we tested filestore on same Ceph version v12.1.0 and same cluster. # ceph -v ceph version 12.1.0 (262617c9f16c55e863693258061c5b25dea5b086) luminous (dev) CPU utilization of each OSD on filestore can reach max to around 200%, but CPU utilization of OSD on bluestore is only around 30%. Then, BlueStore's performance is only about 20% of filestore. We think there must be something wrong with our configuration. I tried to change ceph config, like osd op threads = 8 osd disk threads = 4 but still can't get a good result. Any idea of this? BTW. We changed some filestore related configured during test filestore fd cache size = 2048576000 filestore fd cache shards = 16 filestore async threads = 0 filestore max sync interval = 15 filestore wbthrottle enable = false filestore commit timeout = 1200 filestore_op_thread_suicide_timeout = 0 filestore queue max ops = 1048576 filestore queue max bytes = 17179869184 max open files = 262144 filestore fadvise = false filestore ondisk finisher threads = 4 filestore op threads = 8 Thanks a lot! B.R. Junqin Zhang -----Original Message----- From: ceph-devel-owner@xxxxxxxxxxxxxxx [mailto:ceph-devel-owner@xxxxxxxxxxxxxxx] On Behalf Of Mark Nelson Sent: Tuesday, July 11, 2017 11:47 PM To: Junqin JQ7 Zhang; Mark Nelson; Ceph Development Subject: Re: Ceph Bluestore OSD CPU utilization On 07/11/2017 10:31 AM, Junqin JQ7 Zhang wrote:Hi Mark, Thanks for your reply. The hardware is as below for each 3 hosts. 2 SATA SSD and 8 HDDThe model of SSD potentially could be very important here. The devices we test in our lab are enterprise grade SSDs with power loss protection. That means they don't have to flush data on sync requests. O_DSYNC writes are much faster as a result. I don't know how bad of an impact this has on rocksdb wal/db, but it definitely hurts with filestore journals.Intel(R) Xeon(R) CPU E5-2630 v4 @ 2.20GHz Network: 20000Mb/s I configured OSD like [osd.0] host = ceph-1 osd data = /var/lib/ceph/osd/ceph-0 # a 100M partition of SSD bluestore block db path = /dev/sda5 # a 10G partition of SSDBluestore automatically roles rocksdb data over to the HDD with the db gets full. I bet with 10GB you'll see good performance at first and then you'll start seeing lots of extra reads/writes on the HDD once it fills up with metadata (the more extents that are written out the more likely you'll hit this boundary). You'll want to make the db partitions use the majority of the SSD(s).bluestore block wal path = /dev/sda6 # a 10G partition of SSDThe WAL can be smaller. 1-2GB is enough (potentially even less if you adjust the rocksdb buffer settings, but 1-2GB should be small enough to devote most of your SSDs to DB storage).bluestore block path = /dev/sdd # a HDD disk We use fio to test one or more 100G RBDs, an example of our fio config [global] ioengine=rbd clientname=admin pool=rbd rw=randrw bs=8k runtime=120 iodepth=16 numjobs=4with the rbd engine I try to avoid numjobs as it can give erroneous results in some cases. it's probably better generally to stick with multiple independent fio processes (though in this case for a randrw workload it might not matter).direct=1 rwmixread=0 new_group group_reporting [rbd_image0] rbdname=testimage_100GB_0 Any suggestion?What kind of performance are you seeing and what do you expect to get? MarkThanks. B.R. Junqin zhang -----Original Message----- From: Mark Nelson [mailto:mnelson@xxxxxxxxxx] Sent: Tuesday, July 11, 2017 7:32 PM To: Junqin JQ7 Zhang; Ceph Development Subject: Re: Ceph Bluestore OSD CPU utilization Ugh, small sequential *reads* I meant to say. :) Mark On 07/11/2017 06:31 AM, Mark Nelson wrote:Hi Junqin, Can you tell us your hardware configuration (models and quantities of cpus, network cards, disks, ssds, etc) and the command and options you used to measure performance? In many cases bluestore is faster than filestore, but there are a couple of cases where it is notably slower, the big one being when doing small sequential writes without client-side readahead. Mark On 07/11/2017 05:34 AM, Junqin JQ7 Zhang wrote:Hi, I installed Ceph luminous v12.1.0 in 3 nodes cluster with BlueStore and did some fio test. During test, I found the each OSD CPU utilization rate was only aroud 30%. And the performance seems not good to me. Is there any configuration to help increase OSD CPU utilization to improve performance? Change kernel.pid_max? Any BlueStore specific configuration? Thanks a lot! B.R. 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