>>> Eric Robinson <[email protected]> schrieb am 02.08.2017 um 23:20 in Nachricht <dm5pr03mb2729c66cec1e3b8b9e297185fa...@dm5pr03mb2729.namprd03.prod.outlook.com>
> 1) iotop did not show any significant io, just maybe 30k/second of drbd > traffic. > > 2) okay. I've never done that before. I'll give it a shot. > > 3) I'm not sure what I'm looking at there. See /usr/src/linux/Documentation/block/stat.txt ;-) I wrote an NRPE plugin to monitor those with performance data and verbose text output, e.g.: CFS_VMs-xen: [delta 120s], 1.15086 IO/s read, 60.7789 IO/s write, 0 req/s read merges, 0 req/s write merges, 4.53674 sec/s read, 486.231 sec/s write, 2.36844 ms/s read wait, 2702.19 ms/s write wait, 0 req in_flight, 115.987 ms/s active, 2704.53 ms/s wait Regards, Ulrich > > -- > Eric Robinson > >> -----Original Message----- >> From: Ulrich Windl [mailto:[email protected]] >> Sent: Tuesday, August 01, 2017 11:28 PM >> To: [email protected] >> Subject: [ClusterLabs] Antw: DRBD and SSD TRIM - Slow! >> >> Hi! >> >> I know little about trim operations, but you could try one of these: >> >> 1) iotop to see whether some I/O is done during trimming (assuming >> trimming itself is not considered to be I/O) >> >> 2) Try blocktrace on the affected devices to see what's going on. It's hard > to >> set up and to extract the info you are looking for, but it provides deep >> insights >> >> 3) Watch /sys/block/$BDEV/stat for performance statistics. I don't know how >> well DRBD supports these, however (e.g. MDRAID shows no wait times and >> no busy operations, while a multipath map has it all). >> >> Regards, >> Ulrich >> >> >>> Eric Robinson <[email protected]> schrieb am 02.08.2017 um >> >>> 07:09 in >> Nachricht >> <[email protected] >> d03.prod.outlook.com> >> >> > Does anyone know why trimming a filesystem mounted on a DRBD volume >> > takes so long? I mean like three days to trim a 1.2TB filesystem. >> > >> > Here are some pertinent details: >> > >> > OS: SLES 12 SP2 >> > Kernel: 4.4.74-92.29 >> > Drives: 6 x Samsung SSD 840 Pro 512GB >> > RAID: 0 (mdraid) >> > DRBD: 9.0.8 >> > Protocol: C >> > Network: Gigabit >> > Utilization: 10% >> > Latency: < 1ms >> > Loss: 0% >> > Iperf test: 900 mbits/sec >> > >> > When I write to a non-DRBD partition, I get 400MB/sec (bypassing caches). >> > When I trim a non-DRBD partition, it completes fast. >> > When I write to a DRBD volume, I get 80MB/sec. >> > >> > When I trim a DRBD volume, it takes bloody ages! >> > >> > -- >> > Eric Robinson >> >> >> >> >> >> _______________________________________________ >> Users mailing list: [email protected] >> http://lists.clusterlabs.org/mailman/listinfo/users >> >> Project Home: http://www.clusterlabs.org Getting started: >> http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf >> Bugs: http://bugs.clusterlabs.org > > _______________________________________________ > Users mailing list: [email protected] > http://lists.clusterlabs.org/mailman/listinfo/users > > Project Home: http://www.clusterlabs.org > Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf > Bugs: http://bugs.clusterlabs.org _______________________________________________ Users mailing list: [email protected] http://lists.clusterlabs.org/mailman/listinfo/users Project Home: http://www.clusterlabs.org Getting started: http://www.clusterlabs.org/doc/Cluster_from_Scratch.pdf Bugs: http://bugs.clusterlabs.org
