Hi, On Wed, Mar 18, 2015 at 12:21 PM, Steven Jones <steven.jones1201@xxxxxxxxxxx> wrote: > Hi, > iostat -x snapshot: > > avg-cpu: %user %nice %system %iowait %steal %idle > 0.50 0.00 2.35 15.09 0.00 82.05 > > 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 5.00 0.00 2056.00 822.40 > 0.00 0.00 0.00 0.00 0.00 0.00 > sdb 0.00 0.00 1055.00 549.00 41166.50 22840.00 79.81 > 5.28 3.28 4.94 0.10 0.62 100.00 Your sdb is saturated... > --- > iotop snapshot: > Total DISK READ: 41.63 M/s | Total DISK WRITE: 31.43 M/s > TID PRIO USER DISK READ DISK WRITE SWAPIN IO> COMMAND > 32101 be/4 postgres 10.25 M/s 1085.86 K/s 0.00 % 96.80 % postgres: > checkpointer process > 56661 be/4 postgres 6.84 M/s 591.61 K/s 0.00 % 90.91 % postgres: > dbauser db [local] COPY > 32102 be/4 postgres 8.05 M/s 1340.47 K/s 0.00 % 82.47 % postgres: writer > process > 1005 be/0 root 0.00 B/s 0.00 B/s 0.00 % 5.81 % [txg_sync] > 32103 be/4 postgres 0.00 B/s 10.41 M/s 0.00 % 0.52 % postgres: wal > writer process Why are checkpointer process and writer process reading at 18 MB/s ? I have no experience with zfs but could it be related to COW and recordsize? I have no idea if these reads are counted in iotop output though. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
