zfs, a directory that used to hold lot of files and listing pause

[Jonathan Chen]

On 21 October 2016 at 12:56, Steven Hartland <killing at multiplay.co.uk> wrote:
[...]
> When you see the stalling what does gstat -pd and top -SHz show?

On my dev box:

1:38pm# uname -a
FreeBSD irontree 10.3-STABLE FreeBSD 10.3-STABLE #0 r307401: Mon Oct
17 10:17:22 NZDT 2016     root at irontree:/usr/obj/usr/src/sys/GENERIC
amd64
1:49pm# gstat -pd
dT: 1.004s  w: 1.000s
 L(q)  ops/s    r/s   kBps   ms/r    w/s   kBps   ms/w    d/s   kBps
ms/d   %busy Name
    0      0      0      0    0.0      0      0    0.0      0      0
 0.0    0.0| cd0
   18    618      1    128   41.4    606  52854   17.2      0      0
 0.0  100.5| ada0
^C
1:49pm# top -SHz
last pid: 83284;  load averages:  0.89,  0.68,  0.46
                                                                 up
4+03:11:32  13:49:05
565 processes: 9 running, 517 sleeping, 17 zombie, 22 waiting
CPU:  3.7% user,  0.0% nice,  1.9% system,  0.0% interrupt, 94.3% idle
Mem: 543M Active, 2153M Inact, 11G Wired, 10M Cache, 2132M Free
ARC: 7249M Total, 1325M MFU, 4534M MRU, 906M Anon, 223M Header, 261M Other
Swap: 32G Total, 201M Used, 32G Free

  PID USERNAME   PRI NICE   SIZE    RES STATE   C   TIME    WCPU COMMAND
83149 postgres    38    0  2197M   528M zio->i  5   1:13  23.19% postgres
83148 jonc        22    0 36028K 13476K select  2   0:11   3.86% pg_restore
  852 postgres    20    0  2181M  2051M select  5   0:27   0.68% postgres
    0 root       -15    -     0K  4240K -       6   0:50   0.49%
kernel{zio_write_issue_}
    0 root       -15    -     0K  4240K -       6   0:50   0.39%
kernel{zio_write_issue_}
    0 root       -15    -     0K  4240K -       6   0:50   0.39%
kernel{zio_write_issue_}
    0 root       -15    -     0K  4240K -       7   0:50   0.39%
kernel{zio_write_issue_}
    0 root       -15    -     0K  4240K -       7   0:50   0.39%
kernel{zio_write_issue_}
    0 root       -15    -     0K  4240K -       7   0:50   0.29%
kernel{zio_write_issue_}
    3 root        -8    -     0K   112K zio->i  6   1:50   0.20%
zfskern{txg_thread_enter}
   12 root       -88    -     0K   352K WAIT    0   1:07   0.20%
intr{irq268: ahci0}
    0 root       -16    -     0K  4240K -       4   0:29   0.20%
kernel{zio_write_intr_4}
    0 root       -16    -     0K  4240K -       7   0:29   0.10%
kernel{zio_write_intr_6}
    0 root       -16    -     0K  4240K -       0   0:29   0.10%
kernel{zio_write_intr_1}
    0 root       -16    -     0K  4240K -       5   0:29   0.10%
kernel{zio_write_intr_2}
    0 root       -16    -     0K  4240K -       1   0:29   0.10%
kernel{zio_write_intr_5}
...

Taking another look at the internal dir structure for postgres, I'm
not too sure whether this is related to the original poster's problem
though.

Cheers.
-- 
Jonathan Chen <jonc at chen.org.nz>