Hi,
On 12.08.2017 20:50, Paul Kraus wrote:
On Aug 11, 2017, at 2:28 AM, Eugene M. Zheganin <e...@norma.perm.ru> wrote:
Why does the zfs listing eat so much of the CPU ?
47114 root 1 20 0 40432K 3840K db->db 4 0:05 26.84% zfs
47099 root 1 20 0 40432K 3840K zio->i 17 0:05 26.83% zfs
47106 root 1 20 0 40432K 3840K db->db 21 0:05 26.81% zfs
47150 root 1 20 0 40432K 3428K db->db 13 0:03 26.31% zfs
47141 root 1 20 0 40432K 3428K zio->i 28 0:03 26.31% zfs
47135 root 1 20 0 40432K 3312K g_wait 9 0:03 25.51% zfs
This is from winter 2017 11-STABLE (r310734), one of the 'zfs'es is cloning,
and all the others are 'zfs list -t all'. I have like 25 gigs of free RAM, do I
have any chance of speeding this up using may be some caching or some sysctl
tuning ? We are using a simple ZFS web API that may issue concurrent or
sequential listing requests, so as you can see they sometimes do stack.
How many snapshots do you have ? I have only seen this behavior with LOTS (not
hundreds, but thousands) of snapshots.
[root@san1:~]# zfs list -t snapshot | wc -l
88
What does your `iostat -x 1` look like ? I expect that you are probably
saturating your drives with random I/O.
Well, it's really long, and the disks are busy with random i/o indeed,
but byst only for 20-30%. As about iostat - it's really long, because I
have hundreds (not thousands) of zvols, and they do show up in iostat
-x. But nothing unusual besides that.
Thanks.
Eugene.
_______________________________________________
freebsd-stable@freebsd.org mailing list
https://lists.freebsd.org/mailman/listinfo/freebsd-stable
To unsubscribe, send any mail to "freebsd-stable-unsubscr...@freebsd.org"
