sos on cyrusimapd

[Albert Shih]

Le 27/06/2018 à 12:58:22-0400, Eric W. Bates a écrit

Hi,

Thanks you *very* much for your answer.

I will try that. But I'm know pretty sure that the problem doesn't come
from network but from I/O of the disk.

I manage to configure my mutt (my old MUA) to keep the connection, he lost
the connection because by default he keep the connection only for 15
secondes. Changing that to 600 secondes and I never get disconnected.

But I still get some hang (10-30 sec) and I think it's the I/O because the
server hang too or at least very slow down (when I'm connected by ssh) and
If I use atop I'm see the disk are busy.

Another point is during those time (~1500 connections for ~500 uniques
users), the ARC go down to 20G (by configuration it's get 96Go).

I will try the zfs tweaking.


>
> kern.ipc.maxsockbuf=4194304 # (default 2097152)
> net.inet.tcp.sendbuf_max=4194304  # (default 2097152)
> net.inet.tcp.recvbuf_max=4194304  # (default 2097152)
> net.inet.tcp.mssdflt=1460  # (default 536)
> net.inet.tcp.minmss=1300   # (default 216)
> net.inet.tcp.cc.algorithm=htcp  # (default newreno)
> net.inet.tcp.cc.htcp.adaptive_backoff=1 # (default 0 ; disabled)
> net.inet.tcp.cc.htcp.rtt_scaling=1 # (default 0 ; disabled)
> net.inet.tcp.syncache.rexmtlimit=0  # (default 3)
> net.inet.ip.rtexpire=10      # (default 3600)
> net.inet.tcp.syncookies=0  # (default 1)
> net.inet.tcp.tso=0   # (default 1)
>
> kern.ipc.soacceptqueue=32768  # (default 128 ; same as kern.ipc.somaxconn)
> net.inet.tcp.delayed_ack=0
>
> Been quite a while since we set all that up and it's been performing well.

well, from thunderbird point of vu everything seem fine, only some *normal*
slow down, users doesn't complain.

I complain because it's big server with lot of disk (24 disks, 2 SSD for
/var/imap, RAM 192Go), so....I like to make it very efficient

And again thanks you for your help.

Regards.




--
Albert SHIH
DIO bâtiment 15
Observatoire de Paris
xmpp: jas at obspm.fr
Heure local/Local time:
Thu Jun 28 22:35:43 CEST 2018