ZFS send problem

[Albert Shih]

Hi,

I still got a very serious problem with zfs send (not recv).

After I take a snapshot and try to send it, the server begin to send the
snapshot (I can see on the target the incomming data) and after sometime
(5=10m) on the server the zfs command freeze, I can launch zpool command
either.

I check arc size, and if I let the max amount of memory to the
vfs.zfs.arc_max (~ Max RAM ~ 192Go) the zfs command freeze simultaneously
with the arc reach 100.3% of the max  (but I cannot make lots of test, so
I'm not sure it's related).

If I set le vfs.zfs.arc_max at half of the RAM ( = 96Go) I can see thought
zfs-stats the arc come to 100.3% and empty to 98-99% and raise again.
Either way the zfs command not really freeze totally but take lot of time
to answer (~10-20 seconds when normally it's < 1sec).

The only « special » configuration (vs my other server doing same thing
without problem) is I got two zpool on this one. I've no idea if that can
be a problem (one with 2 ssd, the other with 4 vdev of 7 disks)

I check dmesg, /var/log/all.log and don't find any information or error
message.

Any idea ?

Regards.

--
Albert SHIH
DIO bâtiment 15
Observatoire de Paris
xmpp: jas at obspm.fr
Heure local/Local time:
Thu Jun 14 19:46:04 CEST 2018