High IO-delay on server

[deeq]

I have problems with my proxmox server (pve-manager/4.1-5/f910ef5c (running kernel: 4.2.6-1-pve)), Problem is high io delay, server hangs at (20-70%) and almost constant delay is (5-10%).

Server is hetzner i7-3770 12G RAM with 2 SATA hard drive software RAID1, with 2 LXC containers. I already tried to set containers quota to 0 with vzdump/pct restore, no improvement.

I'm desperate, please help, I do not know what to do. I have had the same server for long time and never had this kind problem, it started about 2-4 weeks ago and now io-delay is getting out of the hands.

 

[chronos]

What disk usage tools executed on host OS say?
apt-get install atop and then run atop and then press d key for disk usage view
apt-get install iotop and then run iotop

 

[pizza]

Do you use ZFS for softraid1 or mdraid?