High IO Delay / Low FSYNCS/SECOND

[jpp04]

Hello,

The server is running with Intel(R) Xeon(R) CPU D-1531 @ 2.20GHz and 32Gb of RAM.
It uses Proxmox 6.1.7 and we're currently facing poor IO performance when there is bit of load. IO delay is sometimes > 25%.
We're using MDADM RAID1 with 2x Samsung SSD PM871b
Here is pveperf result with no VMs running:

CPU BOGOMIPS:      52794.84
REGEX/SECOND:      2720682
HD SIZE:           467.55 GB (/dev/md1)
BUFFERED READS:    466.71 MB/sec
AVERAGE SEEK TIME: 0.14 ms
FSYNCS/SECOND:     255.45
DNS EXT:           13.46 ms

If I start VMs, FSYNCS/SECOND can decrease to 3...

The server is using a fresh install. There are just 2 Linux VMs running on it. Proxmox 6.1.7 is running on it.

Filesystem type is ext4
/dev/md1 / ext4 rw,relatime,errors=remount-ro 0 0 (system + data disk)
/dev/md0 /boot ext4 rw,relatime 0 0 (boot disk)

What to do to improve performance ?

Thanks

 

[wolfgang]

Hi,

we do not support MDRaid.
We only support ZFS as SWRaid or you can use HWRaid instead.