Question Poor SSD write performance in RAID1 Intel XEON mainboards

[winacker]

Hi,
I have two Hyper-V SRV16 hosts that run on INTEL on-board RAID1 SSD subsystems.
One of them e.g. has two RAID1 SSD subsystems (Samsung 850 PRO) and one HDD RAID1.
Just by chance I figured that write performance to the SSD is about 30MB/s with 100% disk activity.
I measured with AS-SSD to verify and got conformation: write performance on all SSD is poor (~30MB write, 900MB read), on both hosts. Write performance on HDD is well.
SMART is OK.

What could be wrong/what can I do?
thx

 

[popatim]

write back or write thru?

 

[kanewolf]

What is the performance of your bare metal host? My guess it is the abstraction of the RAID is poor in the VM.

 

[winacker]

Its write through - write back doesn't improve it significantly.
Bare metal performance: tested it without Hyper-V activated, pure SRV16 - lausy too.
The HDD-RAID performance on that same controller is as good as it should be - so what makes SSD write so bad (TRIM is activated).

I really don't have a clue how to tackle that