Currently I am running Zentyal Server(Ubuntu) as Guest on a esxi 5 host on a Adaptec raid controller RAID 10 with Enterprise WD hard drives, 8 Core CPU and 8 Gb of ram (I know a bit overkill) to server about 40 Users. Currently 300GB of storage is being used out of 800GB on Thin Provision.
At the start Read/Write Performance was amazing (200MB/s read, 170MB/s write) but as the storage grow performance has come down to 9MB/s read and about 2-3MB/s write using dd and hdparm.
Cannot understand what could cause this, Any help would be appreciated. I have checked CPU and not much of it is being used unless someone is writing to it(maxes out, no antivirus on the server).
This seems to only happen on this Guest as I tried to create another Guest and hdparm and dd returned average 200MBs/170MBs read/write performance.