Hello!
I have installed high available cluster with 1 SAN based on Windows 2012 with hardware RAID-5 (4x2TB disks) and 2 HP servers SE1101.
Currently I have only one VM is being used on this system.
I am expiriencing next problem:
When I copy to this VM's HDD a big file (4GB) it is getting really slow. I can clearly see how the speed is good at the begining (caching?) and than starts dropping (after 15%). The speed is falling to 14 MBps. When I am copying big file from this VM the speed is constantly 110+ MBps.
I know that RAID is pretty much fast and should go 200+ MBps on write. If I add 4GB of RAM to VM the file is copying quicker until 75% than there is a slow down. I have also monitored the memory in this case and it appears the VM is still flushing the cash long after copying has been finished.
I have 2 iSCSI 1Gbps interfaces that are going to SAN. I see them blinking when the file is being copying. And I have 4x1Gbps NICs on SAN. Jumbo frames are enabled and cards are working on 1Gbps Full Duplex.
Can someone explain me how to fix it? I would like to get at least 100MBps on write speed.
Thank you!