High Write Latency

Hi,

I have two ESXi 4.1 U1 and a Huawei S2600 storage and the physical write and device command lantency is high (see attached files)

The storage is connected directly to the servers through iSCSI with Jumbo Frames and Round Robin. I'm using a Raid 5 with four SAS 15k disks and the VM's are in a LUN in this Raid

I have 19 VM's distributed between the two hosts and 4 of them is using 2 vCPU's

Any ideas of where is the problem?

Thanks