You can verify your cache policy with MegaCLI tool. Check your output from `MegaCli -CfgDsply -a0' command.
What a cool tool. It looks like it should be active according to MegaCli, though strange that Scott sees his drives in write-back mode via CentOS and I do not and I also have these horrific NFS speeds via VMWare that so many people have found to be caused by write-back not being active...
I don't know what the answer is to this question. I went with iSCSI instead of NFS, the benefits being that it trounces my NFS setup performance wise, and seems stable despite warnings of high I/O causing VMWare to drop the LUN (I tested with bonnie++ as it seems this is an effective tool in getting the LUN to drop in VMWare).
Product Name: PERC 5/i Integrated
Memory: 256MB
BBU: Present ...
Default Cache Policy: WriteBack, ReadAheadNone, Direct, No Write Cache if Bad BBU
Current Cache Policy: WriteBack, ReadAheadNone, Direct, No Write Cache if Bad BBU
Access Policy: Read/Write
Disk Cache Policy: Disk's Default