Raid 10 - choices for a better Virtualization setup

[Baredor]

I'm planning a VMware server on a 2U box, so fast I/O is my main concern here. My options are 6x 3.5 disks or 8x 2.5 disks. 2 disks set aside for the OS mirror, so that leaves my options for the VM partiton as the following:

Raid 10

4x 3.5" 10K rpm 146GB
6x 2.5" 10K rpm 73GB

Obviously I will take a large hit in disk space by using the 2.5" drives, but would the RAID 10 perform significantly better with 6 disks instead of 4?

I can make the 3.5s into 15k rpm as well. Is this preferable over the 6 2.5s?

Comments appreciated.

[venm11]

hmm... 2.5" drives are quite a bit slower than 3.5"s for raw throughput (less surface area per rotation). I think fujitsu makes 10-15k 2.5s, but ... less performance & capacity at much higher cost? (even with 6x drives).

I guess it depends on what you're doing with the VMs. I've been running vmware with 2x 38gb 15ks and didn't notice any difference over 2x 320gb 7200mb IDEs. (tangent: a narrow partition on higher density platters seem to perform same/better in "normal" loads than lower density scsi drives, but may not be true for pure random accesses).

Btw... what controller are you using for this?

[Baredor]

Btw... what controller are you using for this?

Dell PERC5/i

Most of the VMs will be doing light duty machines that do some "burst" work on a set schedule. These are mostly FTP and EDI boxes, MQseries, a 4th domain controller, and possibly other stuff like WSUS or something - probably 10-12 VMs in all. Nothing heavy like SQL or Exchange. I think you basically gave me my answer, but interested to learn more if anyone else can comment. :)