MSA2000's vdisks fault-tolerance behavior vs. Virtual Server's VMs

[Fabio_S]

Hello,
I have a few BL460 blades connected to a MSA2212 FC SAN. In the MSA I have two enclosures, each with 12 SAS hard disks.
I have created 4 vdisks, all in RAID10; each of them uses 6 hard disks (3 from an enclosure, 3 from the other one). No spare disks.

Now, one of the blades is a WS2003 machine working as Microsoft Virtual Server host (Virtual Server installed on C: drive, not in the SAN). I have created 10 volumes on the SAN (not all on the same vdisk), and linked them to this host. One volume per virtual machine.

Today one hard disk failed.
While I expected impacts only on the vdisk this HDD is member of, all the vdisks were impacted (general poor response time on all the volumes linked to the blades). But that is maybe acceptable.
What I don't understand is why all the virtual machines became totally unresponsive, even if placed in volumes not created in the affected vdisk.
And if i try to reboot them (the VMs), I often get "no boot disk found", as if the VHD is corrupt, but then if I move the VHD on a disk outside of the SAN, it works fine.
Is this normal?
Is there any configuration I can apply to the SAN so not to have such a behavior if a single disk fails?

thanks,

fabio