We're going to install Linux Red Hat enterprise 5.5 on HP blade server that is connected to a part of SAN storage MSA 2000. I've tested both marked and unmarked sda option in partitioning. I did this several times but unfortunately it stuck in the middle of installation. I mean in the last next when red hat goes to format the partition it stuck(in normal way it takes time around 20 minutes but in these installations I let to takes time more than 1 hour) but finally it couldn't work and I restarted it again and install it again! We guess that this model of server cannot match with red hat enterprise 5.5 or 6.1 now I need to be sure about that.
The HP ProLiant BL680 G5 systems are compatible, certified and supported under RHEL 5.x and RHEL 6. How are you performing the installation? Are you using a current CD/ISO? Are you doing this through an ILO session? PXE boot? That may make a difference.
/dev/sda, so I'm assuming you intend to install directly to the MSA2000 SAN. How is the SAN connected? Fibre? SAS? iSCSI? That still should not be an issue, but that information can help.
Are you receiving any errors during the stalled installation? Have you tried any of the other virtual consoles during the installation to try to debug what's happening? Ctrl-Alt-F2 or Alt-F2 should give you a system prompt during the installation. Alt-F3 should show the installation log, while Alt-F4 would display system messages.