SAN disk could not be written - freebsd 8

[Xi W Wu]

Hi,guys

When I attached a SAN(storage attached network) disk to freebsd 8, then
write some files to it, I got this error message:
g_vfs_done(): da1s1d[WRITE(offset=275xxxxxx, length=2048/4096)] error = 5
and thing get even worse, once I benchmark the san-disk, system hung.

I'm wondering what went wrong? does freebsd could not use san-disk?

my environment:
IBM Bladecenter S + HS22 blade server
SAN disk was mapped from RSSM module, which is a raided sas switch.