[ Thanks to jmalasko for this link.
]
“This article shows you how to boot from SAS storage
(in this case, the IBM System Storage DS3200) using the IBM
BladeCenter-H and x86-based BladeCenter HS21 and LS21 servers. (For
BladeCenter-E, check the blade compatibility matrix listed below in
the Resources section to see if your environment is supported.) You
will also see how to enable multipathing in Linux. Multipathing, or
multipath I/O, is a fault-tolerance and performance enhancement
technique where more than one physical path exists between the CPU
and its mass storage devices. Simple examples are a SCSI disk
connected to two SCSI controllers on the same computer or a disk
connected to two Fibre Channel ports.“The major advantage of using external storage only is the
improved availability of the server. Even though you can configure
several different RAID levels using local disks within the blade
only, you must shut down the system to replace a defective drive.
Using external storage and hot-swap drives, you can replace
defective drives without interrupting services. Recently, IBM
announced blade servers, the BladeCenter HS12 and JS12 servers,
with support for hot-swap SAS drives, but both are uniprocessor
machines only.”