HP StorageWorks Scalable File Share System Installation and Upgrade Guide Version 2.2

Overview1–12
1.4.2 Topology in systems using SFS20 storage arrays
The SFS20 array is a serial ATA (SATA) 1.5 Gb/s disk drive storage array with Ultra320 SCSI host
connectivity. The SCSI ports of each SFS20 array connect to Smart Array HBAs on each server. The array
can contain up to 12 SATA drives configured with RAID5 or ADG redundancy, and presents storage to the
Object Storage Servers over a SCSI interconnect. The administration and MDS server pair can be
configured with either two or four SFS20 arrays, while each Object Storage Server pair can be configured
with up to eight SFS20 arrays. However, all of the Object Storage Server pairs in the HP SFS system must
be configured with the same number of arrays.
The SFS20 has two ports; one port connects to the first server in a server pair, while the second port connects
to the second server in the server pair. The SFS20 array must be connected to the same port on each of the
two servers—that is, if an SFS20 array is attached to port A1 on the Smart Array 6404 HBA on the first
server in the pair, it must also be attached to port A1 on the Smart Array 6404 HBA on the second server
in the pair.
Note that the RAID function in systems using SFS20 arrays is performed by the SFS20 arrays and not by the
Smart Array 6404 HBAs, thus allowing high performance, as hardware RAID operations occur in parallel
on all active arrays.
Two types of configuration are possible in systems using SFS20 storage, as follows:
• Dual-connected SFS20 arrays (see Section 1.4.2.1).
• Mirrored dual-connected SFS20 arrays (see Section 1.4.2.2).
Table 1-2 shows the configurations that are possible for an Object Storage Server pair, based on the number
of SFS20 arrays connected to each server in the server pair. Depending on the number of arrays per server,
software RAID mirroring may be an option.
For detailed information on configuring LUNs on SFS20 arrays, see Chapter 5 and Chapter 7.
Table 1-2 SFS20 Object Storage Server configurations
Configuration Total Number of SFS20
Arrays
Software RAID Mirroring Number of Smart Array
6404 HBAs per Server
A2No1
B4Optional1
C6No2
D8Optional2