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

SFS20 storage — overview and planning 5–19
5.3 SFS20 storage — overview and planning
The SFS20 array is a serial ATA (SATA) 1.5 Gb/s disk drive storage array with Ultra320 SCSI host
connectivity. It has two ports and can be connected to two servers. The administration and MDS server pair
can be connected to up to a maximum of four SFS20 arrays, while an Object Storage Server pair can be
connected to up to a maximum of eight SFS20 arrays.
You will configure the SFS20 storage during the system installation. The information and examples in this
section are provided to help you to plan how you will use your SFS20 storage. Use the worksheets in
Table B-8 and Table B-10 (one copy of this worksheet for each array) in Appendix B to record the details
of your storage configuration.
This section is organized as follows:
• SFS20 storage concepts (Section 5.3.1)
• LUN roles (Section 5.3.2)
• ADG and RAID5 redundancy (Section 5.3.3)
• Configuring SFS20 arrays attached to the administration and MDS servers (Section 5.3.4)
• Configuring SFS20 arrays attached to Object Storage Servers (Section 5.3.5)
• Configuring SFS20 arrays in a minimal system (Section 5.3.6)
• Configuring more than one disk group on an array (Section 5.3.7)
5.3.1 SFS20 storage concepts
Before configuring the storage on the SFS20 arrays, you should be familiar with the following concepts in
relation to SFS20 arrays:
Physical Disk
An SFS20 array can contain up to twelve physical disks. Three disk sizes are available: 160GB,
250GB, and 500GB.
Disk Group
In SFS20 array terminology, a disk group is made up of a set of physical disks.
Logical Drive
A disk group can contain one or more logical drives. From the servers, the logical drive is seen
as a logical unit (LUN). When a LUN is created on an SFS20 array, it is assigned a
16–character WWID that is unique across all RAID arrays from any vendor.
Spare Disks
Each disk group can have zero or more physical disks assigned to act as spare disks, to be used
in the event of a disk failure. HP strongly recommends that at least one spare disk is used for
each disk group.
Host Bus Adapter (HBA)
An HBA is an adapter that is used to connect the server to the storage array. The Smart Array
6404 adapter is the adapter type used for SFS20 storage. Each Smart Array 6404 adapter has
two controllers, and each controller has two ports.