HP Smart Array 6400 Series Controllers Support Guide, September 2007

3 Configuring Smart Array 6400 Series Controllers
This chapter details the use of the saconfig command to configure Smart Array 6400 Series
Controllers. This chapter addresses the following topics:
“Planning the RAID Configuration” (page 45)
“The saconfig Configuration CLI” (page 45)
NOTE: Some of the commands and outputs in this chapter differ between HP-UX 11i v3 and
previous versions. In those cases, examples from each HP-UX version are provided, and are
clearly identified. If no HP-UX version is specified, then the command or output is the same for
all HP-UX 11i versions.
Planning the RAID Configuration
If you don’t know how you want to configure RAID on your system, follow these steps before
proceeding to the “The saconfig Configuration CLI” (page 45):
1. Determine the RAID level you want to use for each logical drive. See the RAID Technology
Overview at:
http://docs.hp.com/en/netcom.html#Smart%20Array%20%28RAID%29
2. Draw the physical disk configuration. Consider the following:
• Consider having one or more of your logical drives spread across controller channels.
This protects against a cable disconnection and distributes the I/O load across the
channels.
• Consider using one or more online spare disk drives. Spare drives provide extra
protection if there is a disk failure beyond the fault tolerance protection offered by the
RAID configuration. Spare drive capacity is held in reserve and is not available except
when needed to back up a failed physical drive.
3. Choose a stripe size. In most cases, the default stripe size provides the best performance.
Use a smaller size only if you know your data is always written in smaller blocks. For RAID
0, 1 and 1+0 the default stripe size is 128 KB. For RAID 5 and ADG, the default stripe size is
16 KB.
4. Determine the logical drive configuration. Consider the following:
• Only logical drives can be accessed by HP-UX; physical drives cannot be accessed by
HP-UX. Each logical drive is seen as a very large SCSI disk.
• Do not include physical drives of different capacities in the same logical drive.
• HP-UX sees the Smart Array logical drives as disks, so you can use the Logical Volume
Manager (LVM) to configure them as physical volumes. You can then partition the
drive into separate logical volumes.
The saconfig Configuration CLI
Use the saconfig command to do the following:
• Configure logical drives
• Set RAID levels
• Set the stripe size on a RAID logical drive
• Set up online spare disk drives
• Delete logical drives
• Clear the current configuration
• Specify the percentage of the cache used for read caching
• Auto-fail missing disks at boot time
Planning the RAID Configuration 45