HP XC System Software Installation Guide Version 3.2

You have the option to enable software RAID-0 (striping) or software RAID-1 (mirroring) on
client nodes. RAID is an acronym for redundant array of inexpensive (or independent) disks. RAID
is a way of combining multiple disks into a single entity to improve performance or reliability
or both.
Software RAID-0 (striping) enables client nodes that have more than one storage disk to split
data evenly across the disks. Striping is typically used to increase performance. However, because
there is no parity information for redundancy, reliability is reduced. A single disk failure affects
both disks. Software RAID-0 is not supported on the head node.
When a client node is imaged with software RAID-0 support, the /boot partition is mirrored
and swap partitions on each disk are not striped or mirrored. Linux automatically stripes across
swap partitions when the swap partitions are on separate disks.
Software RAID-1 enables client nodes that have more than one storage disk to increase reliability
by maintaining a redundant (mirrored) disk copy. When a node is imaged with RAID-1 support,
the entire disk is mirrored. If a disk fails, nodes can continue to run using the other disk.
To enable software RAID-1 on a client node, the following criteria apply:
• The client node must have two or more disks; only two disks are used in the RAID set.
• Disks must be the same size.
Follow this procedure to configure software RAID-0 or RAID-1 on one or more client nodes:
1. Use the text editor of your choice to edit the following configuration file on the head node:
/etc/systemimager/systemimager.conf
2. Add the following line or lines to the bottom of the file to enable software RAID-0 or RAID-1.
Replace node_prefix[n-n] with the node prefix and the range of nodes on which you
want to enable software RAID (for example n[1-4,7,9]). You must include a space before and
after the equal sign (=).
SOFTWARE_RAID0_NODES = node_prefix[n-n]
SOFTWARE_RAID1_NODES = node_prefix[n-n]
3. Save the changes to the file and exit the text editor.
3.7.11 Create Local User Accounts
This task is optional. If you intend to create local user accounts on the HP XC system rather than
manage user accounts through another user authentication method (such as NIS or LDAP), use
the Linux adduser command to create local user accounts on the system now, before the system
is configured.
See the HP XC System Software Administration Guide if you need more information about creating
local user accounts.
Special Considerations for Nagios and LSF
During the system configuration phase, the cluster_config command attempts to create a
nagios and an lsfadmin account for use by Nagios and LSF, respectively.
To use existing nagios and lsfadmin user accounts from a site wide NIS system (or some
other external user authentication system), you must manually create local XC accounts that
mirror the site wide accounts (with matching user identification (UID) and group identification
(GID) values). In that way, the cluster_config command uses these local accounts to properly
configure Nagios and LSF with the right file permissions, access, and so on.
3.7.12 Override Default User and Group Account IDs
This task is optional. Perform this task only if the default user and group IDs are not suitable for
your environment.
82 Configuring and Imaging the System