Installation guide

Section 2.4:Steps for Setting Up and Connecting the Cluster Hardware 45
Multi-initiator SCSI configurations are not supported due to the difficulty in obtaining proper bus
termination.
• The Linux device name for each shared storage device must be the same on each cluster system.
For example, a device named /dev/sdc on one cluster system must be named /dev/sdc on
the other cluster system. Using identical hardware for both cluster systems usually ensures that
these devices will be named the same.
• A disk partition can be used by only one cluster service.
• Do not include any file systems used in a cluster service in the cluster system’s local /etc/fstab
files, because the cluster software must control the mounting and unmounting of service file sys-
tems.
• For optimal performance, use a 4 KB block size when creating shared file systems. Note that some
of the mkfs file system build utilities have a default 1 KB block size, which can cause long fsck
times.
The following list details the parallel SCSI requirements, and must be adhered to if employed in a
cluster environment:
• SCSI buses must be terminated at each end, and must adhere to length and hot plugging restrictions.
• Devices (disks, host bus adapters, and RAID controllers) on a SCSI bus must have a unique SCSI
identification number.
See Section A.2, SCSI Bus Configuration Requirements for more information.
In addition, it is strongly recommended to connect the storage enclosure to redundant UPS systems for
a highly-available source of power. See Section 2.4.3, Configuring UPS Systems for more information.
See Setting Up a Single-Initiator SCSI Bus in Section 2.4.4 and Setting Up a Fibre Channel Intercon-
nect in Section 2.4.4 for more information about configuring shared storage.
After setting up the shared disk storage hardware, partition the disks and then either create file systems
or raw devices on the partitions. Two raw devices must be created for the primary and the backup
quorum partitions. See Configuring Quorum Partitions in Section 2.4.4, Partitioning Disks in Section
2.4.4, Creating Raw Devices in Section 2.4.4, and Creating File Systems in Section 2.4.4 for more
information.
Setting Up a Single-Initiator SCSI Bus
A single-initiator SCSI bus has only one cluster system connected to it, and provides host isolation and
better performance than a multi-initiator bus. Single-initiator buses ensure that each cluster system is
protected from disruptions due to the workload, initialization, or repair of the other cluster system.
When using a single or dual-controller RAID array that has multiple host ports and provides simulta-
neous access to all the shared logical units from the host ports on the storage enclosure, the setup of