Follow these guidelines when selecting volume layouts:

• Put the database log files on a file system created on a striped and mirrored (RAID-0+1) volume separate from the index or data tablespaces. Stripe multiple devices to create larger volumes if needed. Use mirroring to improve reliability. Do not use VxVM RAID-5 for redo logs.

• When normal system availability is acceptable, put the tablespaces on file systems created on striped volumes for most OLTP workloads.

• Create striped volumes across at least four disks. Try to stripe across disk controllers. For sequential scans, ensure that the NUM_IOSERVERS and DB2_PARALLEL_IO settings are tuned to match the number of disk devices used in the stripe.

• For most workloads, use the default 64 K stripe-unit size for striped volumes and 16 K for RAID-5 volumes.

• When system availability is critical, use mirroring for most write-intensive OLTP workloads. Turn on Dirty Region Logging (DRL) to allow fast volume resynchronization in the event of a system crash.

• When system availability is critical, use RAID-5 for read-intensive OLTP workloads to improve database performance and availability. Use RAID-5 logs to allow fast volume resynchronization in the event of a system crash.

• For most decision support system (DSS) workloads, where sequential scans are common, experiment with different striping strategies and stripe-unit sizes. Put the most frequently accessed tables or tables that are accessed together on separate striped volumes to improve the bandwidth of data transfer.