HP Surestore Disk Array 12h System Administrator's Guide for HP-UX, MPE, and W - Page 17

HP-UX Managing the HP SureStore E Disk Array 12H on HP-UX Tips for Configuring the Disk Array On HP-UX Tips for Configuring the Disk Array On HP-UX Before installing a new disk array, you should determine what is more important for your operating environment - performance or capacity. This decision will influence how you configure the disk array hardware and LVM. There are several configuration options that impact the performance of the disk array. Table 2 identifies the various configuration options, their impact on disk array performance, and any considerations regarding disk array capacity. NOTE! Overall system performance is a complex issue influenced by many factors. The configuration options described here will increase the potential performance of the disk array. However, the actual performance of the disk array will be determined largely by host demand. AutoRAID technology is particularly suited to I/O-intensive application environments such as OLTP and NFS. It is in these environments that the performance benefits offered by AutoRAID will be fully realized. Configuration Option Number of LUNs per disk array Number of disk arrays per SCSI host adapter Table 2. Configuration Options Impact on Performance and Capacity Performance. Increase the number of LUNs per disk array to improve performance. More LUNs increases the size of the I/O command queue allocated by HP-UX, which increases throughput. The recommended number of LUNs is 4 to 6. Capacity. To allow for future capacity expansion, avoid creating the maximum number of LUNs (8) on the disk array. New capacity is made available through the creation of a new LUN. If the maximum number of LUNs have already been created, it will be necessary to delete and recreate an existing LUN to increase capacity. Performance. Limit the number of disk arrays per host adapter to improve performance. The recommended configuration for maximum performance is: NIO adapter - 3 disk arrays GSC adapter - 8 disk arrays Capacity. If maximum capacity is more important than performance, connect the maximum number of disk arrays to each adapter. 17