General Performance Guidelines

When you design your storage configuration, consider the following performance guidelines:

• Striping generally has the best performance, but it offers no data redundancy. For write-intensive applications, RAID 1 volumes generally have better performance than RAID 5 volumes.

• RAID 1 and RAID 5 volumes both increase data availability, but they both generally have lower performance, especially for write operations. Mirroring does improve random read performance.

• RAID 5 volumes have a lower hardware cost than RAID 1 volumes, while RAID 0 volumes have no additional hardware cost.

• Identify the most frequently accessed data, and increase access bandwidth to that data with mirroring or striping.

• Both stripes and RAID 5 volumes distribute data across multiple disk drives and help balance the I/O load.

• Use available performance monitoring capabilities and generic tools such as the iostat command to identify the most frequently accessed data. Once identified, the access bandwidth to this data can be increased using striping, RAID 1 volumes or RAID 5 volumes.

• The performance of soft partitions can degrade when the soft partition size is changed multiple times.

• RAID 5 volume performance is lower than stripe performance for write operations, because the RAID 5 volume requires multiple I/O operations to calculate and store the parity.

• For raw random I/O reads, the stripe and the RAID 5 volume are comparable. Both the stripe and RAID 5 volume split the data across multiple disks, and the RAID 5 volume parity calculations aren't a factor in reads except after a slice failure.

• For raw random I/O writes, the stripe is superior to RAID 5 volumes.