EMC CLARiiON MetaLUN Performance Tuning Best Practices
Meta lun in the same raid group will decrease the LUN performance.
Some best practice rules are below mentioned
- Do use the correct RAID level for the pattern of I/O
- Do not have more than one component LUN from any particular RAID group within the same metaLUN stripe. This would cause linked contention.
- Do use drives of the same capacity and rotational speed in all the RAID groups in the metaLUN. The RAID groups should also contain the same number of drives.
- Do not include the vault drives in the metaLUN.
- Do use sets of RAID groups that only contain metaLUNs that are all striped in the same way, if possible. Having standard LUNs in the same RAID group as metaLUN components will lead to some parts of a metaLUN having uneven response times across the metaLUN. The order in which the component LUNs are added can be changed to evenly distribute the file system load (for example, RAID Group 1,2,3, and 4; then RAID Group 4,1,2, and 3, etc.). The dedicated RAID group sets for metaLUNs are sometimes referred to as CLARiiON HyperGroups.
- Do not concatenate stripes with large numbers of drives to components with much fewer drives. This will lead to performance varying dramatically in different parts of the same metaLUN.
- Do name the component LUNs in such a way as they are easy to identify (article emc103765). Numbering the components in a logical order helps to choose the correct RAID group and default SP owner (article emc98038) although the component LUNs will be renumbered when the metaLUN is created. The metaLUN will have its own default owner, but choosing the same default owner as all the components avoids the components being reported as being trespassed in some tools.