19 July,2011 by Jack Vamvas
As part of the Performance Tuning series – Performance Stack , this section looks at Hadware tuning. The purpose of the series is a general approach to Performance Tuning – independent of database server platform. A large proportion of DBAs support more than one type of database server and a methodology allows them to apply to all platforms.
The “Kill it With Iron” approach to Hardware Tuning is popular as the cost of components decreases. Before upgrading hardware \ changing components gather metrics and justify the expenditure.
A DBA can increase the capacity of these components.
Storage Controller Cache
Fibre Channel Switch Rates
RAID systems – Develop in-depth knowledge of RAID systems . RAID levels overview
RAID level 0 aka disk striping : Good read\write ; No redundancy ; No mirroring
RAID level 1 aka disk mirroring : Mirroring ; No redundancy ; No striping
RAID level 3 : Not suitable for database storage. The parity is a major bottleneck
RAID level 5 : Blocks striped. Parity . Very widely used for database storage
RAID level 6 : Extra parity , makes writes expensive. Database storage suffers.
RAID level 10: Mirroring and Striping. A stripe of mirrors.
The major benefit of a applying a RAID system is improved throughput. Disk IO remains a major bottleneck on DBMS systems.
I’ll mention Solid State Disk (SSD) . The costs have decreased and is increasing used .
Create IO patterns per database server activity type. Use as basis for RAID choices and configurations. Are the requirements of a real-time financial transaction system the same as an overnight ETL process?
The overall benefit must be weighed up against costs. Costs include : storage system , storage system support and engineers.