Online Data SAN Configuration
When configuring a SAN for online services such as OLTP or OLAP databases there are so many different options to choose from.
Many SAN servers are configured with a large amount of Cache resulting in acceptable performance regardless of disk configuration. On these larger SANs you may find a single RAID 5 or RAID 10 physical configuration is adequate for all luns.
For the smaller SAN servers, you will probably need to fragment your disks more for the actual purpose they are supporting because the physical disk access is more significant in the actual performance. In this situation, get as many drives as you can in order to increase performance through RAID configurations.
Sometimes a SAN may be configured with Solid State Disk as well as physical hard disks. The SSD volumes allow you to place data requiring high speed access. This is great storage for Data Marts, Cubes, and other data that is less dynamic.
Some have chosen to use SSD for things like tempdb which greatly reduces the life. As costs are coming down for SSD, and the life cycle of SSD continues to improve, using SSD for highly volatile data is becoming acceptable, with plans for a short lifecycle of the drive. Some installations will even create a mirror volume consisting of two SSD devices, allowing them to be replaced without interruption. This is a configuration Amazon has published in its database software as a service offering.
I expect this summary of ideas will not provide you guidance as you look to configure your SAN. My intention is to provide some high level ideas allowing you to communicate effectively and ask questions relevant to your needs.
I expect that is enough about SANs for now. Don’t hesitate to drop me a note if you have other comments from which you feel our readers will benefit. Drop me a note at btaylor@sswug.org with your comments.
Cheers,
Ben
$$SWYNK$$
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