We are looking at purchasing an HP EVA4000 for SQL and Exchange servers. HP highly recommends their Fibre Channel (FC) drives, but they've got new Fibre Attached Technology Adapted (FATA) drives that we are considering. We know an FC drive will cost roughly two times as much as a FATA drive. So, we could have twice as many FATA spindles working for the same price. Can you think of any reason to use the FC over FATA?
If you can afford the FC disk drives and your applications can benefit from the lower latency, you could go that route. However, performance aside and assuming that your environment and applications will be fine today and in the future with the FATA disk drives, that is a viable option. FATA is essentially FC attached disk drive with dual porting similar to a regular FC disk drive. The big difference is in the price and lower performance -- putting FATA on par as an alterative to Serial Advanced Technology Attachment (SATA) disk drives offered by other vendors. HP and other vendors including EMC (DMX and new CLARiiON CX3) and Xiotech also utilize FATA type disk drives under different marketing names in addition, or instead of, SATA disk drives.
For update and write-intensive applications go with RAID-1 vs. RAID-5, granted you will consume more raw capacity, however you will still have plenty of capacity from the looks of it. So, assuming that performance will be OK, and that HP agrees to support your needs and provide remedies such as substituting faster disk drives if necessary, using FATA gives you the benefit of saving on power, cooling and enclosure rack space -- not to mention some additional capacity.
In general, the more you can spread data across multiple disk drive heads is good. However again, look at and assess your applications performance requirements and have the consensus of the supporting vendor before using the larger capacity, slower disk drives. Look beyond cost or savings of the FATA vs. FC disk drives, considering the performance and configuration to support your applications needs including the longer disk drive rebuild time for the larger capacity disk drives now and in the future.
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This was first published in June 2006