SAS vs FC HDD inside fiber channel storage system

[Taoufik Grira]

Hi,

my company is about to acquire a new midrange FC disk array that will be integrated to a transactional DB envioronment with high I/O load. We have got different offers:
- Full FC disk array with 300G/15krpm FC HDD.
- FC disk array (SAN connection) with 300G/15krpm SAS HDD.

I need to decide whether a FC disk array with 15krpm SAS disks is enough reliable in such environment and so list it as candidate;

Can you please give some advise, and point me to a link detailing the perfs and architecture differences between SAS and FC HDD in terms of internal interconnection to the FC storage system.

Thanks and Regards,
Taoufik

[Torsten.]

What array models do we talk about?

[Jan Soska]

hello,
I noticed some rumors that 6Gb SAS is fast enough to be a real competition to FC connected disks....

Jan

[Taoufik Grira]

Hello,

Thanks for your answers; The disk array is Hitachi AMS2300; But I would like to have a comparision between both architecture and configuration in general whatever the storage system.

Thanks,
Taoufik

[Víctor Cespón]

For high I/O load you're not limited by the cable speed. You'll reach the maximum number of I/O per disk much sooner. 4 Gb/s are 400 MB/s.

In a typical database environment, 100 15K disks in RAID 5 can give you 7.200 IOPs. If each IO is 4 K, you have only 28 MB/s.