Ideal RAID configuration for a media server

TimJar
TimJar used Ask the Experts™
on
Hello,
I am looking for the fastest sequential write speeds for large files (5 to 20 TB) with some redundancy. I am using Adaptec 31605 card with BBU. I have 12 2TB SATA drives to work with. I keep a backup on another server. These are my questions:
Should I use RAID 5, 50, or 6? (RAID 10 doesn't geive me enough storage for expansion)
Should I use 1024kb stripe size?
Will write cache help me at all?
If RAID 50 is best, what configuration will have fastest write speed? 3x4, 4x3, or 2x6

Thanks,
Tim
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This site is a good reference point:
http://www.wmarow.com/strcalc/
Top Expert 2014
Commented:
2GB SATAs aren't generally enterprise disks so the highest level of protection is best, RAID 6. You may still suffer from disks dropping out of the array when they encounter an error, desktop drives go into deep recovery mode trying to get the data if a soft read error occurs which can take up to 30 seconds in which time the controller's given up on it and thrown it out of the array as faulty.

Use a large strip size since it's sequential data, the RAID level shouldn't hurt write speed too much as you've got BBU and because sequential writes generally let it do a full width stripe write so it doesn't have to bother to read parity and xor.

Author

Commented:
Thank you both. The RAID calculator was very helpful as well as the info on stripe size and Write cache

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