I am looking into replacing the single 20gb drive already in my server with a RAID array of some sort. It is a 1U system that normally supports 2 hard drives but can be made to support 3 if I remove the CD-ROM. There are some things that factor into what I should buy: price, performance, and space.
The Raptors seem to provide extreme performance, but only in single-user (even with the 73gb model, I can't find any RAID cards that support TCQ) and are extremely expensive - I would be spending $750 just on the hard drives in a RAID 5 array of them. I can find hard drives that fit more for much less, but the thing is, wouldn't a RAID 5 array of just three hard drives, regardless of the drive, be slower than a single drive?
I also previously considered using RAID 1 for two drives, and purchasing a third drive that was two times the size for backups and the like. At 50% space efficency and slightly slower speeds than a single drive (at least with the 3ware cards) it also appears to not be worth it, except for the ability to restore from a backup in case I accidently delete files.
What I want is something that would work well for light to moderate Web serving and development work, with the available storage space around 100-200GB or so after RAID overhead is considered. If anyone has any specific recommendations, please let me know.
Our solution was to run RAID 1 Mirroring on all servers including mail, dns, web. Now that we run multiable web servers we've also installed a Storage server running RAID 5. Each of the web servers reference the SAN for their content.
It makes it very nice when your looking to do off-site backups. We can just push a relicate of the SAN daily.
Now if a server has problems we can first try and pull the bad drive and get running quickly. Worst case everything is on the master storage server and we can rebuild a new box and mount drives with content.