To JimnTexas:
Well it really depends on the RAID controller you're using. Usually the card comes with drive array monitoring software that will let you know the status of the drives at all times. If one of the mirrored drives fail, you will be notified. There are controllers that allow you to replace the damaged drive without having to shutdown the system. Otherwise, you have to replace the drive and rebuild the data using the provided monitoring program. The amount of downtime to rebuild a lost mirror isn't that bad. As with everything else, if you want little or no downtime, you'll have to pay more for that...


To Dingy:
Well if you just want to combine more than one hard drive into one, you're probably better off using software RAID. You won't be using any RAID levels, but rather what some people refer to as JBOD (just a bunch of disks) or spanning, to just combine the hard drives.

If you want the performance increase of RAID 0 or a similar level, you'll have to use identical hard drives. It's not required but if you don't you'll just be wasting space. For example, if you use a 25gb and 13.5gb hard drive in RAID 0, the total space will be 27gb (13.5 x 2). That's because it needs two identical storage spaces to stripe correctly. The same is true for mirroring or RAID 1. The total capacity is always going to be the smallest capacity hard drive you have times the number of drives, if you're using RAID 0. That's only if you want to use RAID 0, but if you just want everything as one large hard drive, I'd go with a software RAID solution that does that.

To Ed Gillston:
Well duplexed drives don't really offer much of a performance increse as opposed to RAID 0+1 and RAID 1+0 since it doesn't involve striping. I haven't really seen any benches comparing RAID 10 and 01 though. I'd think the performance would be pretty close. As for stripe size, I've heard some people say that the stripe size should match the cluster size. The theory is that each cluster could fit in one stripe. However, that's never really the case. I'm not really sure how much of a performance increase you'll get. I mean there are a suggestions on how to choose stripe size. I think ir really depends on the applications, transaction types, and file sizes involved etc.

To 4665:
The reason I didn't mention Fibre Channel(FC-AL) is because most people and businesses aren't going to be using it. For those who aren't familiar with what it is, it's basically another interface standard like SCSI but uses fiber optic channels. I mean SCSI and Fibre Channel are not JUST interfaces and there's a lot more to it than that, but I'd rather not go into it here. Fibre Channel allows for a sort of network of storage devices. Devices can be separated like 10 kilometers apart, which is a lot more than the 30 meters that SCSI allows. The transfer rate is also in the Gbits/s. You can imagine how expensive this is... It's not as widely implemented as SCSI but I guess it's good to know that it exists.




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