Originally posted by DeepDish:
Anyway, I no very little about RAIDs, but I think software RAIDs are not as good as hardware RAIDs.
Depends on usage. Software RAIDs use the main system CPU to maintain the RAID, so has the potential to impact server performance.
Whether you'll notice this or not depends largely on server volume and the nature of the disk activity (proportion of reads to writes, large vs. small files, etc.)
So, I want to build my own hardware RAID. Don't they sell hardware RAIDs that are completely independate of the server?
Yes, there's many vendors who do this, from the few hundred gigs up to terabytes. The technology also varies depending on the size of the RAID (number of disks, size, RAID type, etc.). ATA at the low end, through SCSI and up to Fiber Channel
Or do I have to buy a special RAID card for our G4 that I attach a bunch of ATA drives to.
You don't have to get a special card, but you can.
Be aware though that ATA only supports 2 drives per channel. Some hardware cards include 2 channels, meaning you can attach 4 drives, but that's about it. SCSI, on the other hand, can handle 15 devices per channel, and Fiber Channel can handle 56.
Also, ATA-100 can only support drives up to 137GB. You'll need ATA-133, SCSI or Fiber Channel to get larger drives.
Some vendors sell external FireWire devices, but these are typically ATA devices on a FireWire bridge.
If so, what if these drives won't fit in the G4 enclosure, can I make my own external enclosure that connects via a special cable back to the RAID card in the G4?
You can fit 4 (or arguably 5) drives inside the standard G4 tower case. If you need more than this then you HAVE to use an external array.
ATA does not support external devices (due to cable length, shielding, and other issues), so SCSI, Fiber Channel, or FireWire arrays are your only option if you need more than 4 drives. SCSI is the most common technology used for external arrays like this.