To RAID or Not to RAID?

[r_manic]

We should compile a list of applications where RAID is maximized. Lately I've been seeing people try out RAID not just as an experiment, but as a way to improve system performance. Nothing wrong with that, but if you're limiting your use to "just" gaming, surfing, and work, then I think RAID—with its added complexity and thus more parts that can fail—isn't really worth the trouble.

In fact, I'd only build a RAID array for the following:
■Video capture and editing
■Music capture and editing
■The storage server of a corporate network (or that of a mansion with 10+ computers?)

Anything I missed out?

 

[sub mesa]

This is an old discussion ofcourse.

And i do agree with you, running without RAID has its advantages. You don't need any special drivers or cumbersome installation on RAID volumes. You don't have trouble using NCQ/Hot swap/SMART on the drive since physical disks cannot be directly accessed in RAID-mode and windows drivers. And lastly, you have one less point of failure when not using RAID. And RAIDs do break alot, with the user finding two split arrays or one array with a disk put to offline mode or whatever. If the user performs a wrong/bad operation in an attempt to fix the issue, this may lead to total data loss.

So RAID is not without risks. But i would argue its performance potential is very real. I tested this extensively under BSD and Linux, especially Random I/O performance or IOps is something that can be raised with striping RAID, while normally this could only be speed up by using faster spinning disks (10k, 15k rpm).

What people actually need, is a next-generation filesystem that has internal RAID to use multiple disks in both performance and redundancy in a flexible version. That filesystem already exists today, and it goes by the name ZFS.

ZFS is essentially a filesystem integrating a RAID-engine, backup-system, data integrity control via checksums and an intelligent alternative to journaling; the ZFS Intent Log (ZIL). NTFS is horribly obsolete by comparison, and Microsoft has killed its successor WinFS. So basically Windows is standing still for 10 years at least, while the competition is evolving and innovating.

Its a pity few people (can) use ZFS at this moment. For its great and it changes much about the properties of the RAID levels that you've been taught traditionally. ZFS snapshots would also allow it as a backup, so virusses/accidental deletions won't affect this "history" of the filesystem. By far the most exciting feature i think is checksumming data *and* metadata. This way you will never have corruption again; because when it happens it will be corrected automatically with redundant data and reported to you in the status window. Simple but effective.