I have 3 drives in my system, one 1,5tb one and 2 1tb F1 drives. I've been thinking about making a mirrored raid out of the 1TB f1's. I was wondering though, would I see the greatest performance increase by using the raid as my system drive (the OS, apps, etc), or the drive where I keep my Final Cut scratch, etc?
Got a tip for us?
Let us know
Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
Should I RAID the "cache" drive or the system drive?
- Thread starter DaSal
- Start date
- Sort by reaction score
Ok... So... If I'm doing it for video editing (Final Cut, After Effects), I'd get the best performance by storing my video on the mirrors, as the applications read it from the drive?
Potentially, but only if you are reading a bunch of data. If you are also writing a bunch of data, it may take just as long. When the discussion turns to high-performance RAID arrays, you really should look at hardware controllers that support RAID 10/01. Software mirrors really only assist in recovering from hardware failures. They do little for performance (in fact may reduce performance).
I see. So considdering I would be using a software raid it's probably better to just not use a RAID at all, and backup manually when needed?
Whoa whoa whoa.
Mirroring does not increase performance, it only protects against drive failure. In fact, unless you have a very good RAID card, mirroring will cause a slight decrease in performance.
Now stripping (RAID 0) will increase performance and it would probably be best to do this on your scratch/working drive. But make sure you BACK UP your data as RAID 0 doubles the chance of loosing your data to drive failure.
Mirroring does not increase performance, it only protects against drive failure. In fact, unless you have a very good RAID card, mirroring will cause a slight decrease in performance.
Now stripping (RAID 0) will increase performance and it would probably be best to do this on your scratch/working drive. But make sure you BACK UP your data as RAID 0 doubles the chance of loosing your data to drive failure.
No, mirroring can also help in read performance. I'm not sure how OS X does it, but if you are reading data from a mirrored array, the controller can use both drives to read that data. This is especially helpful where multiple files are being read at once.
I'm not sure how it could decrease read performance in any way. There's no parity calculated on RAID 1, and even if you don't use the second drive, you are still reading from the first.
And don't forget - a mirrored RAID is NOT a backup. It helps protect from hardware failure, but its not a backup - delete something by accident or get a corrupted file, its gone from BOTH drives.
Right... I see. I'm confused, what do people usually do? Make a RAID 0 and then mirror that? (4 hd's?) Is that possible? Not that it's applicable to me anyway, just curious. I assume one can't raid partitions on different drives? In that case I could make a 1tb raid with 2x500gb partitions and then a 1tb mirror with the other 2x500gb partitions. I don't think this is possible though, is it?