RAID 10 for the win.
It doesn't require parity calculations and writing
Should a drive die rebuilding a mirror is faster
Write performance is good (2x) Read performance is better (4x)
Since storage is cheap and a Mac Pro has 4 bays a RAID 10 isn't a
bad idea.
To me, it's a nice balance of performance, redundancy, and affordability. It can be done with a software implementation, so it's only the cost of drives. Which are fairly inexpensive these days.
Nanofrog, that's my issue in these forums as well. But I go farther. I say 10 is also overkill and a half. With 10 you are doubling the number of drives on the off chance one of them breaks and you weren't wise enough to have a backup. That's awfully wasteful in terms of both space and money. RAID level 5 is kinda the same thing IMO. You're paying for not only the card and extra drive itself but also the $200 a year or so it costs in electrical consumption. Not to mention that in both 5 and 10 the extra drives are useless for anything other then one single dedicated purpose. IMO if you're "working" with video or other then level 5 has a place in your planned system but I can't ever see a reason to run 10 unless the person has access to free drives or something. I would probably feel differently if Mac Pro came with 8 or 10 hot-swappable drive bays.
I was just making mention of the potential issues. I'm not the greatest proponent of RAID 0, as my usage
requires redundancy of data and high system availibility. I just don't have the time to spend recovering the data, let alone lose any of it.
That may or may not be applicable to anyone else, and they have to decide for themselves.
I just wanted to at least give the OP the basic knowledge that it might be something to consider.
For home/hobby/.. use, a stripe set and a decent backup system is adequate. An even lower cost alternative than RAID 10 to boost performance, and as it's not used for anything critical, I'll presume the individual does have the time to spare if the array does fail.
Additionally, the individuals skill level may come into play, and this is where 10 may have an advantage. Auto rebuilds.
IMO a RAID 0 really starts to add s noticeable system performance boost at 3 drives. Well for that to be taken advantage of in a RAID 10 you need to run 6 drives.
Not to mention the slight performance hit incurred in RAID 10. RAID 5 also has a performance hit but at least we're only running 4 drives now - better (for Mac Pro) but expensive if it's not paying for itself.
3-4 seems about right to me as well. A decent balance of speed and an acceptable level of failure risk, provided the backup system is in place. Otherwise, it's a disaster waiting to happen.
I like RAID 0 the best by far!!! Especially for general or hobby level use. You can have your 3 or 4 drive RAID for ultra fast rates and also have room for 2 other drives. For general use (and I'm finding even for video) it actually makes the most sense to increase your memory to 12 or 16 GB and then just put EVERYTHING on one RAID 0. Everything means your boot, your apps, your video, your scratches, and your resources - all of it. The access contention that people warn against just never in reality, ever actually happens. If you're on a low 2GB or 4GB, memory system I could see a few cases where an application's cache could occasionally slow things up but with 12 GB, 16 GB, or even 24 / 32 GB this also becomes a "never actually happens" case.
Other graphics/video professionals I've spoken with have had some issues with availability and data loss, and approached me about another method. They're business was affected by the failure, and decided the financial investment made sense for their particular needs. Better backup strategies were discussed as well.
As thier incomes were derived from their computers, it seemed reasonable that other array types would be more appropriate. They had come to the conclusion that it was a justifiable expense.
3 or 4 drive RAID 0 with a backup drive just makes the most sense when the system isn't dedicated to mission critical "work".
Despite the length of the posts, we do seem to think similarly, as I do agree that in non critical work, and the user has the time to spare in case of a disaster, this solution is viable. The low cost is just too hard to ignore.
I was almost convinced to either let the whole RAID idea be, or go with a semi-safe route and set up four 1TB HDs as RAID10. That plus the 1TB I could place in the optical bay would give me 2.7TB in total and I would still have to back up externally. 2.7TB sounds like a lot, but it isn't, really. I would like to have up to 3TB for the next couple of years, but I also want to just use 50% of the HDs (for better performance). I would go with four 1.5TB HDs as RAID10, but there's only the Seagate drive available at the moment and it gets a lot of bad reviews.
Have you considered the WD
WD20EADS?
2 TB, and reviews well (
here,
here). Individually, they aren't the fastest drives on the planet, but in a 4 drive array, you'd be quite pleased I think.
They should handle your capacity issues for awhile. If not, you may be in trouble.
After your comments I would go with this set-up:
- Four 1TB Hitachi Saturn Enterprise HDs as RAID 0 (supposedly the best 1TB HDs)
Partition the drives (scratch disk | OS & apps | work | iTunes media)
and as per your recommendation, put EVERYTHING on the 4TB RAID 0
- One 1TB HD in the optical bay.
Schedule (hourly) incremental back-ups with CCC of critical parts from that 4TB array (OS & apps | work | new iTunes media)
- Several external HDs to back up the 4TB RAID drive entirely
Schedule (daily/weekly) incremental back-ups with CCC
This way I basically would have a very fast 4TB HD to work with (with a higher disk failure risk than a non-RAID disk of course) and a complete backup of the entire thing on external HDs.
The 1TB backup HD in the optical bay would always be up-to-date and bootable. So in case of a problem, I could just restart and keep working right away from the 1TB.
I assume the biggest PITA would be to restore the four-disk RAID array from the external HDs. But that's mainly a matter of copying files all night.
In the fuure, when 2TB drives will as reliable as the current 1TBs I could re-arrange to a "safer" RAID 10 setup if need be ....
At this point, I'll assume you have the time to perform a rebuild should something go wrong. So you're idea would work. I wouldn't even bother partitioning it though, particularly if you can manage to keep each disk at 50% capacity or less.
And you can always change to another array type later if the need arises. Fairly simple to do as well. Hardware can complicate it a bit, primarily due to the interface. It can be intimidating if you don't know what settings to choose.
Just keep in mind, you'd have to make a fresh backup first, as the data will be gone (software or hardware). Each time you initialize a drive, it gets wiped.
