Heh. Funny.

-systemsboy

Brian needs to work at a place where he can feel more appreciated. It seems obvious that he has a great need to share his wisdom. Also, 10 != 2.

-systemsboy

There was definitely a performance increase having 2 mirrored drives on my system (mac pro/5GB ram/etc)

Sustained reads jumped from about 60mb/sec to 97mb/sec and sustained writes are about the same when copying huge files.

The array also ate through heavy digital audio data and large video files during sessions.  A substantial performance increase compared to a single drive.

Also when I used to use PC for audio, at the time I had a Promise Ultra 133 RAID card with 2 x 40gb (hehe huge!) mirrored – and read performance was greatly higher than a single drive.

Just my .02,

Neil

The article deals specifically with Apple’s software RAID capabilities. That’s why the title says, “Apple Software RAID Tests,” and why that phrase or variations on it are sprinkled throughout the article. It is not meant to be a comprehensive treatment of RAID technology. It’s only meant as a description of the capabilities and limitations of Apple’s included RAID utilities. “Concatenated RAID” is the language used by Apple in said utilities, so it’s what I used. If I’d said something else, the article wouldn’t make sense.

Apple’s RAID software may be crap. I suppose it depends on what you need to do. For many I’m sure it’s more than adequate. For me it’s simply interesting, in an academic way. But not so interesting that I feel like appending my article.

Thanks for the detailed comment.

-systemsboy

You say “Concatenated RAID”. There is no such thing. It has nothing to do with RAID. There is RAID 0, 1, 2, 3, 4, 5 and that’s it. Other things are either made up, mistakes, BS marketing, or stacking (mirroring striped volumes, for example).

I was doing concatenated drives with a normal driver back in… 1993? Mirror Technologies driver supported this. Please make a note of correction.

Also, and this may be of more direct interest to you, when you write “First of all, software RAIDs cannot be partitioned, which I actually didn’t realize, though it does make sense.” you are again wrong.

The problem is that Apple’s RAID software, although priced right, is crap. To make RAID partitions you have to FIRST partition EACH drive you want to put into the array the size you want it to be.

For instance, if you want a 30GB RAID 1 (mirrored) startup partition, a 40 GB RAID 0 (striped) partition, and the rest of the drive as a normal partition, you have to do this:
Partition your first drive into 3 parts: a 30GB, a 40GB, and the rest as normal. Again, due to the crappy nature of Apple’s RAID software, you can’t make the 30 and 40 free space to save time.

Then Partition the 2nd drive the same way (note, it can be bigger or smaller than the first drive, and no, for striping it doesn’t much matter that the drives don’t match).

NOW make your RAID 1 partition dragging the 30GB partitions over. Ah ha!. The 40 GB striped is easy at that point. Don’t forget the rebuild automatically and why that isn’t the default I’d like to know.

Let me tell you, this really makes a sysadmin appreciate Veritas’s disk management software.

Anyway, I was able to boot my PPC Mac mini from a similar arrangement (I mirrored the entire internal drive against a larger firewire drive) and it worked just fine.

I didn’t check the rest of what you wrote, but hope you can correct or notate the original post and hope the partitioning bit helps. If you don’t like the way Apple’s RAID software works, you can get SoftRAID, which is much better.