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View Full Version : raid 0 scratch/storage, FW800 as boot disk for mini




blackmtn
Mar 21, 2010, 10:53 PM
I know this should be in the iMac/mini forum, but no one there has responded and most probably don't even know what I'm talking about! So please forgive me this posting it here :)

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I'm looking to replace my current iMac (first gen intel with ati x1600) because it has terrible graphical glitches with Aperture under SL.

The iMac has tons of processor power for my use, but only one internal storage drive. It also has the glossy screen that is too bright for photo print matching and it still seems to have this yellow tint problem.

The Mac Pro would be awesome for my use - lots of power and internal drive bays and I can pick any monitor I want - but it costs a small fortune.

I then stumbled on the Mac Mini Server version and I'm thinking this might be a good choice because of the two internal drives - my initial thought on set up follows:

Use the two 500gb internal drives as a RAID 0 and have two small partitions on each as my Photoshop and PTGui scratch drive. (I've been doing some reading over at http://macperformanceguide.com/Storage-HowToSetupRAID.html.) The larger remaining partitions would be for my Aperture library and misc data (currently at only 120gb). This way I have the fastest portion of each disk dedicated as scratch (when stitching large mosaics I easily exceed my RAM so WILL use lots of disk cache.) As I understand it, having a striped RAID should speed up the 5400 laptop drives quite a bit.

I would then have OS X installed on a FW800 drive on a smaller partition (first on the drive for faster access) and use the remaining for Time Machine backups.

I have a few questions about the viability of this set up however:

1) Is the OS X software raid option reasonable? I want my internal striped raid to be reasonably reliable (i.e. only to fail if the actual hard disk fails) - I thought I read somewhere once that OS X can be a bit flaky for RAID, but I wasn't sure if that was in relation to set up or ongoing use.

2) What would be the (roughly) theoretical speed of a striped RAID using 5400rpm laptop drives? My thought is that it would be faster than the FW800 interface is capable of transporting (~ 55-60 MB/s). The whole point of this is to have a fast scratch disk for stitching/editing my large (~200 megapixel) mosaics - I think I would need something on the order of 16gb RAM to avoid disk caching, but that is stupid expensive in an iMac and the Mac Pro is really expensive already, so I think I am basically stuck with disk caching.

3) Where does OS X go to when it needs disk cache? I can point Photoshop and PTGui manually at the scratch drive I create, but when working in Aperture I will also probably exceed the 4gb RAM that the Mini comes with, so will go into OS X disk cache.

4) How fast will FW800 be as a boot drive? Will it seem much slower than my old iMac with an internal 7200 rpm drive? (Which, as full as it is, seems capped at about 50 MB/s.)

5) Will I be able to run Bootcamp from an external drive? I have also heard that it doesn't let you use more than the system + bootcamp partition on the same drive, so if that's the case, I guess I'll need a 2nd external drive for Time Machine.

6) Is the 9400M better than the x1600 as a video card? While PS and PTGui don't use the GPU at all, Aperture supposedly offloads as much as it can to it, and I would like Aperture to be snappier on my new machine than my current one.

I've done some tests the last few days on the programs I use the most often on my current computer and have noticed that Aperture is processor bound on regular RAW files but disk cache bound on large files (I only have 2gb RAM currently); Photoshop is the same; while PTGui is almost always disk cache bound, so until I get rid of the disk cache bottleneck I don't think that having an i7 in an iMac or similar processor will be much better for me than the 2.53ghz processor that comes with the Mini.

In terms of the Server version of OS X that this Mini comes with, I mainly intend to use it as a print/file server for home use and to serve up my own webpages. I have also toyed with the idea of serving some webpages for some small local companies that I have already built simple websites for (ie charge them). I do want to get into some server side languages (eg PHP) for my own websites, so that would be the attraction of serving my own sites. Is Server overkill for this? Can I already serve multiple webpages with a regular version of OS X?

Anyways, any help on the above questions would be fantastic! Thanks