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RAID Aid
May 24, 2010 1:21 PM   Subscribe

I need a new Mac. Please help me understand the RAID Card option, and why I should or should not include it with my purchase.

Almost all of my work involves Adobe Illustrator, Photoshop, and InDesign, in that order. Here's the configuration I'm considering:

Mac Pro
• Two 2.26GHz Quad-Core Intel Xeon
• 12GB RAM (6x2GB)
• Mac Pro RAID Card
• HD 1: 640GB 7200-rpm Serial ATA 3Gb/s
• HD 2: 640GB 7200-rpm Serial ATA 3Gb/s
• NVIDIA GeForce GT 120 512MB (for Apple 30" display)
• Two 18x SuperDrives

Please explain to me why I need--or don't need--the RAID card option, or if I'm overlooking better options and configurations.

And please, no "You should/could get a PC for half that price!" answers. I use a Mac.
posted by mattdidthat to Computers & Internet (14 answers total)
 
This isn't answering your question, but I felt obligated to point it out:

The Mac Pro hasn't been updated in over 400 days and the WWDC (developers' conference) is in two weeks; I would seriously wait at least two weeks before pulling the trigger.
posted by entropicamericana at 1:30 PM on May 24, 2010 [5 favorites]


For two 640GB drives, you would not want the RAID card option.

RAID stands for "Redundant array of inexpensive disks" -- meaning that you can create a grouping of disks where if one (or more, in large arrays) disk fails, your data continues to be accessible. It can also be used to stripe disks without redundancy, but that's generally considered a bad idea in any professional setting. Note that RAID isn't backup, it's a safeguard against disk failure.

With two drives, the only sensible RAID option in a professional setting is to have the disks mirror each other -- also known as RAID level 1 -- so that if one drive fails, the other drive can pick up where things left off. However, if you did want to do this, you really wouldn't need a RAID card -- mirroring two SATA drives in a Mac Pro can be done in disk utility as a function of Mac OS X with a small but insubstantial loss of performance.

There are two primary reasons to put a RAID card in a Mac Pro:

* If you have three or more drives, and wanted to set it up so that data was striped across those drives (to create "one big drive") and also so that if one drive failed, you would be able to continue to work with all of your data.

* If you want to use high-speed, high-reliability server-class SAS drives in place of standard SATA drives.

Neither seems to apply here.
posted by eschatfische at 1:34 PM on May 24, 2010 [1 favorite]


Why do you want to run RAID? If you were doing a bunch of HD video work, you would want RAID 0 or maybe 5. It wouldn't hurt Illustrator/Photoshop work, but it's not necessary.
posted by paulg at 1:36 PM on May 24, 2010


For the work I'm guessing you're doing, you don't need the RAID card.
posted by dbiedny at 1:39 PM on May 24, 2010


You do not need the raid card. There is no need for anything but basic mirroring for what you're doing and RAID5 is both slower and more painful when things go wrong.

Please see

http://ask.metafilter.com/135384/RAID-and-backup-system-for-Mac-Pro#1935025

and get both your mac pro configured well and your backup approach worked out. Backup -- not RAID -- is what you need most.

btw: concur with the people who say the pro is about to be updated, but they are solid, outstanding machines.
posted by rr at 1:40 PM on May 24, 2010


Why do you think you need RAID? RAID is not backup. If you earn a living from this machine you certainly need backup.
posted by epo at 2:16 PM on May 24, 2010


RAID is non-stop. If you earn a living from the machine it is not unreasonable to limit the impact of a failure. But RAID5 is overkill and not needed.
posted by rr at 2:23 PM on May 24, 2010


RAID is about availability, except for the abomination which is RAID 0, which is about performance. These days, you can get the latter with a Flash HD: do you need the former?

Work out how long it will take you to restore from backups (you will have backups, yes?) and how much work you'll lose since your last backup (worst case) then ask whether you'll be relying on this machine sufficiently that a RAID setup makes sense. Consider that RAID only partially protects you from downtime caused by HD failure & cannot protect you from user error, fire, theft or a whole bunch of other risks.

(Note that you *must* have spare drives on hand if you're going to run a RAID, otherwise what's the point?)
posted by pharm at 2:46 PM on May 24, 2010


Get a high-end 27" loaded iMac. Replace it twice as often as you are replacing your towers. Sell the old one after two years -- still covered by applecare. Save 65%.

You shouldn't be buying a tower for graphic design work these days -- leave them for the video editors and biologists.

If you still want to spend some extra cash, add in a third party SSD to the iMac for speedy file loading/photoshop cache.

(and... no, don't buy the raid card for the mac pro, just use software mirroring + offsite backup.)
posted by mmdei at 3:06 PM on May 24, 2010 [1 favorite]


RAID is about availability, except for the abomination which is RAID 0, which is about performance.

This is not universally true. RAID 5 provides substantially better read performance than "naked" drives, and the more drives you add to the stripe set, the better that read performance gets. Write performance, especially on small random writes, does take a hit under RAID5, though. Same goes for RAID 10, which tends to improve read performance almost to the degree that RAID 5 does, without anywhere near the write-performance hit.

RAID 1, though, which is what we're talking about here, is solely an availability measure. Conversely, RAID 0 is solely done for performance reasons.
posted by deadmessenger at 3:47 PM on May 24, 2010


I'd second mmdei. I'd also say that unless you know that you need RAID, you don't need it. If I thought that I needed more contiguous drive space than could fit onto one physical drive mech (which you probably don't), I'd probably get a Drobo.
posted by adamrice at 4:18 PM on May 24, 2010


Speaking as an ex-Apple tech support representative, a RAID card in a Mac Pro does two things:
1. It provides hardware support for RAID striping or mirroring management. This means that the computational load required to manage RAID is borne by the card and not your CPU. Unless you expect to have consistently high CPU usage, you don't need to worry about this (and given your purposes, CPU usage should be low).
2. It costs a lot.

In the 3 years I worked there I never encountered a situation where RAID in a Mac Pro was a worthwhile option. This is not to say it never is, but to give you an idea of how likely you are to need it. I no longer officially speak for Apple, but I am entirely confident that my former colleagues' advice would match what the previous respondents and myself are saying: Save the money, drop the card from your configuration, you don't need it.

Furthermore, although I have no inside information (and even when I did work there, us tech support peons rarely found out what new products were being released before they were up on the public store, unless they required extensive new training), Apple keeps a fairly steady schedule for updating its product lines. A new Mac Pro at the WWDC is a pretty solid bet.
posted by fearnothing at 9:06 AM on May 25, 2010


If the money you save has to go to somewhere, I'll second the backup advice, and throw in advice about the warranty - you might have been planning to get the extra anyway, and fingers crossed for not encountering any need to contact tech support for repairs etc, but having those two precautions in place saved me and the people I was helping while working there more time and from more headaches than I care to enumerate.
posted by fearnothing at 9:22 AM on May 25, 2010


You're spending a lot of money, you shouldn't bother with HDDs if you care about speed. Instead of that, get a 160GB Intel SSD. Use that as your boot drive, it will be magnitudes faster than even a RAID0 of the best hard drives you could buy. Get a large hard drive or two if you want but just use them for extra storage, nothing fancy needed.
posted by floam at 11:50 AM on May 26, 2010


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