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RAID slows down?

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Thomas Morter-LaingRAID slows down?
by on Mar 5, 2011 at 2:44:19 pm

Ok, so I recently bought a FireWire 800 Dual drive raid system (I've put the enclosure together, it came in bits from here: http://www.span.com/product_info.php?products_id=8081&source=gbaseuk¤....
There are two internal hard drives, both WD Caviar Green, 500GB. It's connected to my iMac via Fw800 directly, nothing else connected. It's set to a Striped array, Mac OS Journaled. When i have the drive on, it slows down startup noticeably. Occasionally it freezes finder. It also reacts oddly when I start disk utility, sometimes Disk Utility takes a LONG time to start working properly. Once it even said one of the partition slices was failing. When not striped, both drives pass Disk Utility's disk repair without any issue, I dont think anything is particularly wrong with the drives themselves. Does anyone know of ways to test this further/ is it normal activity with a FW80" Raid (never used one, might nutmeg be what to expect and I didn't know).
Basically, any ideas?
Cheers!

:D
Tom Morter-Laing
Freelance Editor
Certified Apple Product Proffessional, 2010
http://www.depictproductions.co.uk

Sony Z5, with Rode NTG2.
iMac 27" intel i7 2.93GHz, 12GB RAM, ATI HD5750 [1GB GDDR5], 2TB Int. SATA with 2TB External HDD; (FW800), with Elgato Turbo H264HD.





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Zane BarkerRe: RAID slows down?
by on Mar 5, 2011 at 3:34:27 pm

[Thomas Morter-Laing] "There are two internal hard drives, both WD Caviar Green, 500GB"

BAD choice in drives.

Those drives are designed to conserve power, so they spin down a LOT, that feature is build into the firmware of the drives so unchecking the put hard drives to sleep when possible box in system preferences wont help. Having two of those together in a raid would give horrible performance because each drive is going to independently try and conserve power. So even though you have raided them to act as one drive, you still have two drives each spinning down at different times in attempts to save power.

**Hindsight is always 1080p**


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Thomas Morter-LaingRe: RAID slows down?
by on Mar 5, 2011 at 5:00:18 pm

Fantastic answer, makes total sense thanks so much! I was looking at replaceing these following your answer, would you suggest the Caviar Black's are any good?

:D
Tom Morter-Laing
Freelance Editor
Certified Apple Product Proffessional, 2010
http://www.depictproductions.co.uk

Sony Z5, with Rode NTG2.
iMac 27" intel i7 2.93GHz, 12GB RAM, ATI HD5750 [1GB GDDR5], 2TB Int. SATA with 2TB External HDD; (FW800), with Elgato Turbo H264HD.





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Zane BarkerRe: RAID slows down?
by on Mar 5, 2011 at 5:03:40 pm

Those should be fine.

**Hindsight is always 1080p**


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Chris GordonRe: RAID slows down?
by on Mar 5, 2011 at 5:43:34 pm

I have a WD Black (WDC WD1001FALS-00E8B0) in one of my internal bays and it works great -- get about 100 MB/sec with a single thread/queue/process writing to the disk. Apple shipped a WD Blue (WDC WD3200AAJS-41VWA1) as the system disk (2008 Mac Pro, MacPro 3,1) and it gets about 50 MB/sec for single process writes. The Black does give you a good boost.


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John DavidsonRe: RAID slows down?
by on Mar 5, 2011 at 10:20:07 pm

Make sure they work with your enclosure. I've switched my preference to 2TB Hitachi Deskstars over Caviar Blacks. Some enclosures don't like the WD Caviar Blacks, but the Deskstars are pretty affordable right now ($115 on Amazon) and I'm really pleased with their performance in my 2 drive NAS system in RAID 1.


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Thomas Morter-LaingRe: RAID slows down?
by on Mar 6, 2011 at 4:51:58 pm

Cheers i think I'll go that way.
Anyone have any idea why it would slow down computer startup though?
Thanks!

:D
Tom Morter-Laing
Freelance Editor
Certified Apple Product Proffessional, 2010
http://www.depictproductions.co.uk

Sony Z5, with Rode NTG2.
iMac 27" intel i7 2.93GHz, 12GB RAM, ATI HD5750 [1GB GDDR5], 2TB Int. SATA with 2TB External HDD; (FW800), with Elgato Turbo H264HD.





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Zane BarkerRe: RAID slows down?
by on Mar 6, 2011 at 6:08:26 pm

[Thomas Morter-Laing] "Anyone have any idea why it would slow down computer startup though?"

Well I believe the Mac OS does a basic check on all hard drives connected when started up. A hard drive that has issues could slow that whole disk check process down.

**Hindsight is always 1080p**


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