Desktop RAID is a bad idea

Desktop RAID is a bad idea

Summary: Jon Bach, who runs Puget Custom Computers in Seattle, explains Why RAID is (usually) a Terrible Idea in his blog.Breaks way more often than disks doJon notes that for some reason many of his customers come to him convinced that they need RAID on their home or professional workstations, and he tries to talk them out of it, often with no success.

TOPICS: Hardware

Jon Bach, who runs Puget Custom Computers in Seattle, explains Why RAID is (usually) a Terrible Idea in his blog.

Breaks way more often than disks do Jon notes that for some reason many of his customers come to him convinced that they need RAID on their home or professional workstations, and he tries to talk them out of it, often with no success. I imagine the conversation goes like this:

CUSTOMER: I want to spend hundreds of dollars on RAID.

JON: Well, we build and service hundreds of computers each year and we don't recommend it.

CUSTOMER: Are you a communist? I want RAID. I want to spend the money. I want the hassle. I want the false sense of security. Give me RAID!

JON: Just to prove I'm a capitalist running dog I'll take your money. But I still don't recommend RAID.

CUSTOMER: Fine. Since we're on the subject, what is RAID?

OK, so why is a non-communist against RAID? Maybe because he's part of the reality-based world. As he notes in his post:

. . . I estimate that anywhere from 25% to 30% of our customers with RAID will call us at some point in the first year to report a degraded RAID array or problem directly resulting from their RAID configuration. Granted, a failed RAID1 array does not mean data loss, but it certainly means a long, frustrating hassle.

His judgement is that most customers are happier with regular backups and have way fewer problems. I'd amend that to better off with an automated offsite backup service like Carbonite or Mozy which are both set and forget.

What RAID doesn't protect you from Jon also notes that backups offer protection that RAID doesn't. Specifically, RAID can't help you with:

  1. Accidental deletion or user error
  2. Viruses or malware
  3. Theft or catastrophic damage
  4. Data corruption due to other failed hardware or power loss

Where will Jon recommend RAID? For a desktop machine he allows that striping (RAID 0) may make sense if you know you are I/O bound in things like video editing. He also recommends that if you do go the RAID route, buy a quality RAID controller. He's found that Windows-based RAID software is prone to problems.

Jon isn't talking about server RAID But I will. If smart engineers did a clean-sheet storage design today, they wouldn't come up with today's RAID systems. That, however, is a topic for another time.

Comments welcome. If I can get an account on ZDnet, I'll even try to reply.

Topic: Hardware

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  • RAID is a bad idea?

    It's facinating that you should come up just as I was planning a RAID setup myself. I have setup a 320Gb outside drive on my little Dell E310 and formatted it NTFS. Then I backed up my entire system to it and scheduled automatic daily backups to it. My plan was to set a couple of matched 320 Gb drives into the computer, set them up RAID 0, reload Windows and run a system restore off the outside drive. Do your comments hold for a system that is regularly backed up conventionally?
    • i'd stick with your system

      as above in the post, your solution now prevents against viruses, user error, and other things that a mirrored raid setup doesn't. you're more secure with regular backups.
      Valis Keogh
      • I'd stick...

        Thanks! You've saved me about $150.00 or so. Would using "system restore" from an outside drive work if I were just moving up to a bigger drive?
    • Re: RAID is a bad idea?

      Read the linked story -- the most important question is "What do you need RAID for?" or "Are your typical applications limited by the disk throughoutput only (because that's the only measure which will be affected by RAID0)?".
      • one more

        plus, specifically both articles (parent and the linked one) warn against software RAID on Windows.
      • RE: Desktop RAID is a bad idea

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  • RULE OF THUMB - dont know what it is, dont need it.

    the rule i always use, and it hasn't failed yet:

    if you do not know anything about raid you dont need it.

    positively foolproof. if you dont know what it is, chances are you dont need it. if you're checking your email and playing a few games, please dont bother. if you're video editing, dealing with multigig files, storing terabytes of data, then you do need it, but if you're doing that you already know about raid in the first place.

    Valis Keogh
  • I turned my computer on this morning...

    I turned my computer on this morning and I had the degraded raid message. this sucks
    • Degraded RAID messages happen

      because of a bad controller, bad hard drive, viruses or no UPS.

      Any one of which can cause a cratered Windows install. At least you have a drive to fall back on.
    • Think how much more it would suck if...

      Think how much more it would suck if you didn't back-up your data. Unless you're using RAID-0 (in which case it's your own fault if you put critical data on RAID-0 w/o backing-up that data...), you have a second chance that you wouldn't get if you had only one hard drive and no RAID.

      So long as you realize RAID's designed to save your data in some cases but _not_ designed to save your data in all cases (e.g. a good filesystem is meant to protect against many software errors, learn how to use filesystems, not only RAID... Use them _both_, together.), then RAID is your friend. It's been my friend and save me from hardware failures many a time. :-)
      Reality Incoming
  • I run mirrored drives on my desktop.

    There is absolutely nothing negative I can say about it. Hard drives are cheap and restoring a cratered Windows machine is not. I'm sure he doesn't recommend RAID because he can charge a bundle to fix a cratered Windows computer.

    I have 2 80GB drives. That cost me an extra $45. Data is the only thing I backup so I can keep it off premise. If I have a drive crash, it costs me nothing to keep going. I buy another hard drive and install it. The raid is rebuilt the next boot and I have suffered 20 minutes down time instead of days.

    Any IT person talking bad about mirroring just wants to charge you a bundle when your system crashes.
    • By the way,

      make sure the RAID is hardware based. I agree that software based RAID's can be a nightmare.

      A good motherboard will have hardware based. Cheap motherboards are usually software based.
    • mirrored drives on desktop

      Sounds to me like you'd be right on target. After all... I've been told that RAID stands for [Redundant Array of [Inexpensive] Drives]. Thanks for your help!
    • I've done it both ways - I'd NEVER be without RAID 0 again...

      I've had numerous PCs and done computer support a very long time (since Windows version 1.03b). I have had several hard drives lasts well over 5 years, and I have had drives fail in warranty and some just out of warranty. I have seen drives of a particular model that fail at a very high percentage in the first year of use.

      After the headache of re-installing Windows and all my apps and restoring my files from backups after a hard drive failure, I determined never to be without hardware RAID 1 (mirror). There is no way my time is worth less than the cost of a 2nd hard drive.

      Not long after deciding to go with mirrored RAID, I had another hard drive fail. I knew about it this time not because my PC suddenly froze as before, but because a notification popped up. At the time, I was deep in a project with a crucial deadline hours away. If I did not have RAID, I would have been sunk! Instead, replacing the drive cost me $10 (for shipping) and less than 30 minutes of my time (the time to request warranty replacement, and take the failed drive to UPS for shipping).

      I will NEVER be without RAID 0 again!
      • Oops, I mean RAID 1

        Sorry, I get confused between 0 and 1...

        In the above post I meant RAID 1 - the mirrored configuration, not striped.
  • RAID Good

    I have been running mirrored RAID for about 5 years with no problems until recently when one HDD went south I replaced this and the array rebuilt. On advice from an experienced IT guy I replaced the second drive as well, as he pointed out that the drive that didn't fail was the same age as the one that did. I also have a removable third drive that I use to regularly back up my data.
    • Old mirroring problem.

      If you gou out and purchase 2 identical drives at one time and place them both in the same system environment guess when they will fail? This always has been and alway will be a problem with mirroring. Your replacing the second drive set you up for this. I'd have waited a month or so before replacing the second one.
      • A month?

        I don't think waiting just a month before replacing the second drive in a mirror will
        get you any advantage, if you mean a newer drive will fail later. A month's less use
        on the second drive won't make any real difference--two identical drives put into
        identical use at the same time doesn't mean they're likely to both fail around the
        same time--they're not like clocks. And an extra month in terms of what's in the
        store's inventory isn't going to make any difference.
        John Sawyer
  • Raid arrays

    Has anyone ever calculated the odds of two identical drives, installed at the same time in a raid 1 system both failing at almost the same time? I think the odds are extremely remote. Consider that some drives have 1.2 million hours MTBF and can fail anywhere from 0 hours to way beyond 1.2 million hours. Now that would be a coincidence!
    • Use a separate controller

      Just make sure they have separate controllers or the odds will increase...