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Experiences w/ Software RAID 5 Under Linux?

Posted by Cliff on from the how-well-has-it-worked-for-you dept.

MagnusDredd asks: "I am trying to build a large home drive array on the cheap. I have 8 Maxtor 250G Hard Drives that I got at Fry's Electronics for $120 apiece. I have an old 500Mhz machine that I can re-purpose to sit in the corner and serve files. I plan on running Slackware on the machine, there will be no X11, or much other than SMB, NFS, etc. I have worked with hardware arrays, but have no experience with software RAIDs. Since I am about to trust a bunch of files to this array (not only mine but I'm storing files for friends as well), I am concerned with reliability. How stable is the current RAID 5 support in Linux? How hard is it to rebuild an array? How well does the hot spare work? Will it rebuild using the spare automatically if it detects a drive has failed?"

2 of 541 comments (clear)

  1. Re:Stick with hardware RAID by Anonymous Coward · · Score: 5, Insightful

    Actually, a big disadvantage to hardware RAID is what happens if your controller fails.

    Consider--your ATA RAID controller dies three years down the road. What if the manufacturer no longer makes it?

    Suddenly, you've got nearly 2 TB of data that is completely unreadable by normal controllers, and you can't replace the broken one! Oops!

    Software RAID under Linux provides a distinct advantage, because it will always work with regular off-the-shelf hardware. A dead ATA controller can be replaced with any other ATA controller, or the drives can be taken out entirely and put in ANY other computer.

  2. Software RAID is probably ok for you by bicatu · · Score: 5, Insightful

    Hi,

    The scenario you've mentioned is probably OK to use a software RAID. I use it in a production enviroment without problem with a higher stress that your setup will probably have.

    I'd suggest you to consider the following items :
    a) cooling system - those HD can generate a lot of heat. Buy a full tower case and add those HD coolers to make sure your HDs stay cool

    b) Buy the HDs from different brands and stores - RAID5 (either hardware or software) can recover from one drive. If you buy all from the same brand/store chances are that you end up with 2+ drives with the same defective hardware

    c) cpu - if you are going to use this number of drives the processor will be a majo bottleneck. Do not forget that RAID5 XOR your data to calculate the parity.

    d) partition scheme - use smaller partitions and group them together using LVM. This you help you to recover from a smaller problem without taking a lot of time to reebuild the array