Raid hard drives

By Predict
May 10, 2008
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  1. I want to go raid hard drives but do they have to be the same exact ones or can they be diff brands and size? I have two right now that are both 7200 rpm and 16mb but one is sata and other is the other slot.
  2. CCT

    CCT TechSpot Evangelist Posts: 3,556

  3. jobeard

    jobeard TS Ambassador Posts: 13,351   +301

    RAID is implemented on a per controller basis. All drives configured as a RAID array,
    must be on the same controller -- therefore -- be of the same architecture.

    SOME implementations allow differing sizes, BUT clearly a raid-1 (ie mirroring) requires
    the active size to be the same. Raid-0 (stripping) may not care.

    Consider carefully the implications of a failure on Raid-0; you must have a backup of
    the total RAID, or you loose everything and start over.

    Caveat Emptor.
  4. CMH

    CMH TechSpot Chancellor Posts: 2,572   +9

    I have just installed my first RAID array within the last 2 weeks, and I must say, that article seems to have one error:

    There is a performance increase using RAID 1.

    As usual, I benchmark every possible performance increase in my computer. Having just installed RAID 1, and RAID 0, here's my results:

    RAID 1:
    No increase in write speed.
    Significant increase in read speed.
    Major reduction in seek times.

    RAID0:
    Slight increase in write speed
    Major increase in read speed
    Slight increase in seek times

    These are in comparison to a single drive.

    The website might be assessing write speeds, which would mean it mirrors my results.


    To answer the original question:

    I think it may depend on your RAID chip itself. Most would support different sized disks (or just plain different manufacturer). However, for RAID 0 or RAID1, you'd lose the extra space on the bigger disk (or might have to partition it separately to make use of it, depending on whether your RAID chip would allow that).

    JBOD would accept all disks, and use them all. However, this is not a true RAID (come to think of it, RAID 0 is not a RAID at all neither). Not sure about performance difference in this setting.

    As for one SATA and the other not.... I got a feeling its going to be tricky. On motherboards, I doubt it can be done. May be possible on a RAID card which accepts both SATA and PATA.

    Bear in mind as well, that chances are, you'd need to reinstall Windows to get it to boot up on RAID.

    Hope that helps.
  5. Predict

    Predict Newcomer, in training Topic Starter Posts: 37

    Well I installed windows a couple days on my comp so I dont have much to lose. If i were to go raid im still not sure about raid 1 or raid 0. All I want is faster load speeds in games. Also do the hard drives have to be the same? Both diff brand, size, and one is sata other is ata. Both same speed thow.

    The guys says back up your still meanig it could erase ur hd? all i have to lose is some games.
  6. CMH

    CMH TechSpot Chancellor Posts: 2,572   +9

    Diff brands/size probably won't be a huge problem. However, different connectors (SATA and PATA) will cause problems for sure.

    Bear in mind that faster transfer speeds doesn't really mean much if the game loads tons of small files (like Windows does). In this case, a faster seek time would be more beneficial.

    For best performance from your RAID drives, identical drives should be used. Its been suggested that if you're worried about failing drives, RAID1 with different manufacturers/batches would provide the best data protection.

    I think a few RAID chips will preserve your data, while upgrading your configuration to RAID (Intel Matrix Storage comes to mind, on the ICH8R), but chances are you'd lose it. Backups don't hurt if you don't want to lose anything.
  7. jobeard

    jobeard TS Ambassador Posts: 13,351   +301

    One should expect this as that is the whole point of raid-0 :)
    This is a side benefit of the multiplicity of HDs -- eg having two HDs will have
    read performance like a single drive with two sets of arms+heads.
    The controller will seek and read from the drive that has the arm+head closest to
    the desired block. As long as there are consecutive read requests, the split reads continue to
    increase read data performance. However, as soon as there is a write, both arms seek
    and write in parallel and the read benefit starts all over again.
  8. CMH

    CMH TechSpot Chancellor Posts: 2,572   +9

    Yeah, I know.

    Would like to point out that you quoted me stating my results. The website had a different set of results, showing no performance increase (and hence only redundancy as a plus) in RAID1.

    :D
  9. jobeard

    jobeard TS Ambassador Posts: 13,351   +301

    the explanation was intended for those less informed that might follow this thread :)
  10. dtor

    dtor Newcomer, in training

    Raid

    For speed AND security go the extra expense and purchase 4 identical drives,
    then setup the Raid0,1 configuration.. That way you have the best of both raid configs.
    From what I understand the drives must be of the same everything, i.e. the
    speeds, size and manufacturer. I personally wouldn't waste my time trying
    different hdds for Raid. Efficiency is the key here.
    IF the possiblity of losing everything isn't a big issue for you than use the
    Raid0 config. If you want security in Keeping everything then use the
    Raid1 config.
    If you can afford it do the Raid0,1 (4 identical drives). You may get away
    with 2 sata and 2 pata, but then you would lose the speed factor. Keep it
    all in the groove, stay identical.
  11. CMH

    CMH TechSpot Chancellor Posts: 2,572   +9

    LMAO, this guy is trying to use his old SATA and PATA drives to form a RAID. What makes you think he would want to "go the extra expense and purchase 4 identical drives"?
     
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