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RAID1 & RAID10 for 8 disks - what're differences ?

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  • RAID1 & RAID10 for 8 disks - what're differences ?

    Hi,

    As I understand, RAID1 should for 2 disks (mirror), while RAID10 for more (mirror & span).
    Yet, I found from IBM x3650M3 RAID Manager, I can choose RAID1 for 8 disks or RAID10 for 8 disks. For both, I can use the same disk space ( = 4 disks' capacity).

    I don't know what're differences between RAID1 & RAID10 in this case. I also did a search and read the MegaRAID User guide for explanation but couldn't clear, maybe because of my bad English or the document didn't mention about RAID1 for more than 2 disks.

    Can anyone help to explain to me the differences in this case ? I care much about the performance (read/write for SQL Logs) and fault tolerance.

    Thanks so much.
    Love in vain is better than love no one.

  • #2
    Re: RAID1 & RAID10 for 8 disks - what're differences ?

    The difference is in the way the files are written - with RAID 10 they are broken into chunks and written across multiple disks in the stripe, as well as being mirrored to the other stripe. In RAID 1 they are written to a drive, and mirrored to its copy. RAID 10 will offer somewhat better write and read performance as all spindles are in use
    Tom Jones
    MCT, MCSE (2000:Security & 2003), MCSA:Security & Messaging, MCDBA, MCDST, MCITP(EA, EMA, SA, EDA, ES, CS), MCTS, MCP, Sec+
    PhD, MSc, FIAP, MIITT
    IT Trainer / Consultant
    Ossian Ltd
    Scotland

    ** Remember to give credit where credit is due and leave reputation points where appropriate **

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    • #3
      Re: RAID1 & RAID10 for 8 disks - what're differences ?

      Originally posted by Ossian View Post
      In RAID 1 they are written to a drive, and mirrored to its copy.
      Thanks for your explanation. As above, can I understand that there're also 4 disks with 4 mirrored disks here and when a file written in 1 disk (full file written in 1 disk), it will be mirrored to one of 4 mirrored disks ? In this case, how can I know which disk is the mirror disk of a certain disk ?
      Love in vain is better than love no one.

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      • #4
        Re: RAID1 & RAID10 for 8 disks - what're differences ?

        The RAID controller will determine that - you will have (for 8 drives)
        1A, 1B, 1C, 1D mirrored to 2A, 2B, 2C, 2D

        So the "A" drives mirror each other, as do "B" etc.
        Tom Jones
        MCT, MCSE (2000:Security & 2003), MCSA:Security & Messaging, MCDBA, MCDST, MCITP(EA, EMA, SA, EDA, ES, CS), MCTS, MCP, Sec+
        PhD, MSc, FIAP, MIITT
        IT Trainer / Consultant
        Ossian Ltd
        Scotland

        ** Remember to give credit where credit is due and leave reputation points where appropriate **

        Comment


        • #5
          Re: RAID1 & RAID10 for 8 disks - what're differences ?

          I like to visualise the setup (no imagination see) so have a look at the following links and see if that helps.

          http://en.wikipedia.org/wiki/RAID

          https://www.google.com.au/search?q=r...2&ved=0CEIQsAQ
          1 1 was a racehorse.
          2 2 was 1 2.
          1 1 1 1 race 1 day,
          2 2 1 1 2

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          • #6
            Re: RAID1 & RAID10 for 8 disks - what're differences ?

            Originally posted by Ossian View Post
            The RAID controller will determine that - you will have (for 8 drives)
            1A, 1B, 1C, 1D mirrored to 2A, 2B, 2C, 2D

            So the "A" drives mirror each other, as do "B" etc.
            Thanks, I understand.

            Thanks for your link, biggles77. Actually I had checked the link http://en.wikipedia.org/wiki/RAID but they give example for only 2 disks. I also searched "RAID 1 for more than 2 disks" to see if there's a visualize image but couldn't find.
            Love in vain is better than love no one.

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