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Why do you want a single raid0 over 2 raid1 (Raid10) instead of one |
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raid1 over 2 raid0 (Raid01)? Greater survivability. |
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|
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Here is the potential setups: |
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|
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Raid01: |
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md0 (raid0): sda1 sdb1 |
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md1 (raid0): sdc1 sdd1 |
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md2 (raid1): md0 md1 |
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|
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Raid10: |
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md0 (raid1): sda1 sdb1 |
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md1 (raid1): sdc1 sdd1 |
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md2 (raid0): md0 md1 |
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|
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If sda1 fails: |
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raid01: md0 also fails (sdb now has garbage data), so md2 relies on |
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md1 for all data. If sdc or sdd fail, md1 will fail and all data is lost. |
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raid10: md0 keeps going by relying on sdb. If sdc or sdd fail md1 |
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will still function and thus md2 will continue to function. |
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|
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With 2 disks failing there are 6 possible combinations (ab, ac, ad, bc, |
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bd, cd). With raid01 there is only a 33% chance of avoiding data loss |
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(ab, cd). With raid10 there is 67% chance of avoiding data loss (ac, |
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ad, bc, bd). |
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|
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jbw |
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|
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Andrea Ferraris wrote: |
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|
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>>From: "Joby Walker" <zorloc@××××××××.org> |
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>>Andrea Ferraris wrote: |
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>> |
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>> |
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>>>>Other way around. A stripe set of 2, 2disk mirrors is the winner, but I |
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>>> |
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>>> |
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>>>Sorry I have some problems with the language (I'm not a native speaker, |
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>>>neither well understander ;-) |
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>>>Is it raid0 on top of 2 raid1? |
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>>> |
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>>> |
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>> |
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>>Correct. |
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> |
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> |
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> Why? ;-) |
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> |
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> Andrea |
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> |
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