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With mdadm one can create a raid with a fixed chunk. I am trying to have a line by line stripping of a file. In fact, I'd like my files to have there lines repartitioned across the RAID. I am wondering if this is possible given that the lines length vary across the files, but is the same within a file.

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Trying to get raid chunk sizes smaller than disk sectors would potentially be catastrophic in terms of performance. Line-level striping doesn't sound like a good idea - if you need fast line-level lookups, you should probably be looking at database software (on top of properly sized/chunked/striped RAID devices). –  Mat Aug 3 '12 at 8:03
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Also, stripe sizes are always constant across the array. If they weren't, calculating the physical location of a RAID block N would be considerably less than trivial (and this happens below the filesystem level and transparently to it, so files and lines don't enter into it.) –  Alexios Aug 3 '12 at 8:30
    
@Mat: Potentially my lines can be multiple megabytes. –  Djellel Eddine Aug 3 '12 at 8:54
    
@Alexios: is it every other strip of the disk that gets repartitioned across the RAID or of the files? I am asking because my program needs to know how the file is going to be fetched. –  Djellel Eddine Aug 3 '12 at 8:56
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Out of curiosity, what exactly are you trying to do in the first place and at a high level? Often, this sort of requirement is a result of a combination of misconceptions and tunnel vision, and the actual solution is much, much simpler. (but not obvious from the asked question) –  Alexios Aug 3 '12 at 10:10
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closed as too localized by Anthon, Mat, slm, vonbrand, jasonwryan Jun 9 '13 at 18:26

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