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From Marc Sturlese <marc.sturl...@gmail.com>
Subject LocalDirAllocator and getLocalPathForWrite
Date Wed, 05 Jan 2011 16:35:41 GMT

I have a doubt about how this works. The API documentation says that the
class LocalDirAllocator is: "An implementation of a round-robin scheme for
disk allocation for creating files"
I am wondering, the disk allocation is done in the constructor?
Let's say I have a cluster of just 1 node and 4 disks and I do inside a
reducer:
LocalDirAllocator localDirAlloc = new LocalDirAllocator("mapred.local.dir");
Path pathA = localDirAlloc.getLocalPathForWrite("a") ;
Path pathB = localDirAlloc.getLocalPathForWrite("b") ;

The local paths pathA and pathB will for sure be in the same local disk as
it was allocated by new LocalDirAllocator("mapred.local.dir") or is
getLocalPathForWrite who gets the disk and so the two paths might not be in
the same disk (as I have 4 disks)?

Thanks in advance
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