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    SubjectRe: very poor ext3 write performance on big filesystems?
    Mark Lord wrote:
    > Theodore Tso wrote:
    > ..
    >> The following ld_preload can help in some cases. Mutt has this hack
    >> encoded in for maildir directories, which helps.
    > ..
    >
    > Oddly enough, that same spd_readdir() preload craps out here too
    > when used with "rm -r" on largish directories.
    >
    > I added a bit more debugging to it, and it always craps out like this:
    > opendir dir=0x805ad10((nil))
    > Readdir64 dir=0x805ad10 pos=0/289/290
    > Readdir64 dir=0x805ad10 pos=1/289/290
    > Readdir64 dir=0x805ad10 pos=2/289/290
    > Readdir64 dir=0x805ad10 pos=3/289/290
    > Readdir64 dir=0x805ad10 pos=4/289/290
    > ...
    > Readdir64 dir=0x805ad10 pos=287/289/290
    > Readdir64 dir=0x805ad10 pos=288/289/290
    > Readdir64 dir=0x805ad10 pos=289/289/290
    > Readdir64 dir=0x805ad10 pos=0/289/290
    > Readdir64: dirstruct->dp=(nil)
    > Readdir64: ds=(nil)
    > Segmentation fault (core dumped)
    >
    > Always. The "rm -r" loops over the directory, as show above,
    > and then tries to re-access entry 0 somehow, at which point
    > it discovers that it's been NULLed out.
    >
    > Which is weird, because the local seekdir() was never called,
    > and the code never zeroed/freed that memory itself
    > (I've got printfs in there..).
    >
    > Nulling out the qsort has no effect, and smaller/larger
    > ALLOC_STEPSIZE values don't seem to matter.
    >
    > But.. when the entire tree is in RAM (freshly unpacked .tar),
    > it seems to have no problems with it. As opposed to an uncached tree.
    ..

    I take back that last point -- it also fails even when the tree *is* cached.


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