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    SubjectRe: NFSv3 client for Linux-2.2.5 ready for alpha testing...
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    Eric Werme USG <werme@zk3.dec.com> writes:

    > One thing that confused Tru64 Unix a while back was Sun clients writing
    > to Tru64 servers. We only support 8KB (or less) I/O sizes, and the Sun
    > clients really wanted to do 32 KB. So, we'd see the first 8 KB of many
    > 32 KB chunks, then the 2nd 8 KB, then 3rd, then 4th. Then the pattern
    > would repeat with the next set of I/Os.
    >
    > One (or both?) of our physical file systems saw this pattern and wrongly
    > concluded that the client was doing random access I/O, and that lead to
    > inefficient block allocation. If Linux clients do read ahead, that
    > might be confusing Solaris. Perhaps the 4 KB I/O size doesn't trigger
    > readahead. Hmm. If you read a file that you just created on Solaris,
    > I'd expect that to be in Solaris's cache and it shouldn't need to read
    > from the disk anyway.

    The latter is indeed quite puzzling, but the difference between the
    read/write speed to ramdisk and the read/write speed to harddrive
    indicate that the server-side caching is somehow failing. A tcpdump
    would indeed help in debugging this.

    Anyhow, implementing support for 32k rsizes didn't turn out to require
    much extra code, so I wrote it last night.

    Cheers,
    Trond

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