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    SubjectRe: Unices are created equal, but ...
    > Whole Linux seems to be a memory file system ;-) They are caching
    > like hell. Only benchmarks like bonnie on files of about 3xRAMSIZE
    > address the fact that we want to bench the disk and not the RAM.
    > Gerard compares chicken with eggs. This Byte Bench is really
    > questionable.
    The most evil things about aggressively write cache are the memory starvation
    and sync issues. On FreeBSD we purposely decided to limit the amount of
    dirty cached file data. It can become a real problem with big memory
    systems!!! The AT&T GIS/NCR/Tandem boxes really acted badly when users
    would tune the system to allow too much memory to be dirty filesystem
    cache buffers. I could be convinced that 1/4 of memory for dirty buffers
    is okay, and in some cases even more could be considered. But those cases
    where a system could gain significantly from huge write caches are few
    and far between. I guess if managed VERY WELL, a large (>1/2 mem) write cache
    would be good -- I just haven't seen that yet.


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