On Tue, Apr 28, 2009 at 12:58:25PM -0700, Andrew Wilson wrote: > I believe that Solaris always converts reads and writes into file mapped > I/O, so if the cached attribute is missing or set to "false" the VM pages > involved in that will be flushed, so you will see a small difference in > performance, but because the files still live in the ARC, it is much > smaller than with UFS, where the files have been completely flushed from > memory.
UFS reads and writes are converted to file mapped I/O because the VM is used to back the file cache. In ZFS, the read and write operations only perform file mapped I/O when the vnode has an existing file mapping in place. If the vnode doesn't, then the only place the data is cached is in the ARC. -j _______________________________________________ perf-discuss mailing list perf-discuss@opensolaris.org
