For the record, what I said was the on x64, the default size of the UFS segmap segment, which is the L1 cache for UFS reads and writes, is 64MB. Caches pages will be moved to a cache list in memory if segmap fills up.
The message I was trying to convey is that the default size of the UFS segmap on x64 (64MB) is generally too small if UFS file IO is a component of your workload (and 64MB is the default for 64-bit x64). Check out; http://www.solarisinternals.com/wiki/index.php/Segmap_tuning For increasing the size. Note please do NOT use the /etc/system method of increasing segmapsize on x64 - it will panic your system. None of this has anything to do with ZFS, which uses a completely different mechanism for caching (the ZFS ARC). Thanks, /jim > What is what I heard Jim Mauro tell us. I recall feeling a bit > disturbed when I heard it. If it is true, perhaps it applies only to > x86 32 bits, which has obvious memory restrictions. I recall that he > showed this parameter via DTrace. However on my Solaris 10U5 AMD64 > system I see this limit: > > 429293568 maximum memory allowed in buffer cache (bufhwm) > > which seems much higher than 64MB. The "Solaris Tuning And Tools" > book says that by default the buffer cache is allowed to grow to 2% of > physical memory. > > Obtain the value via > > sysdef | grep bufhwm > > My 32-bit Belenix system running under VirtualBox with 2GB allocated > to the VM reports a value of 41,762,816. > > Bob > ====================================== > Bob Friesenhahn > [EMAIL PROTECTED], http://www.simplesystems.org/users/bfriesen/ > GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ > > _______________________________________________ > zfs-discuss mailing list > zfs-discuss@opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss > _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
