Part of the difference is just an accounting/reporting one. UFS and most other file systems cache data in "unmapped" pages. This page caching looks like "free" memory, since the pages are easily reclaimed for other uses. However the kernel has to map the pages into virtual memory to access the data.
ZFS caches data in memory that remains mapped by the kernel, so the cached data looks like memory used by the kernel. ZFS knows how to work with the kernel to free this memory if needed, so it for the most part works the same. The biggest difference is that if you look at how much memory is free vs. how much is in use by the kernel, you'll see very different numbers. This message posted from opensolaris.org _______________________________________________ opensolaris-discuss mailing list [email protected]
