The primary points of interest are related to ZFS. They are already mentioned in Chapter 6, ZFS – Now You Can’t Ignore It, as being potentially available in Solaris 10, but they are significant enough that they are worth calling out in an explicitly named section here.

The big feature additions of automatic compression, deduplication, and zfs diff can all be added into Solaris 10 via patching. Please refer to the relevant chapter for full details on how to use them.

Additionally, a significant bug related to free space and speed was patched in ZFS. It used to be such that, once any ZFS filesystem reached 80 percent, a significant performance hit was taken by any writes occurring on that filesystem and potentially anywhere in the same pool.

To get the fix for this (as well as to enable the newer features) it is crucial to fully patch the Solaris 10 system and also to upgrade both the ZFS pool version and the ZFS filesystem version, wherever these things are a concern.

Please note that, while the ZFS pool version update is relatively fast and painless, the ZFS filesytem update is not. Running zfs upgrade can take minutes, if not hours, on a full filesystem and will write-lock the filesystem or, at best, heavily impact performance.