When ZFS compression is enabled, although the man page doesn't explicitly say this, my guess is that only new data that gets written out is compressed - in keeping with the COW policy.
This is all well and good, if you enable compression when you create the ZFS filesystem. If I enable compression at some later point, I may have decided that all the data for that filesystem is to be compressed (or uncompressed.) But what I can't see, currently, is a mechanism to go and compress/uncompress all of my old data. The only obvious solution I can see, currently, is to "zfs send" it all out to some other place and "zfs receive" it back with compression enabled, with a zfs destroy/create in the middle. Am I missing something? Or is there room for a "zfs compress" command here? Hmmm, well, I suppose the same problem might apply to encrypting data too...so maybe what I need is a zfs command that will walk the filesystem's data tree, read in data and write it back out according to the current data policy. This may not work so well for encrypted data if encryption is disabled, but I'm not sure that is such a good idea. Darren _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
