Bob Friesenhahn writes: > On Wed, 23 Sep 2009, Ray Clark wrote: > > > My understanding is that if I "zfs set checksum=<different>" to > > change the algorithm that this will change the checksum algorithm > > for all FUTURE data blocks written, but does not in any way change > > the checksum for previously written data blocks. > > This is correct. The same applies to blocksize and compression. >
With an important distinction. For compression,checksum a block rewrite will affect the next update to any fileblock. For the dataset recordsize property, a block rewrite on an existing multiblock file will not change the file's block size. For Multi-record file's, the recordsize is immutable and dissociated from the dataset recordsize setting. > > I need to corroborate this understanding. Could someone please > > point me to a document that states this? I have searched and > > searched and cannot find this. > Me neither, although it's easy to verify that setting the checksum property on a dataset does not induce the I/O that would be required for a rewrite of the bp. -r > Sorry, I am not aware of a document and don't have time to look. > > Bob > -- > Bob Friesenhahn > bfrie...@simple.dallas.tx.us, 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
