On Wed, 15 Sep 2010, Brandon High wrote:
When using compression, are the on-disk record sizes determined before or after compression is applied? In other words, if record size is set to 128k, is that the amount of data fed into the compression engine, or is the output size trimmed to fit? I think it's the former, but I'm not certain.
We have been told before that the blocksize is applied to the uncompressed data and that when compression is applied, short blocks may be written to disk. This does not mean that the short blocks don't start at a particular alignment. When using raidz, the zfs blocks are already broken up into smaller chunks, using a smaller alignment than the zfs record size. For zfs send, the data is uncompressed to full records prior to sending.
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
