On Tue, Aug 22, 2006 at 04:04:50PM -0500, Neil A. Wilson wrote: > Do both compression and fixed record sizes work together?
Yes. > Our Directory Server uses a fixed page size (8KB by default) for > database records, so I'm in the habit of setting the ZFS recordsize to > equal the database page size. However, we also typically use > compression because it often helps improve write performance. Given > that compression would inherently result in variable-sized records > (based on how well the data can be compressed), is there any advantage > or disadvantage to us continuing to set the record size? Yes, you should continue to set recordsize.. The recordsize property sets the *logical* block size used by ZFS. If compression is turned on, each block (which may be at most eg. 8k if you have set recordsize=8k) is compressed and stored as a smaller block on-disk if possible. This does not change the record size, only the amount of space used to store that block on disk. Compression and the recordsize property therefore don't interfere with one another at all. Bottom line: If you are doing record-structured access, set recordsize. If you want to compress your data, set compression. --matt _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
