I have a huge problem with space maps on thumper. Space maps takes over 3GB and write operations generates massive read operations. Before every spa sync phase zfs reads space maps from disk.
I decided to turn on compression for pool ( only for pool, not filesystems ) and it helps. Now space maps, intent log, spa history are compressed. Not I'm thinking about disabling checksums. All metadata are written in 2 copies, so when I have compression=on do I need checksums ? Does zfs will try to read second block when zio_decompress_data will return error ? Is there other way to check space map compression ratio ? Now I'm using "#zdb -bb pool" but it takes hours. This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
