zfs discuss - Jun 2006 - ZFS uses compression even if it''s off?

Hi.

   All filesystems have compression set to off.


bash-3.00# zfs list -o compression|grep -i on
bash-3.00#

But still lzjb_compress() is ised by ZFS - is it for metadata or what?

bash-3.00# dtrace -n
fbt::lzjb_compress:entry''{@[stack()]=count();}''
dtrace: description ''fbt::lzjb_compress:entry'' matched 1 probe
^C


              zfs`zio_compress_data+0x9c
              zfs`zio_write_compress+0x68
              zfs`arc_write+0xbc
              zfs`dbuf_sync+0x6b0
              zfs`dnode_sync+0x300
              zfs`dmu_objset_sync_dnodes+0x68
              zfs`dmu_objset_sync+0x50
              zfs`dsl_pool_sync+0x108
              zfs`spa_sync+0xe0
              zfs`txg_sync_thread+0x130
              unix`thread_start+0x4
                1

              zfs`zio_compress_data+0x9c
              zfs`zio_write_compress+0x68
              zfs`zio_wait+0xc
              zfs`dmu_objset_sync+0x118
              zfs`dsl_dataset_sync+0xc
              zfs`dsl_pool_sync+0x60
              zfs`spa_sync+0xe0
              zfs`txg_sync_thread+0x130
              unix`thread_start+0x4
                1

              zfs`zio_compress_data+0x9c
              zfs`zio_write_compress+0x68
              zfs`zio_wait+0xc
              zfs`dmu_objset_sync+0x118
              zfs`dsl_pool_sync+0x108
              zfs`spa_sync+0xe0
              zfs`txg_sync_thread+0x130
              unix`thread_start+0x4
                2

              zfs`zio_compress_data+0x9c
              zfs`zio_write_compress+0x68
              zfs`arc_write+0xbc
              zfs`dbuf_sync+0x6b0
              zfs`dnode_sync+0x300
              zfs`dmu_objset_sync_dnodes+0x68
              zfs`dmu_objset_sync+0x78
              zfs`dsl_pool_sync+0x108
              zfs`spa_sync+0xe0
              zfs`txg_sync_thread+0x130
              unix`thread_start+0x4
                5

              zfs`zio_compress_data+0x9c
              zfs`zio_write_compress+0x68
              zfs`arc_write+0xbc
              zfs`dbuf_sync+0x6b0
              zfs`dnode_sync+0x300
              zfs`dmu_objset_sync_dnodes+0x68
              zfs`dmu_objset_sync+0x78
              zfs`dsl_dataset_sync+0xc
              zfs`dsl_pool_sync+0x60
              zfs`spa_sync+0xe0
              zfs`txg_sync_thread+0x130
              unix`thread_start+0x4
              208

              zfs`zio_compress_data+0x9c
              zfs`zio_write_compress+0x68
              zfs`arc_write+0xbc
              zfs`dbuf_sync+0x6b0
              zfs`dnode_sync+0x300
              zfs`dmu_objset_sync_dnodes+0x68
              zfs`dmu_objset_sync+0x50
              zfs`dsl_dataset_sync+0xc
              zfs`dsl_pool_sync+0x60
              zfs`spa_sync+0xe0
              zfs`txg_sync_thread+0x130
              unix`thread_start+0x4
              229
bash-3.00#
 
 
This message posted from opensolaris.org

Robert Milkowski writes:
 > Hi.
 > 
 >    All filesystems have compression set to off.
 > 
 > 
 > bash-3.00# zfs list -o compression|grep -i on
 > bash-3.00#
 > 
 > But still lzjb_compress() is ised by ZFS - is it for metadata or what?
 > 

Yes, for metadata.

-r