Resent, for Fred... Hi gurus, When creating some small files an ZFS directory, used blocks number is not what could be espected: hinano# zfs list NAME USED AVAIL REFER MOUNTPOINT pool2 702K 16.5G 26.5K /pool2 pool2/new 604K 16.5G 34K /pool2/new pool2/new/fs2 570K 16.5G 286K /pool2/new/fs2 pool2/new/fs2/subfs2 284K 16.5G 284K /pool2/new/fs2/subfs2 hinano# pwd /pool2/new/fred hinano# zfs get all pool2/new NAME PROPERTY VALUE SOURCE pool2/new type filesystem - pool2/new creation Tue Mar 20 13:27 2007 - pool2/new used 603K - pool2/new available 16.5G - pool2/new referenced 33.5K - pool2/new compressratio 1.00x - pool2/new mounted yes - pool2/new quota none default pool2/new reservation none default pool2/new recordsize 128K default pool2/new mountpoint /pool2/new default pool2/new sharenfs off default pool2/new checksum on default pool2/new compression off default pool2/new atime on default pool2/new devices on default pool2/new exec on default pool2/new setuid on default pool2/new readonly off default pool2/new zoned off default pool2/new snapdir hidden default pool2/new aclmode groupmask default pool2/new aclinherit secure default hinano# mkfile 9 file9bytes hinano# mkfile 520 file520bytes hinano# mkfile 1025 file1025bytes hinano# mkfile 1023 file1023bytes hinano# mkfile 10 file10bytes hinano# ls -ls total 14 3 -rw------T 1 root root 1023 Apr 4 13:34 file1023bytes 4 -rw------T 1 root root 1025 Apr 4 13:34 file1025bytes 1 -rw------T 1 root root 10 Apr 4 13:38 file10bytes 3 -rw------T 1 root root 520 Apr 4 13:33 file520bytes 2 -rw------T 1 root root 9 Apr 4 13:33 file9bytes After 2 seconds : hinano# ls -ls total 13 3 -rw------T 1 root root 1023 Apr 4 13:34 file1023bytes 4 -rw------T 1 root root 1025 Apr 4 13:34 file1025bytes 2 -rw------T 1 root root 10 Apr 4 13:38 file10bytes 3 -rw------T 1 root root 520 Apr 4 13:33 file520bytes 2 -rw------T 1 root root 9 Apr 4 13:33 file9bytes 2 questions : - Could somebody explain why a file of 9 bytes takes 2 512b blocks ? - Why the block number of file10bytes has changes after a while doing nothing more than ''ls -ls'' Please reply me directly as I''m not in this alias . Best, fred