For some time now I''m looking for a technical explanation how a UFS file system compares with a ZFS file system. What I would like to know is: how are inodes and datablocks incorporated in ZFS. I do not think that ZFS actually uses inodes and datablock but how is a file written to ZFS. Where are file permissions (ACL) stored, where is the owner of a file stored, etc. This message posted from opensolaris.org
Peter - We have an on-disk format document which is nearing completion. Once it''s done we''ll post it to the ZFS community website. It should hopefully give you all the information you need. - Eric On Wed, Nov 16, 2005 at 01:48:04PM -0800, Peter van Gemert wrote:> For some time now I''m looking for a technical explanation how a UFS file system compares with a ZFS file system. What I would like to know is: how are inodes and datablocks incorporated in ZFS. I do not think that ZFS actually uses inodes and datablock but how is a file written to ZFS. Where are file permissions (ACL) stored, where is the owner of a file stored, etc. > This message posted from opensolaris.org > _______________________________________________ > zfs-discuss mailing list > zfs-discuss at opensolaris.org > http://opensolaris.org/mailman/listinfo/zfs-discuss-- Eric Schrock, Solaris Kernel Development http://blogs.sun.com/eschrock
Peter van Gemert wrote:> For some time now I''m looking for a technical explanation how a UFS file > system compares with a ZFS file system. What I would like to know is: how are > inodes and datablocks incorporated in ZFS. I do not think that ZFS actually > uses inodes and datablock but how is a file written to ZFS. Where are file > permissions (ACL) stored, where is the owner of a file stored, etc.There are a variety of blogs which (iirc) cover this. You might find my presentation (produced with the assistance of Jeff Bonwick, http://blogs.sun.com/bonwick) handy to get some basic structure. View it at http://blogs.sun.com/roller/page/jmcp?entry=another_cool_ad Then there''s the code -- have a wander on over to http://cvs.opensolaris.org and look for usr/src/uts/common/fs/zfs.... When you''ve got more questions, come back and ask :) best regards, James C. McPherson -- Solaris Datapath Engineering Data Management Group Sun Microsystems
On Wed 16 Nov 2005 at 01:48PM, Peter van Gemert wrote:> For some time now I''m looking for a technical explanation how a UFS > file system compares with a ZFS file system. What I would like to know > is: how are inodes and datablocks incorporated in ZFS. I do not think > that ZFS actually uses inodes and datablock but how is a file written > to ZFS. Where are file permissions (ACL) stored, where is the owner of > a file stored, etc. This message posted from opensolaris.orgThere''s a document which an engineer wrote which describes the on-disk format of ZFS-- but it''s not released yet. Last I heard it was awaiting review by the project architects who have been busy for fairly obvious reasons. While this won''t give you an exact mapping from UFS data structures to those in ZFS, it should be helpful. Hopefully it will be ready in the next couple of weeks or few months. -dp -- Daniel Price - Solaris Kernel Engineering - dp at eng.sun.com - blogs.sun.com/dp
James C. McPherson wrote:> Peter van Gemert wrote: >> For some time now I''m looking for a technical explanation how a UFS file >> system compares with a ZFS file system. What I would like to know is: >> how are >> inodes and datablocks incorporated in ZFS. I do not think that ZFS >> actually >> uses inodes and datablock but how is a file written to ZFS. Where are >> file >> permissions (ACL) stored, where is the owner of a file stored, etc. > > > There are a variety of blogs which (iirc) cover this. You might find > my presentation (produced with the assistance of Jeff Bonwick, > http://blogs.sun.com/bonwick) handy to get some basic structure. View > it at http://blogs.sun.com/roller/page/jmcp?entry=another_cool_ad >ahem, that''s the wrong link :( try http://blogs.sun.com/roller/page/jmcp/20051017 and look for ''slideware'' Sorry for the misdirection. James C. McPherson -- Solaris Datapath Engineering Data Management Group Sun Microsystems