From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Braam Date: Mon, 22 Sep 2008 14:58:56 +0800 Subject: [Lustre-devel] Doubly indexed tree / changelogs In-Reply-To: <48D732B9.6090309@sun.com> Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lustre-devel@lists.lustre.org Objects can be in many filesets, and be added to some, removed from others. I think this is an almost arbitrary collection of pairs (FID, fileset-id) and we need it indexed by both. Peter On 9/22/08 1:52 PM, "Alex Zhuravlev" wrote: > can object migrate between filesets? if not, we probably > can use fid's sequence as a record in that index? > > thanks, Alex > > Peter Braam wrote: >> Hi Nikita, Nathan - >> >> After some pondering I have come to two conclusions. >> >> To encode filesets, we need a tree that makes two iterations fast: >> >> 1. list all filesets that contain a certain object >> 2. list all objects in a certain fileset >> >> >> Is there a doubly indexed tree for this? >> >> Secondly, to make the changelogs useful and scalable for filesets we >> will need to be able to list all changelog entries associated with a >> certain inode efficiently. I see two ways to do this ? one is an >> auxiliary directory file mapping inodes to many changelog entries, the >> second is to embed forward and backward pointers in the changelog >> entries to build a linked list rooted at the inode (using an EA in the >> inode pointing to the first and last element of the list). Both have >> some overheads. What are your thoughts? >> >> Peter >> >> >> ------------------------------------------------------------------------ >> >> _______________________________________________ >> Lustre-devel mailing list >> Lustre-devel at lists.lustre.org >> http://lists.lustre.org/mailman/listinfo/lustre-devel >