[Lustre-devel] Doubly indexed tree / changelogs

Alex Zhuravlev Alex.Zhuravlev at Sun.COM
Sun Sep 21 22:52:57 PDT 2008


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
> 
> 
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