Chris Mason wrote: > On Thu, May 21, 2009 at 02:43:52PM -0400, Josef Bacik wrote: >> Hello, >> >> Okay I'm looking at redoing all of this stuff again, and I'd like to make >> this >> the last time, so I'm going to outline what we currently have, what the >> problems >> are with it, and what I want to do. I would appreciate any/all input so I >> can >> try and get this right the first time. >> > > Josef and I hashed this out someone on IRC. I think the bitmaps alone > aren't going to scale all that well for huge filesystems, so he is > looking into a hybrid bitmap/extent approach based on the size of the > free space.
I don't know if this is of any interest but I thought I'd provide a pointer to the AdvFS design spec for space allocation. http://advfs.svn.sourceforge.net/viewvc/advfs/advfs_design_docs_v1/porting_designs/storage_allocation.pdf?revision=1 The Tru64 version of AdvFS used bitmaps but this was changed during the port to HP-UX to use a combination of b-trees. Both the original and new designs are discussed in section 2 of the spec and there's a description of other design options considered but then rejected. The docs in the original tarball I posted were not very user friendly so I checked them into an svc tree to make them a little easier to browse. If it will be useful, I can do the same with the source code. -- ljk > -chris > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
