The length of allocator chains in the global bitmap depends on the size of the volume and block/cluster sizes. It is created during format and only grows if the volume is grown. That's it.
On 11/23/2010 11:04 AM, Norman P. B. Joseph wrote: > This is related to the "No space on OCFS2 volume" error discussed here > this past Sep/Oct. Our Oracle support rep pointed us to Metalink note > #1232702.1 and suggested we should script something up to periodically > check the free contiguous blocks in the group chains for the volume in > question. > > Reading the note, I get how to get Clusters per Group X Bits per Cluster > from the "stat //extent_alloc:NNNN". What I'm confused about is parsing > the "stat //global_bitmap" section, and I thought I might have a better > chance of getting an explanation from the audience here. > > I have 2 basic questions: > > 1) The note above says that a "highly fragmented volume will have many" > Group Chain entries in the //global_bitmap section, but gives no > guidance as to what constitutes "many". I see ~240 in the 56 GB OCFS2 > partition in question. Is that Low? High? Just Right? > > 2) The note also says to check the "Contig" values in the long list of > Group Chains that follows in the //global_bitmap section. Specifically, > "If none are higher than the sum[sic] of "Clusters per Group * Bits per > Cluster" the metadata extent file cannot be expanded..." Here is a > sample output below: > > Group Chain: 8 Parent Inode: 11 Generation: 1861766630 > CRC32: 00000000 ECC: 0000 > ## Block# Total Used Free Contig Size > 0 258048 32256 1026 31230 28159 4032 > 1 8096256 32256 1 32255 32255 4032 > > Group Chain: 9 Parent Inode: 11 Generation: 1861766630 > CRC32: 00000000 ECC: 0000 > ## Block# Total Used Free Contig Size > 0 290304 32256 30721 1535 1535 4032 > 1 8128512 32256 1 32255 32255 4032 > > Group Chain: 10 Parent Inode: 11 Generation: 1861766630 > CRC32: 00000000 ECC: 0000 > ## Block# Total Used Free Contig Size > 0 322560 32256 31745 511 511 4032 > 1 8160768 32256 1 32255 32255 4032 > > Group Chain: 11 Parent Inode: 11 Generation: 1861766630 > CRC32: 00000000 ECC: 0000 > ## Block# Total Used Free Contig Size > 0 354816 32256 30721 1535 1535 4032 > 1 8193024 32256 1 32255 32255 4032 > > Should I be considering -all- the Contig values from -all- the Group > Chains listed when looking for issues, or should I be considering each > chain individually? IOW, is it only a problem when -all- the Contig > values from -all- the chains are below the clusters X bits value, or is > it only a problem when all of the Contig values for a -single- chain are > below the cluster X bits value? > > Any pointers on valid interpretation of the output is appreciated. > > -Norm > > _______________________________________________ Ocfs2-users mailing list Ocfs2-users@oss.oracle.com http://oss.oracle.com/mailman/listinfo/ocfs2-users