On Fri, Aug 15, 2003 at 11:54:28PM -0700, girish dudhe wrote:
> hi all,
>
> In XFS,whole file systen is divided into number of
> allocation group. e.g. Consider size of the file
> system is 1GB ,then it will create eight allocation
> group that means each has 125 MB.Each allocation Group
> has its own inodes and data blocks.
That is correct.
> Now I want to store the file of size 500MB.How it
> gets stored ? Whether it gets stores in one allocation
> group or multiple allocation group?
Since it cannot be stored in one allocation group (500 > 125),
it will be stored in multiple AGs (assuming it is not a sparse
file ;). File extent maps use the full disk addresses, and so
are not allocation group relative and can span multiple AGs if
necessary. A single extent can never span more than one AG.
The xfs_bmap(8) command will show you the block map for a
given file, and you can see which allocation group each of
the extents lives in using the -v option, iirc.
cheers.
--
Nathan
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