Dean,
We have a problem when managing an XFS filesystem using the DMAPI. When we
copy data from an XFS file to our archive, we cover the file with a DMAPI
region to inform us of read, write, and truncate events. However, if the
filesystem is full, we cannot establish this region, and we don't have a
good way to recover.
To fix the problem, we plan to preallocate a DM region to each file when it
is created. This region would not be set to generate any I/O events but
would serve only to preallocate storage. We could later modify the region
to generate I/O events. If we couldn't create the region due to space
constraints, we could just abort the file create.
I have two questions. First, will this approach work? Second, will the
pre-allocated region also preallocate space that could be used by DM
attributes? I'm guessing that it will allocate one block, stick the region
in there, and have lots of extra space for other extended attributes (i.e.,
DM attributes). I'm hoping that it will be enough to ensure that I can
create, modify, and remove some number of DM attributes without having to
worry about space shortages, but I have no idea how much space I'll have to
play with.
Any ideas or pointers you could give would be appreciated.
Thanks,
-James Goodwin
Software Engineer
IBM Business Consulting Services
jagoodwi@xxxxxxxxxx
Phone: (281) 336 2578
Fax: (281) 335 4231
T/L 260-2578
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