On Thu, 4 Feb 2010, Darren J Moffat wrote:
Thanks - IBM basically haven't test clearcase with ZFS compression
therefore, they don't support currently. Future may change, as such my
customer cannot use compression. I have asked IBM for roadmap info to find
whether/when it will be supported.
That is FUD generation in my opinion and being overly cautious. The whole
point of the POSIX interfaces to a filesystem is that applications don't
actually care how the filesystem stores their data.
Clearcase itself implements a versioning filesystem so perhaps it is
not being overly cautious. Compression could change aspects such as
how free space is reported.
As I recall, Clearcase maintains a database (on top of a filesystem)
on a central server to store the actual data. When a user checks out
a view of the files, the user views the files via a versioning
filesystem, which stores a cache of those file on the local system.
Clearcase intruments access to its versioning filesystem so it knows
all of the actions which resulted in a built object. This means that
there are two places (server and client) where zfs may be involved.
Bob
--
Bob Friesenhahn
bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
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