clonefset of a advfs fileset

[Mulgund]

Is it not necessary to freezefs a multivolume advfs fileset domain before clonefset to get a absolute consistent copy of a source fileset?

[Mark Poeschl_2]

'freezefs' is more designed for H/W based cloning (e.g. Business Copy) than for the S/W based 'clonefset'. If your fileset is supporting an RDBMS you'll probably want to do whatever database action is appropriate to guarantee point-in-time consistency before issuing the 'clonefset' command.

[Mulgund]

Since clonefset of a fileset created on multivolume advfs domain
takes a definite time to complete the metadata copy, how will it ensure the point in time copy
in a highly active advfs fileset?

[Mark Poeschl_2]

Quote from the freezefs man page:

To allow coherent hardware snapshots in multivolume domain configurations,
filesystem metadata must be consistent across all volumes when the indi-vidual volumes are snapped or cloned.

End quote.

"Hardware snapshots" being the important phrase...

Bear in mind that freezefs operates across all filesets in a domain simultaneously. It is used to prepare to take a storage controller-based snapshot of each of the underlying volumes. Clonefset on the other hand operates on only a single fileset at a time and because it is an OS utility can be aware of AdvFS metadata updates as they occur. Storage controllers don't know anything about AdvFS - hence the need for a tool like freezefs.

[Venkatesh BL]

It is more applicable to cluster as CFS works on the client/server model. So, freeze fs would ensure that CFS clients don't touch the file system during backup.

[Mulgund]

From a earlier response..

"Clonefset on the other hand operates on only a single fileset at a time and because it is an OS utility can be aware of AdvFS metadata updates as they occur. "

Does clonefset ensure point in time copy of the metadata also (without freezefs)??

I am looking for information beyond what is given in the man page.

-Srinivas

[Venkatesh BL]

From the AdvFS Admin Manual:

"Because the fileset cloning process is done entirely within AdvFS, no special steps are needed to ensure the integrity of the AdvFS metadata."

Refer to "Backing Up and Restoring Data" topic (http://h30097.www3.hp.com/docs/base_doc/DOCUMENTATION/V51B_HTML/ARH96DTE/CHPTRBCK.HTM) for more info on freezefs and clonefset.

[Mulgund]

How about user data?

I saw this inthe same manual.
"To create a fileset clone, ensure that the data in the original fileset is in a consistent state."

[Mark Poeschl_2]

User data integrity needs to be ensured at the application level - hence my original statement about taking whatever RDBMS or other application steps are necessary to guarantee point-in-time integrity. As BL has said you don't need to worry about AdvFS metadata, but only the application knows for sure about its own data.

[Mulgund]

Yup! Thanks.