What are multiple
group backups/archives?
FlashNet allows you to specify multiple groups as the destination for
a write operation. You can use multiple groups to make copies of your
data, or to write backups using multiple drives, which considerably reduces
backup times.
When creating a backup using the Schedule Definition window, choosing
the Multiple Groups option allows you to select two or more groups as
the destination of the backup or archive. You must also choose one of
the multiple group operation types. There are two basic multiple group
operations: distribute and copy. Copy operations can be parallel or serial. |
Distributed backups
A distributed backup is written to multiple groups using multiple drives;
you must have as many drives available as groups across which you wish
to make the backup. A dtool process is launched for each group being written
to, and data is passed to each dtool by the distributor daemon. The distributor
attempts to balance the amount of data written to each group so that wherever
possible a similar percentage of the backup is written to each group.
It is envisaged that distributed backups will be used to write large backup
data sets, in order to reduce backup time. |
Copy backups/archives
When you select copy as the multiple group operation, you must decide
whether you want the copy operation to be parallel or serial. Each makes
a copy of your data set, but in a slightly different way. Parallel copies
write the same data to multiple groups at the same time, and therefore
you must have as many drives available as are required for the copies.
Serial copy writes the copies one after the other, and therefore you only
need one drive available.
As in distributed backups, a separate dtool process is generated for each
copy.
When using multiple group copies with archive operations, each copy of
every file must pass verification before the file is deleted. If any one
copy does not verify, the original file is not deleted.
It is envisaged that copy operations will be used primarily with archives,
so that multiple copies of archive data can be created. |
