On Thu, 15 Aug 2002, Kevin Passey wrote:

> What is the best size for a holding disk - is it a "how long is a piece
> string" or are there some optimal values.

It mostly a tuning thing that's up to you to decide what's best for you.

That said, I prefer my setups to have as a minimum, enough to hold any
single night's backup in its entirety.  Then if something bad happens
with the tape drive/media, the backups can run to completion spooled to
the holding disk(s) and in the morning I can solve the tape problem and
flush the holding disk(s) to tape then.  Also, having enough to hold all
of a single run allows you to take the greatest advantage of dumping
parallelism, thus getting your client backups finished as quickly as
possible.

Further improvements on this theme are, 1) enough holding disk to hold an
entire weekend's backups, and 2) enough holding disk to hold an entire
<insert length of your longest anticipated family vacation here>.

My motto:  Disk is cheap, don't skimp on holding disk.

-Mitch