my tuppence - looked at this in some depth this year.

In a completely homogenous environment, the EMC Timefinder product can be
used to take a 3rd mirror copy offline - ie quiesce the filesystem, unmount
it if the O/S isn't integrated with Timefinder (I heard HP-UX is - is that
so?). Next, if you have an ADSM server also attached to the EMCs you can
have the volume which was split off made available on the system hosting the
ADSM instance. After that its business as usual with ADSM - at file level.
Use a proper job scheduler though - don't try this with ADSMs scheduling and
pre/post hooks.

There are some gotchas depending on the O/S - the offline mirror copy is
physically identical to the disks it mirrored - including the signature so
some O/Ss will not like this. Logical volume managers also bitch (I managed
to really break an AIX odm with this). There are workarounds and EMC
profe$$ional $ervice$ will always be happy to help.

In short, if your ADSM server platform is a different O/S from your clients
or isn't connected to EMCs don't even try any of this.

Now 'other' backup products are slightly (a year IMHO) ahead of the game
here. There are proper hooks into Timefinder from some of them. I would
expect to see ADSM become more EMC aware as the two companies now talk since
the storage technology agreement they came up with last year (please).

Apart from the trivial advantages these hooks provide look out for a product
called Celestra (was Intelliguard - bought out by Legato) which implements
proper LAN free *and* (almost) serverless backup today and is integrated
with both Legato and Veritas Netbackup (ADSM enterprise users always weep at
this point because everything gets in those products first). The protocols
that Celestra uses are becoming SNIA standards and are being assisted by
implementations in the SAN fabric itself - which hopefully means ADSM will
support them - SOON. This is NDMP managed also - another area where one day
ADSM will catch up. (NetApp filers and EMC Celera use this protocol to
control backups).

What is the advantage of this - well it means your client CPU isn't being
bothered with all that IO to send changes to the backup server, it just has
to send index data - your backups get done over a dedicated fibre network
and your host doesn't grind to a halt while its happening. The Legato folks
have some interesting graphs somewhere.

I'll shut up now and leave some email bandwidth for others. I do prefer ADSM
overall for the most of the challenges I've been asked to solve. Hope this
is useful.

Alan