<<jean-marc.pascual  inquired about TimeFinder software>>

EMC has its TimeFinder software for the Symmetrix box and HP has its Business
Copy software for the XP256, and both solutions function pretty much the same
in that you can close the volume set and "split" a copy of the data from
machine 1 and mount the volume set on machine 2.

You can then do a backup on machine 2 while you move forward with other
activities on machine 1.  It can be a good way to offload report jobs or do
program testing using production data.

To do the split operation you must close the volume sets on both machines.
Both products, TimeFinder and Business Copy, have software on a PC which is
attached to the storage device, and this is where you issue control commands.

When you are ready to resynchronize the data, you close the volume set on
machine 2 and issue the appropriate command.  Machine 1 can continue doing
whatever it was doing and the data is copied from the "standard" volume to
the "copy" volume.  This is internal to the storage device and places no load
on the machines attached to the storage device.

There is a "restore" function as well.  In one instance we split the volume
to the BCV machine and expanded a VERY large database on our BCV machine (it
took about 36 hours).  The online users maintained read only access to the
production database.  Then on Sunday morning we "restored" from the BCV
volume to the standard volume in a matter of  a couple hours and the users
did not experience any downtime.

I'm not sure how many people are using this technology - it seems to be a
guarded secret.  We use it daily in our operation and have been doing so for
eight months.

One word of caution - be very careful in doing a restore.  Experiment with it
in a test environment before using it in a production environment.  I found
the EMC documentation to be less than completely clear for an HP3000
environment.

I have not used the HP solution, but my perception is that HP spent a lot of
time helping EMC implement the TimeFinder solution, and then improved upon it
for the XP256.  For instance the control PC uses a port on the Symmetrix box
but the XP256 has an internal LAN to the control PC.  One port is important
when you are spreading a TB or more of data over the available ports!

HTH

Dave Mullins