snapmirror is what you want.  you can set it up anytime prior to the migration and let it run on a schedule or manually to build the initial baseline.  after that you just do a snapmirror update to keep it in sync.

we have done this so many times it's second nature. quite simply:

1) create target volume and initialize snapmirror relationship to source while lun is live and serving data
2) setup maintenance window and take filesystem/lun offline
3) perform final snapmirror update
4) break snapmirror relationship and bring new lun/volume online
5) mount new lun/filesystem and serve up data

snapmirror is a really handy product :)

--
Daniel Leeds
Senior Systems Administrator
Edmunds.com



-----Original Message-----
From: owner-toasters@mathworks.com on behalf of Suresh Rajagopalan
Sent: Thu 4/26/2007 3:02 PM
To: toasters@mathworks.com
Subject: Data migration

I need to migrate a 1.4Tb lun from one filer to another with minimal
downtime (< 30 mins).  So clearly some copying of data has to be done
prior to the actual move. 



Would snapmirror or flexclone be the most appropriate for this?   I'm
not sure how I would get a consistent copy of the lun over to the other
filer.  This is not a database, the lun contains flat files on NTFS.



Thanks

Suresh