In our environment if we perform a VMWare snapshot of a SQL 
or Oracle database it will crash. So we've actually set policy so those do not 
get snapshots.
I've been experimenting with SMVI some and it 
appears to work hand-in-hand with vCenter.  Essentially, it takes a VMware 
snapshot, followed by a filer snapshot (and snapmirror update if you tell it 
to), then deletes the VMware snapshot.  The VMware snapshot before the 
filer snapshot ensures the volumes are quiesced and buffers flushed before the 
filer snapshot to ensure consistency.
 
I think you'll still have to place your databases 
in hot backup mode before taking a snapshot.
 
Currently our Oracle and SQL data, index, redo, and 
archives exist on iSCSI LUNs with SnapDrive for Windows.  As we progress 
with VMware, we will likely place our OS and Applications either on NFS volumes 
or VMFS formatted iSCSI LUNs.  We will then continue to use SnapDrive for 
Windows to manage our database LUNs as this is something we are familiar with 
and are very comfortable with our current recovery model in regards to the 
databases themselves.  Plus we often wish to take snaphots on them several 
times a day during our production cycles.  Simply go into hot backup mode, 
take snapshot of all but archive volumes, exit hot backup mode, snapshot archive 
volume.  It happens so quickly our users never notice it and we have 
recovery points at key times during our production cycle should something go 
wrong during one of the daily operations.  This is for Oracle.  Our 
SQL databases are small and not mission critical so simply taking a filer 
snapshot and letting SQL do its crash recovery if we restore a snapshot works 
fine.
  ----- Original Message ----- 
  
  
  Sent: Thursday, January 08, 2009 2:41 
  PM
  Subject: SMVI - Limitations?
  
  We're making the plunge to move to NFS and SMVI 
  (from RDM backed luns and homegrown snapshot management 
  scripts).
  Does anyone know of any limitation to how many VMs can 
  exist in a data store that SMVI is snapping? Is there any 
  impact when snapping virtual machines (outside of SQL/Oracle 
  VMs)?  
   __________________________________________________________
Ken Williams
Storage Administrator, Business Technology Operations
Sacramento 
  Municipal Utility District
E-Mail: kwillia@smud.org
Phone: (916) 732-6744
Cell: (916) 240-4213