For the sake of this conversation, with the use of RDM's and in regards to quiescing and flushing buffers, treat it as you would a physical server;   therefore, these tasks would be handled within the guest image.  As you know, SAN Copy is an array based strategy so by itself would not provide application consistent copies, but instead would be considered crash consistent without some external consideration.  To achieve application consistency, you could, for example, use Replication Manager as already suggested (quick comment, RM supports RDM's in physical compatibility mode only), of course power down the image if possible, or if left online would need to some other external assistance.  So in the example of straight filesystems, as you originally inquired about and without powering down the guest image, where the data is being shared out, one possible strategy could be kicking users out of the shares via the computer management mmc plug-in and disabling the server service both of which would handle the "application", in this case file sharing.  Then you would also want to flush the operating system buffers using the Microsoft/SysInternals sync application as suggested above, or we offer the same functionality via EMC admsnap which can be downloaded from PowerLink.  Unlike Unix with the native "sync" command, Windows doesn't have a native tool to do the same thus the reliance on third-party utilities.  The syntax for admsnap in this case is simply:  admsnap flush -o   For your scenario, the object would likely be a drive letter (or maybe a folder if the LUN was not assigned a drive letter). 
Hi all, I'm looking for some guidance or a whitepaper on best practice to SANcopy RDMs. Environment is  ESX4.0 and CX4-120 replicating to AX4 CX4 is running Flare 29 VMs accessing RDM disks are Windows Server 2003 and 208R2 RDMs are data disks only, no opsys, no databases, flat files only. I'm happy to risk the files that are open with user applications that cannot be controlled from Windows as this is for a DR situation, not backup but would of course prefer to make the disk at neat as possible. Each RDM is on a seperate LUN  Can I just SANCopy the CX4 LUN to the AX4 ? Does ESX4 know about this and at least flush its own buffers ? Does windows server know anything and will at least try to flush as well ?  I've tried to find a paper on the powerlink site ( as we have support ) but nothing jumps out at me...so any pointers would be appreciated.  (I will address the SQL database and exchange disks on VMDKs at a later time..these are currently snapped using vmtools via GhettoVCB )
ESX4, Clariion and SANCopy, quiesce and flush buffers.