I’ve gotten a whole lot of requests for “application-consistent” B/R support in SMVI and SMVI/SnapManager integration. Let me explain what I understand application-consistent B/R to mean and what SMVI provides today, and then I’d love to hear your feedback about what else is required.
Applications can be divided into 2 basic types:
(1)Infrastructure applications, or those applications – actually any data – that don’t require “special handling”. SMVI can backup up these today using VMware snapshots “underneath” NetApp Snapshots.
(2)Mission-critical applications, or those applications – like SQL, Exchange or Oracle – that do require “special handling”. There are 2 ways to handle mission-critical applications, and each has its advantages and disadvantages.
I apologize to all of you ... I realize that the wiki link I referred to is for an internal wiki page. I am in the process of getting a document with the same content approved for external consumption. Stay tuned ... I'll post as soon as I get the go-ahead.
1. Yes - This is currently the case within my organization.
2. Yes - I believe that this is becoming all the more prevalent, especially in environments where SnapMirror and VMware SRM are deployed.
3. Yes - Again, especially in environments where Snapmirror is used to replicate VMs to a remote DR site. It is essential that both the VM itself and the application data is consistent before it gets snapmirrored to the DR site. At present there seems to be a disconnect between the Snapmanager products as my understanding is thattaking quiesced VMware snapshots of virtual machines which have internally connected LUNs using the MS iSCSI initiator is not supported, and being that currently iSCSI is the only way to go when using SME/SMSQL in virtual environments it means that SMVI cannot be used to take a quiesced snapshot of a VM when used in conjunction with SME/SMSQL. This is something that I am currently struggling to figure out how to mitigate.
Just a side note on the VSS requirements. This is a selling point of SME, SMSQL and so on as they don't just integrate with VSS, but they integrate at the backup level. Using VSS alone isn't enough for Exchange or SQL to understand that a full backup has been performed and so they won't truncate their logs. There needs to be full application integration to get full consistency of mission critical applications. So no, VSS is not sufficient for these. And we also have to take into account the mission critical applications that aren't VSS aware, or at least not functionally advanced in VSS respects, like Oracle and SAP! I would position these as much more mission critical than say SharePoint.
But what if the SMAI tools had their own VSS writer, then a SMAI job could be triggered from a VSS call, which could be part of the VMware tools process of taking a snapshot. Maybe?