Agentless Snapshot Question

Question

Rapid Recovery 6.2.1...esxi 5.5...if i decide to do agentless on some of my servers, what is the method of the snapshot being created? I know the agent uses VSS and the local RR logs to know what to backup in each snapshot in windows but wasnt sure how Rapid Recovery knwos what has changed when backing up via VMWare agentless. I did notice in the setup of the core a mention about merging vmware snapshots....so i wasnt sure if using snapshots was how the agentless backup worked with VMWare

phuffers · Answer

Agent-less backups for VMware are fairly straight forward, however they do have a few 'new' pieces to introduce if you're not familiar with the process. 
 The snapshot process is done on a .vmdk level within VMware, the snapshot is taken to remove the lock on the .vmdk and then the backup of (or from) the .vmdk is done. The changed blocks are tracking through VMware via Change Block Tracking (CBT) which is a VMware feature ( https://kb.vmware.com/s/article/1020128 ). 
 You mention that you are on ESXi 5.5. The version should be adequate, however you'll want to make sure you're on recent build of 5.5. If you're running 5.5 from 2014 you might run into more snapshot problems and/or VMware conflicts than if you were running a build from late 2018. 
 The rise and fall of most agent-less DP solutions revolves around a few factors: 
 
 ESXi builds being up to date 
 Virtual Center resources (RAM) - specifically, running the minimum resources needed to just install the VC isn't the best way to perform agent-less backups, 16 GB is a good start. 
 Job contention - agent-less backups alleviate resources on the RR core (generally) however they do increase overhead within ESXi. Just don't increase concurrent jobs to a bunch as the OS isn't be hit as hard 
 
 A few things to keep in mind/think of regarding agent-less backups: 
 support.quest.com/.../backing-up-virtual-center-with-rapid-recovery 
 support.quest.com/.../rapid-recovery-lan-free-san 
 support.quest.com/.../rapid-recovery-esxi-6-6-5-6-7-permissions

phuffers · Answer

It is per VM. CBT is VM based not host based. So if you have a host with 100 VMs and choose to backup 4 of them, just those 4 get CBT enabled.

phuffers · Answer

Correct, on all accounts. CBT will stay, I have yet in my professional career seen a product that will go back an turn off CBT automatically, some have toggled to turn it off through their GUI, however not auto. There is zero harm in leaving it on. In fact it is amazing how many times people bring VMs into protection and they don't get notified to turn on CBT, as it had already been enabled from another 3rd party product over time.