Per the Solutions Enabler SYMCLI 7.3.1 Command Reference, here is what the Concurrent flag does:  When specified with the verify argument, this option verifies the standard device and multiple target devices. When specified with active commands, this option performs the operation on a pair with an additional target device.  Here is some additional information from teh Solutions Enabler Symmetix TimeFinder Family CLI Version 7.3.1 Product Guide:  Pairing an additional target device with each source device in a group When working with either a composite or device group, you can use the -concurrent option with the create action to pair an additional target device with each source device in a group. To pair an additional target device with each source device in group ProdDB, enter: symsnap -g ProdDB create -concurrent  When the copy session is created, an additional target device will be paired with each source device in the group. For example, if there were two target devices paired with each source device in the group before activating the session, there will be three target devices paired with each source device after the session is activated. To verify that each source device in the group has multiple targets, enter: symsnap -g ProdDB verify -created -concurrent  When working with either a composite or device group, you can use the -concurrent option with the activate action to activate an additional copy session for each device pair in a group. To activate an additional copy session for each device pair in group ProdDB, enter: symsnap -g ProdDB activate -concurrent
I am having trouble understanding what the -concurrent option on the symsnap create and activate acutally do. I need two sets of snap devices for each application. Rather than creating one device group with two sets of VDEVs for each STD, I have created two device groups, appSNAP1, and appSNAP2, each with the same set of STD devices and a different set of VDEVs. This makes it easier to get the VDEVs I want on a simple create, activate or terminate. I think I get the same result creating or activating the second set of VDEVs using the second device group regardless of whether or not I include the -concurrent option. I was thinking that maybe its because i am using two seperate device groups, and the concurrent option is irrelevant in this case. But I'm pretty sure that earlier in my testing when I was working with a single device group and two sets of VDEVs, I was gettting the same result without the -concurrent option, which I wasn't even aware of at the time.  I would appreciate any light that anyone can shed on this.
symsnap -concurrent option