I work for Symantec Backup Exec Support.
To the original posters question about replication, You can schedule backup exec to duplicate the job from one device to the other device. Which gives you information in backup exec to know when it happened and if it was successful. Incase of a failure, no matter which method used, You have to inventory and catalog the device before performing restores. Some admins, will just swap the names or IP addresses. So if you backup to Primary and duplicate to secondary. If primary fails, they will just change the info on Secondary to mimic Primary and Inventory / catalog it. Than can perform resore or backup to. If both are added in backup Exec, just inventory and catalog it, than you can perform restores or target jobs to it.
I find it easier to let the devices do it. if you have 2 matching devices with the ability to replicate between them. I let the appliance do it. The benefit from it, normally is it wors at block level. So if you Backup To primary and it gets deduplicated, than the replication happens, to secondary VIA the appliance, it normally does the block data and its intelligent about it.
When Backup Exec performs a duplicate job, the data has to be given back from the appliance to backup exec which than tranfers it to the other appliance, which Backup Exec dosn't really know they are identical devices. When the appliances do it in the background there is normally better connection / application on the device doing that.
On OST vs CIFS using most appliances. (new to me that an OST device can't be replicated or deduplicated. The point of OST is that its a standard that can be deduplicated and replicated) I will research this more and reply back later.
There are many advantages to using OST. Most OST devices like Data-Domain and Netapp and exagrid. Have great support for OST. If you purchase one of these device you will always want to use OST. this requires the Licensing of a deduplication license in Backup Exec. but you get so many benefits.
There are direct API calls with OST, that allow multiple read / write threads. It allows direct access and client side dedulication. Allows servers that are backed up direct access to the OST device instead of through Backup Exec. All of this has increased performance and reliability.
Using CIFS with a B2D has limited connetivity, no direct access, but works just like a B2D folder. Some application GRT or Exchange GRT. Will have resoure or failures when writing to B2D. This is from the limited read / write access to the device through Backup Exec. Some appliances work better than others.
DataDomain is one where if you use OST and the DDBoost plugin they have for their OST appliances where direct access and multiple read / write threads allow application and exchange GRT to work with our resource errors, you also notice MAJOR throughput increases. As much as 20 times the bandwidth.
As a Deduplication and OST tech I would always recommend anyone who has an OST device to purchase the deduplication license and use OST to boost performance. if you have a small environment and simple setup. Just backing up files and time is not a concern, simple B2D on Cifs will work and should have no issues.
If you have a large environment with Vmware / Hyper V, Doing AVVI or Hyper V backups with Application GRT, or even exchange backups with GRT. Getting throughput or backup time issues, You can trial dedupe, configure OST and create an LSU on your OST device. Download the plugin from your provider and configure an OST / LSU storage share and test the backups to that. See if the errors or performance increases. If it does, than you can decide which is better for you. if you encounter the same issues or errors, it is possible your seeing a different issue.
