An administrator notices that the database virtual machines fail to backup within the backup
window. Each database virtual machine has 4 vCPUs, 16GB RAM and 12 virtual disks.
There are 16 database virtual machines to backup using 8 backup jobs. Which is the
simplest way to improve the backup performance for these virtual machines?
A.
Upgrade the array to 8GB FCP and ensure multipathing is configured properly.
B.
Add a backup job for each virtual machine.
C.
Set a 16GB reservation for each virtual machine.
D.
Add 1MB VMDK drives at 1.0, 2.0 and 3.0 on the VDR appliance.
D is right, if the number of vdisks of a single job (composed of several systems and executing simultaneously) is larger then the number of possible scsi devices, the backup job runs over the network instead over the SAN.
This can slow down backup times considerably. Moreover you need to createone Dummy drive per SCSI controller added.
Adding in additional scsi controllers (4 controllers x15 IDs = 60 vDisks) can be backed up in a single run.
In our scenario we have on average 2 DB servers per job (16DB servers on 8 jobs) with 12 disks each , or 24 vDisks per job.
This is explained in :
VMware Data Recovery Administration
Guide
Data Recovery 1.2