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. Add a backup job for each virtual machine.
B. Set a 16GB reservation for each virtual machine.
C. Add 1MB VMDK drives at 1.0, 2.0 and 3.0 on the vDR appliance.
D. Upgrade the array to 8GB FCP and ensure multipathing is configured properly.
Correct Answer: C
Explanation/Reference:
When adding hard disks to the backup appliance, consider how many disks most virtual machines to be backed up have. Each backup appliance can back up 100 virtual machines, but a maximum of 8 virtual machines can be backed up simultaneously. Each disk on each virtual machine may be hot-added for the backup to occur. In the default configuration, the backup appliance has a SCSI adapter #0 and a SCSI disk #0 attached to the SCSI adapter. Since the first SCSI adapter has a system disk at SCSI 0:0, only 14 SCSI disks can be hot-added. As the backup of a virtual machine completes, that virtual machines disks are removed and subsequent backups can begin. In the default configuration, if the total number of disks for the virtual machines being backed up reaches 15, the disks are backed up over the network instead of through hot-add. If you are working with virtual machines with a greater number of disks, consider adding additional disks to the appliance. For example, if each virtual machine in your environment has 3 disks, some of the virtual machine disks are backed up over the network, and performance may be negatively affected. By adding a dummy disk of 1 MB to another SCSI bus adapter, the total available SCSI bus locations for hot-adding increases to 30, so all 8 virtual machines in the example given here can be backed up simultaneously using hot-add. Additional disks should be added in the sequence SCSI 1:0, SCSI 2:0, SCSI 3:0, and so on for as many or as few instances as are required. A virtual machine, such as the backup appliance may have up to 4 SCSI adapters, enabling a maximum of 60 available SCSI bus locations for hot-adding disks, which is sufficient for most environments.
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