Backup Strategies for Integrity Virtual Machines

General Guidelines and Suggestions
Based on the scenarios presented here and some practical experience, there are some data
protection guidelines and pitfalls in a virtual environment you should be aware of.
Storage Configuration for Reliability
In several figures above a subtle but important storage configuration detail is illustrated – whenever
mirroring inside the guest, take care that the virtual disks in that mirror map to storage entities on
separate physical storage devices. Otherwise, the backup and recovery strategies for volume splitting
will fail to provide the data protection you are trying to achieve. For example, suppose that the two
virtual disks shown in Figure 6 map to logical volumes instead of LUNs. If those logical volumes
reside on separate disks or LUNs, then splitting the volume inside the guest will succeed in protecting
your data. However, if those two logical volumes reside on the same disk or LUN then your data is at
risk. This is because a failure on that physical disk or LUN may corrupt or destroy data on both those
logical volumes.
Plan for Recovery of the Virtual Environment
A good approach to protecting your virtual environment is to combine incremental backup practices
with disaster recovery planning. That is, in addition to regularly scheduled backups for the virtual
machines and the VM Host system, you should also consider periodically creating a recovery image
of the VM Host system. In doing so, you may fully recover the VM Host system in the event of a
disastrous failure on the physical system while also enjoying the granularity and flexibility provided by
the EBS software.
You can create recovery images with the Ignite tools mentioned above. An alternative is to use the
dynamic root disk capabilities on the VM Host system. Using the drd (q.v.) command, one can
create a recovery image of the root disk on the VM Host system that may be subsequently used to
recover the VM Host system in the even the primary root disk fails for whatever reason.
Best Practices for Using EBS on Integrity Virtual Machines
The accelerated virtual I/O (AVIO) capability of Integrity VM provides significant performance benefit
when backing up individual virtual machines. For best performance, define the virtual NIC used by
the EBS software with an accelerated virtual I/O (AVIO) network adapter for best performance. By
using AVIO storage adapters, you will incrementally improve overall performance and reduce load
on the physical system.
Configuration Tips for Backup and Recovery Software
The AVIO technology operates to its maximum potential when transferring data from multiple I/O
connections. Therefore, to get the maximum benefit from AVIO, configure your backups to use
multiple streams – at most one for each virtual disk. This will reduce the overall time needed to
backup the virtual machine while utilizing the physical system’s resources most efficiently.
When using Data Protector you increase the number of streams by changing the concurrency setting,
either per device or per backup specification. The concurrency per device defines the number of
parallel jobs sent to a device. The concurrency per backup specification defines the number of
parallel streams a backup specification can send. You can find details for configuring concurrency in
the Data Protector Administrator's Guide.
To increase the number of streams with NetBackup, you should increase the Maximum jobs per client
global attribute in your NetBackup configuration.