Veritas NetBackup™ Appliance Capacity Planning and Performance Tuning Guide
- About this Guide
- Section I. Capacity planning
- Analyzing your backup requirements
- Designing your backup system
- Section II. Best Practices
- Section III. Performance tuning
- Section IV. Quick reference to Capacity planning and Performance tuning
General guidelines to spot a resource bottleneck
Identifying performance problem is not trivial, however, the following guideline can help quickly spot a potential problem:
CPU may be a bottleneck if us + sy from vmstat output is consistently over 85% and/or the r column is more than four times the number of CPU cores on the system
Memory may be a bottleneck if the value of "si" and "so" columns is consistently high in vmstat output (for example over 1000).
I/O subsystem may be a bottleneck if the await column of VxVM device show greater than 25(ms). Another way to detect I/O bottleneck is continue increasing the load with an I/O intensive workload. When the throughput stop increases but the await time increases substantially, then it is very likely that the I/O subsystem is saturated.
Network may be a bottleneck, if the sum of "in" + "out" is close to 1.2 GB/sec from ifstat output on a 10 Gbps or 120 MB/s on a 1 Gbps NIC.
For the first three items, consider lowering the batch size of concurrent jobs. Overall throughput may be better than overstressing the system because excessive jobs will most likely be on an internal queue somewhere waiting for resources to free up. For network bottlenecks, changing the bonding mode or adding more NIC ports should alleviate the problem.