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
What affects the performance of a media server (MSDP)?
NetBackup 52xx appliance as the dedicated MSDP media server is the most common type of deployment. In this kind of scenario there are many factors that influence performance of the media server:
There are two distinctive types of deduplication scenarios that can be major performance differentiators:
NetBackup Client deduplication
In this scenario NetBackup client does part of the deduplication work. NetBackup Client will process backup data with the integrated deduplication plug-in (segments data and creates fingerprints) and send generated fingerprints to the NetBackup appliance for database lookup. This activity reduces the workload on the appliance and reduces the amount of data sent over the LAN from the NetBackup Client to NetBackup Appliance while creating minimal load on the client.
NetBackup Media Server deduplication
Media server-based deduplication places far greater workload on the appliance than the client-based deduplication since server processor is performing fingerprinting operations as well. Media server deduplication is a resource-intensive workload and running other concurrent operations that are resource-intensive will affect performance significantly. The appliance CPU cores play a primary role in the performance followed by RAM and disk I/O.
Table: Parameters influencing the performance of a media server
Which are the process executed for this role? | Which are the resources used / affected due to the process? | How NetBackup 52xx help to optimally perform these processes? | Comments |
|---|---|---|---|
In both types of deduplication scenarios the simplified workflow of standard deduplication load consists of the following tasks:
| Deduplication as described places strain on the system resources
| NetBackup 5220 Backup Appliance with its Intel Xeon quad core CPU and NetBackup 5230 with its latest generation Intel Xeon hexacore (six cores) CPU's provide powerful processing capabilities. NetBackup 5240 with its Intel Xeon CPUs with eight cores provide powerful processing capabilities. | To avoid resource congestion, ensure that when rehydration of data takes place no other concurrent operations run in parallel. During POC planning, the amount of client data has to be considered to not fill up the appliance file system and subsequently reduce both the backup and restore performance. All major subsystems of the appliance that are CPU, RAM, and Disk play an important role when it comes to deduplication performance. Running client-based deduplication which is lighter on the CPU than media server deduplication is a good practice, however careful consideration has to be taken to avoid running out of free memory. Note: In some specific cases there is a possibility that Client side deduplication performs slower than Media server deduplication. One such rare example is, backup of SQL Server transaction logs on the underpowered SQL Server. These cases are rare but possible and they are mentioned in the context of the exception that proves the rule. |
Scheduled rebasing According to a predetermined schedule, once a day, rebasing is run to group segments from the same backup together on the disk to improve the restore performance. | Operation like rebasing has a very positive effect on performance, backup image segments are grouped together on the disk which improves disk I/O throughput. | It is important to keep in mind that file system performance will degrade as free space approaches 100 % utilization. The watermark level is 90% utilization. | |
Restore Restore operation requires full rehydration of data which is the most resource intensive process on the NetBackup MSDP. | NetBackup 52xx backup appliance can restore data using multiple restore streams. | ||
Tape out from MSDP | Tape Out operation is very resource-intensive operation and requires full rehydration of the backup image. Performance of the tape out operation is limited by how tape drives handle multiple streams. Unlike restore operations that can benefit from appliance performance with multiple concurrent restore streams, tape drives can handle only one stream per tape drive thus limiting tape out performance. | Limit the number of I/O streams to the recommended value of 96. This can be done in the properties of storage unit under Max I/O streams text box. | |
CRQP (Content Router Queue Processing) It is one of the regular maintenance operations on MSDP that processes fingerprint database (CRDB) transaction logs (tlogs). This operation is necessary for the maintenance of the deduplication storage pool and is scheduled to run twice a day. | During CRQP activity there is a hit on the disk I/O and CPU/RAM resources in the range of 10% - 20% depending on the amount of tlogs to process and this has to be accounted for when planning for high performance tasks that will run concurrently with CRQP.
Details of the CRQP activity can be monitored through spooled log:
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Initial Optimized Duplication | Initial Optimized Duplication is an resource-intensive process and places a stress on the operating system. This severely affects the deduplication performance if executed concurrently with the backup. |
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