NetBackup™ Backup Planning and Performance Tuning Guide
- NetBackup capacity planning
- Primary server configuration guidelines
- Size guidance for the NetBackup primary server and domain
- Factors that limit job scheduling
- More than one backup job per second
- Stagger the submission of jobs for better load distribution
- NetBackup job delays
- Selection of storage units: performance considerations
- About file system capacity and NetBackup performance
- About the primary server NetBackup catalog
- Guidelines for managing the primary server NetBackup catalog
- Adjusting the batch size for sending metadata to the NetBackup catalog
- Methods for managing the catalog size
- Performance guidelines for NetBackup policies
- Legacy error log fields
- Media server configuration guidelines
- NetBackup hardware design and tuning considerations
- About NetBackup Media Server Deduplication (MSDP)
- Data segmentation
- Fingerprint lookup for deduplication
- Predictive and sampling cache scheme
- Data store
- Space reclamation
- System resource usage and tuning considerations
- Memory considerations
- I/O considerations
- Network considerations
- CPU considerations
- OS tuning considerations
- MSDP tuning considerations
- MSDP sizing considerations
- Cloud tier sizing and performance
- Accelerator performance considerations
- Media configuration guidelines
- About dedicated versus shared backup environments
- Suggestions for NetBackup media pools
- Disk versus tape: performance considerations
- NetBackup media not available
- About the threshold for media errors
- Adjusting the media_error_threshold
- About tape I/O error handling
- About NetBackup media manager tape drive selection
- How to identify performance bottlenecks
- Best practices
- Best practices: NetBackup SAN Client
- Best practices: NetBackup AdvancedDisk
- Best practices: Disk pool configuration - setting concurrent jobs and maximum I/O streams
- Best practices: About disk staging and NetBackup performance
- Best practices: Supported tape drive technologies for NetBackup
- Best practices: NetBackup tape drive cleaning
- Best practices: NetBackup data recovery methods
- Best practices: Suggestions for disaster recovery planning
- Best practices: NetBackup naming conventions
- Best practices: NetBackup duplication
- Best practices: NetBackup deduplication
- Best practices: Universal shares
- NetBackup for VMware sizing and best practices
- Best practices: Storage lifecycle policies (SLPs)
- Best practices: NetBackup NAS-Data-Protection (D-NAS)
- Best practices: NetBackup for Nutanix AHV
- Best practices: NetBackup Sybase database
- Best practices: Avoiding media server resource bottlenecks with Oracle VLDB backups
- Best practices: Avoiding media server resource bottlenecks with MSDPLB+ prefix policy
- Best practices: Cloud deployment considerations
- Measuring Performance
- Measuring NetBackup performance: overview
- How to control system variables for consistent testing conditions
- Running a performance test without interference from other jobs
- About evaluating NetBackup performance
- Evaluating NetBackup performance through the Activity Monitor
- Evaluating NetBackup performance through the All Log Entries report
- Table of NetBackup All Log Entries report
- Evaluating system components
- About measuring performance independent of tape or disk output
- Measuring performance with bpbkar
- Bypassing disk performance with the SKIP_DISK_WRITES touch file
- Measuring performance with the GEN_DATA directive (Linux/UNIX)
- Monitoring Linux/UNIX CPU load
- Monitoring Linux/UNIX memory use
- Monitoring Linux/UNIX disk load
- Monitoring Linux/UNIX network traffic
- Monitoring Linux/Unix system resource usage with dstat
- About the Windows Performance Monitor
- Monitoring Windows CPU load
- Monitoring Windows memory use
- Monitoring Windows disk load
- Increasing disk performance
- Tuning the NetBackup data transfer path
- About the NetBackup data transfer path
- About tuning the data transfer path
- Tuning suggestions for the NetBackup data transfer path
- NetBackup client performance in the data transfer path
- NetBackup network performance in the data transfer path
- NetBackup server performance in the data transfer path
- About shared memory (number and size of data buffers)
- Default number of shared data buffers
- Default size of shared data buffers
- Amount of shared memory required by NetBackup
- How to change the number of shared data buffers
- Notes on number data buffers files
- How to change the size of shared data buffers
- Notes on size data buffer files
- Size values for shared data buffers
- Note on shared memory and NetBackup for NDMP
- Recommended shared memory settings
- Recommended number of data buffers for SAN Client and FT media server
- Testing changes made to shared memory
- About NetBackup wait and delay counters
- Changing parent and child delay values for NetBackup
- About the communication between NetBackup client and media server
- Processes used in NetBackup client-server communication
- Roles of processes during backup and restore
- Finding wait and delay counter values
- Note on log file creation
- About tunable parameters reported in the bptm log
- Example of using wait and delay counter values
- Issues uncovered by wait and delay counter values
- Estimating the effect of multiple copies on backup performance
- Effect of fragment size on NetBackup restores
- Other NetBackup restore performance issues
- About shared memory (number and size of data buffers)
- NetBackup storage device performance in the data transfer path
- Tuning other NetBackup components
- When to use multiplexing and multiple data streams
- Effects of multiplexing and multistreaming on backup and restore
- How to improve NetBackup resource allocation
- Encryption and NetBackup performance
- Compression and NetBackup performance
- How to enable NetBackup compression
- Effect of encryption plus compression on NetBackup performance
- Information on NetBackup Java performance improvements
- Information on NetBackup Vault
- Fast recovery with Bare Metal Restore
- How to improve performance when backing up many small files
- How to improve FlashBackup performance
- Veritas NetBackup OpsCenter
- Tuning disk I/O performance
NetBackup job delays
NetBackup jobs may be delayed for a variety of reasons. Common delays that may occur, and in some cases suggests possible remedies, are described below..
The NetBackup Policy Execution Manager (nbpem) may not begin a backup at exactly the time a backup policy's schedule window opens. This delay can happen when you define a schedule or modify an existing schedule with a window start time close to the current time.
For instance, suppose that you create a schedule at 5:50 P.M., and specify that at 6:00 P.M. backups should start. You complete the policy definition at 5:55 P.M. At 6:00 P.M., you expect to see a backup job for the policy start, but it does not. Instead, the job takes another several minutes to start.
The explanation is the following: NetBackup receives and queues policy change events as they happen, but processes them periodically as configured in the Policy Update Interval setting. (The Policy Update Interval is set under Host Properties > Primary Server > Properties > Global Settings. The default is 10 minutes.) The backup does not start until the first time NetBackup processes policy changes after the policy definition is completed at 5:55 P.M. NetBackup may not process the changes until 6:05 P.M. For each policy change, NetBackup determines what needs to be done and updates its work list accordingly.
Note:
For any one client, there is a limit of starting only one job per second . However, multiple jobs from different clients can be started within the same second. Depending on the configuration involved, significantly more backup jobs can be started within any fixed time period, which may change the performance behavior of the system. In some environments, you may need to change some configuration settings to achieve the optimum performance behavior.
If jobs are queued and only one job runs at a time, use the State Details column in the Activity Monitor to see the reason for the job being queued.
If jobs are queued and only one job runs at a time, set one or more of the following to allow jobs to run simultaneously:
Select to limit the number of read and write streams (that is, jobs) for each volume in the disk pool. A job may read or write backup images. If you select this property, you also need to configure the number of streams to allow per volume. When the limit is reached, NetBackup chooses another volume for write operations, if available. If not available, NetBackup queues jobs until a volume is available. In a product like Netbackup Flexible Scale (NBFS), this property is unselected by default. (that is, no limit).
Schedule attribute (should be greater than 1).
The general recommendation is to start with a value of 4 and gradually increase it until you find an acceptable balance for both backup and restores. See Media multiplexing (schedule attribute) In the NetBackup Administrator's Guide, Volume 1, for more information on Media multiplexing
Note:
Keep in mind that increasing this value may affect restore times. More information is available:
See How fragment size affects restore of a multiplexed image on tape.
Check the following storage unit properties:
Is the storage unit enabled to use multiple tape drives ()? If you want to increase this value, remember to set it to fewer than the number of tape drives available to this storage unit. Otherwise, restores and other non-backup activities cannot run while backups to the storage unit are running.
Is the storage unit enabled for multiplexing ()? You can write a maximum of 32 jobs to one tape at the same time.
Note:
Values greater than 4 may actually decrease overall performance because they may reduce restore speeds. More information is available:
See How fragment size affects restore of a multiplexed image on tape.
Note:
Be sure to check with the disk storage manufacturers for recommendations about your disk storage units.
For example, you can run multiple jobs to a single storage unit if you have multiple drives. (Maximum concurrent write drives set to greater than 1.) Or, you can set up multiplexing to a single drive if Maximum streams per drive is set to greater than 1. If both Maximum concurrent write drives and Maximum streams per drive are greater than 1: you can run multiple streams to multiple drives, assuming that Maximum jobs per client is set high enough.
Note:
All storage units that reference a specific MSDP pool have a maximum concurrent jobs setting. The total number of concurrent jobs for all storage units accessing a single MSDP pool should be approximately 10% less than the maximum number of I/O streams on the disk pool. This allows for secondary operations, like replications and duplications, as well as restores to be executed even during busy backup windows.
Tape jobs become active as soon as the resources are allocated.
NetBackup makes the tape jobs active as follows:
The NetBackup Job Manager (nbjm) requests resources from the NetBackup Resource Broker (nbrb) for the job.
nbrb allocates the resources and gives the resources to nbjm.
nbjm starts bpbrm which in turn starts bptm.
The job fails if no other storage units are usable, in any of the following circumstances:
If the media in a storage unit are not configured or are unusable (such as expired)
The maximum mounts setting was exceeded
The wrong pool was selected
If media are unavailable, consider the following:
Add new media
Or change the media configuration to make media available (such as changing the volume pool or the maximum mounts).
If the media in a storage unit are usable but are busy, the job is queued. In the NetBackup Activity Monitor, the "State Details" column indicates why the job is queued, such as "media are in use." (The same information is available in the Job Details display. Right-click on the job and select "Details.") If the media are in use, the media eventually stop being used and the job runs.
A job may be queued by the NetBackup Job Manager (nbjm) if the media server is not available. The job is not queued because of communication timeouts, but because EMM knows that the media server is down and the NetBackup Resource Broker (nbrb) queues the request to be retried later.
If no other media servers are available, EMM queues the job under the following circumstances:
The Activity Monitor should display the reason for the job queuing, such as "media server is offline." Once the media server is online again in EMM, the job starts. In the meantime, if other media servers are available, the job runs on another media server.
If a media server is not configured in EMM, regardless of the physical state of the media server, EMM does not select that media server for use. If no other media servers are available, the job fails.
To permanently remove a media server from the system, consult the "Decommissioning a media server" section in the NetBackup Administrator's Guide, Volume I.