Veritas NetBackup™ Administrator's Guide, Volume I
- Section I. About NetBackup
- Section II. Configuring hosts
- Configuring Host Properties
- About the NetBackup Host Properties
- Access Control properties
- Bandwidth properties
- Busy File Settings properties
- Client Attributes properties
- Client Settings properties for UNIX clients
- Client Settings properties for Windows clients
- Data Classification properties
- Default Job Priorities properties
- Encryption properties
- Exchange properties
- Exclude Lists properties
- Fibre Transport properties
- Firewall properties
- General Server properties
- Global Attributes properties
- Logging properties
- Login Banner Configuration properties
- Media properties
- Network Settings properties
- Port Ranges properties
- Preferred Network properties
- Resilient Network properties
- Restore Failover properties
- Retention Periods properties
- Scalable Storage properties
- Servers properties
- SharePoint properties
- SLP Parameters properties
- Throttle Bandwidth properties
- Universal Settings properties
- User Account Settings properties
- Configuration options for NetBackup servers
- PREFERRED_NETWORK option for NetBackup servers
- THROTTLE_BANDWIDTH option for NetBackup servers
- Configuration options for NetBackup clients
- IGNORE_XATTR option for NetBackup clients
- VXSS_NETWORK option for NetBackup clients
- Configuring server groups
- Configuring host credentials
- Managing media servers
- Configuring Host Properties
- Section III. Configuring storage
- Configuring disk storage
- Configuring robots and tape drives
- About configuring robots and tape drives in NetBackup
- Adding a robot to NetBackup manually
- Managing robots
- Adding a tape drive to NetBackup manually
- Adding a tape drive path
- Correlating tape drives and device files on UNIX hosts
- Managing tape drives
- Performing device diagnostics
- Configuring tape media
- About NetBackup volume pools
- About WORM media
- About adding volumes
- Configuring media settings
- Media settings options
- Media type (new media setting)
- Media settings options
- About barcodes
- Configuring barcode rules
- Configuring media ID generation rules
- Adding volumes by using the Actions menu
- Configuring media type mappings
- Managing volumes
- About exchanging a volume
- About frozen media
- About injecting and ejecting volumes
- About rescanning and updating barcodes
- About labeling NetBackup volumes
- About moving volumes
- About recycling a volume
- Managing volume pools
- Managing volume groups
- Inventorying robots
- About showing a robot's contents
- About updating the NetBackup volume configuration
- About the vmphyinv physical inventory utility
- Configuring storage units
- About the Storage utility
- Creating a storage unit
- About storage unit settings
- Absolute pathname to directory or absolute pathname to volume setting for storage units
- Maximum concurrent jobs storage unit setting
- Staging backups
- Creating a basic disk staging storage unit
- Configuring storage unit groups
- Section IV. Configuring storage lifecycle policies (SLPs)
- Configuring storage lifecycle policies
- Storage operations
- Index From Snapshot operation in an SLP
- Snapshot operation in an SLP
- Retention types for SLP operations
- Capacity managed retention type for SLP operations
- Storage lifecycle policy options
- Using a storage lifecycle policy to create multiple copies
- Storage lifecycle policy versions
- Section V. Configuring backups
- Creating backup policies
- Planning for policies
- Policy Attributes tab
- Policy storage (policy attribute)
- Policy volume pool (policy attribute)
- Take checkpoints every __ minutes (policy attribute)
- Backup Network Drives (policy attribute)
- Cross mount points (policy attribute)
- Encryption (policy attribute)
- Collect true image restore information (policy attribute) with and without move detection
- Use Accelerator (policy attribute)
- Enable optimized backup of Windows deduplicated volumes
- Use Replication Director (policy attributes)
- Schedule Attributes tab
- Type of backup (schedule attribute)
- Frequency (schedule attribute)
- Multiple copies (schedule attribute)
- Retention (schedule attribute)
- Media multiplexing (schedule attribute)
- Start Window tab
- Include Dates tab
- How open schedules affect calendar-based and frequency-based schedules
- About the Clients tab
- Backup Selections tab
- Adding backup selections to a policy
- Verifying the Backup Selections list
- Pathname rules for UNIX client backups
- About the directives on the Backup Selections list
- ALL_LOCAL_DRIVES directive
- Files that are excluded from backups by default
- Disaster Recovery tab
- Active Directory granular backups and recovery
- Synthetic backups
- Using the multiple copy synthetic backups method
- Protecting the NetBackup catalog
- Parts of the NetBackup catalog
- Protecting the NetBackup catalog
- Archiving the catalog and restoring from the catalog archive
- Estimating catalog space requirements
- About the NetBackup relational database
- About the NetBackup relational database (NBDB) installation
- Using the NetBackup Database Administration utility on Windows
- Using the NetBackup Database Administration utility on UNIX
- Post-installation tasks
- About backup and recovery procedures
- Managing backup images
- Creating backup policies
- Section VI. Deployment Management
- Deployment Management
- Adding or changing schedules in a deployment policy
- Deployment Management
- Section VII. Configuring replication
- About NetBackup replication
- About NetBackup Auto Image Replication
- Viewing the replication topology for Auto Image Replication
- About the storage lifecycle policies required for Auto Image Replication
- Removing or replacing replication relationships in an Auto Image Replication configuration
- About NetBackup replication
- Section VIII. Monitoring and reporting
- Monitoring NetBackup activity
- About the Jobs tab
- About the Daemons tab
- About the Processes tab
- About the Drives tab
- About the jobs database
- About pending requests and actions
- Reporting in NetBackup
- Using the Logging Assistant
- Monitoring NetBackup activity
- Section IX. Administering NetBackup
- Management topics
- Accessing a remote server
- Using the NetBackup Remote Administration Console
- Run-time configuration options for the NetBackup Administration Console
- About improving NetBackup performance
- About adjusting time zones in the NetBackup Administration console
- Alternate server restores
- About performing alternate server restores
- Managing client backups and restores
- About client-redirected restores
- Powering down and rebooting NetBackup servers
- About Granular Recovery Technology
- About configuring Services for Network File System (NFS) on Windows 2012, 2012 R2, or 2016
- About configuring Services for Network File System (NFS) on Windows 2008 and 2008 R2
Media multiplexing (schedule attribute)
The Media multiplexing attribute specifies the maximum number of jobs from the schedule that NetBackup can multiplex onto any one drive. Multiplexing sends concurrent backup jobs from one or several clients to a single drive and multiplexes the backups onto the media.
Specify a number from 1 through 32, where 1 specifies no multiplexing. Any changes take effect the next time a schedule runs.
Note:
Some policy types and some schedule types do not support media multiplexing. The option cannot be selected in those instances.
Caution:
For MS-SQL-Server policies, do not enable multiplexing for a schedule that is also configured to backup with multiple stripes. Restores fail when multiplexing is enabled for a schedule that uses more than one stripe.
To configure multiplexed backups, multiplexing must be indicated in both the storage unit (Maximum Streams Per Drive setting) and the schedule (Media Multiplexing setting) configuration. Regardless of the Media multiplexing setting, the maximum jobs that NetBackup starts never exceeds the Maximum Streams Per Drive value for the storage unit.
NetBackup multiplexing sends concurrent backups from one or several clients to a single storage device. NetBackup multiplexes the backups sequentially onto the media. Multiplexed and unmultiplexed backups can reside on the same volume. Separate volume pools or media IDs are not necessary.
Figure: Multiplexed backups shows the multiplexed flow of client data to a server.
Multiplexing is generally used to reduce the amount of time that is required to complete backups. The following table describes circumstances where performance improves by using multiplexing:
Table: Circumstances where multiplexing improves performance
Item | Description |
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Slow clients | Instances in which NetBackup uses software compression, which normally reduces client performance, are also improved. |
Multiple slow networks | The parallel data streams take advantage of whatever network capacity is available. |
Many short backups (for example, incremental backups) | In addition to providing parallel data streams, multiplexing reduces the time each job waits for a device to become available. Therefore, the storage device transfer rate is maximized. |
No special action is required to restore a multiplexed backup. NetBackup finds the media and restores the requested backup. Multiplexing reduces performance on restores because it uses extra time to read the images.
To reduce the effect of multiplexing on restore times, set the storage unit maximum fragment size to a value smaller than the largest allowed value. Also, on UNIX, enable fast-tape positioning (locate block), if it applies to the tape drives in use.
Consider the following configuration settings when using multiplexing.
Table: Properties and attributes that affect multiplexing
Item | Description | Where to find it |
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(policy attribute) | Limits the number of jobs that NetBackup performs concurrently when a policy is run. Set this attribute high enough to support the specified level of multiplexing. |
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(host property) | Limits the number of backup jobs that can run concurrently on any NetBackup client. This property is part of Global Attributes host properties. See Global Attributes properties. Usually, the client setting does not affect multiplexing. However, consider a case where jobs from different schedules on the same client go to the same storage unit. In this case, the maximum number of jobs that are permitted on the client is reached before the multiplexing limit is reached for the storage unit. When the maximum number of jobs on the client is reached, NetBackup cannot use the storage unit's full multiplexing capabilities. Select a value that is based on the ability of the central processing unit to handle parallel jobs. Because extra buffers are required, memory is also important. If the server cannot perform other tasks or runs out of memory or processes, reduce the Maximum streams per drive setting for the storage unit. To estimate the potential load that multiplexing can place on the central processing unit, consider the following limits:
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(host property) | Set the maximum number of jobs that are allowed on a specific client without affecting other clients. This property is part of Client Attributes host properties. |
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(host property) | Specifies how long the server waits for additional restore requests of files and raw partitions in a set of multiplexed images on the same tape. This property is part of General Server host properties. |
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(policy schedule attribute) | If the limit is reached for a drive, NetBackup sends jobs to other drives. When NetBackup multiplexes jobs, it continues to add jobs to a drive until the number of jobs on the drive matches the limit or the limit. |
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(storage unit setting) | NetBackup can add jobs from more than one schedule to a drive. When NetBackup multiplexes jobs, it continues to add jobs to a drive until the number of jobs on the drive matches the limit or the limit. |
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