Veritas InfoScale™ 8.0.2 Replication Administrator's Guide - Linux
- Section I. Getting started with Volume Replicator
- Introducing Volume Replicator
- Understanding how Volume Replicator works
- How VVR processes application writes
- How VVR uses kernel buffers for replication
- How data flows in VVR asynchronous mode
- About secondary logging enabled asynchronous mode
- About bulk transfer with secondary logging
- How data flows in VVR asynchronous mode with secondary logging
- How data flows in VVR synchronous mode
- How data flows in VVR adaptive synchronous mode
- How data flows in an RDS containing multiple Secondary hosts
- Replication in a shared disk group environment
- Assigning a slave node as a logowner
- Understanding how VVR logs writes to the SRL
- Understanding Storage Checkpoints
- Volume sets in VVR
- Changing membership of an RVG and a volume set
- Using SmartTier with VVR
- Cross-platform Data Sharing in VVR
- Understanding the VVR snapshot feature
- About VVR compression
- Understanding data encryption over the wire
- Planning and configuring replication
- Introduction to planning and configuring replication
- Before you begin configuring
- Choosing the mode of volume replication
- Choosing latency and SRL protection
- Planning the network
- Sizing the SRL
- Choosing the type of DCM logging
- Best practices for setting up replication
- How the agents for hybrid applications work
- Pre-requisites to enable data over wire encryption
- Enabling Data Change Object (DCO) for SRL Volumes
- Understanding replication settings for a Secondary
- Configuring VVR in a VCS environment
- Overview of how to configure VVR in a VCS environment
- Configuring VVR with virtual hostname to map with multiple IPs (Stretched cluster support)
- Using the primary-elect feature to choose the primary site after a site disaster or network disruption
- Requirements for configuring VVR in a VCS environment
- Generic VVR setup in a VCS environment
- Example VVR configuration in a VCS environment
- Example RVG configuration for a failover application
- Example RVG configuration for a parallel application
- Example setting up VVR in a VCS environment
- Configuring the agents for a bunker replication configuration
- Administering VCS service groups
- Section II. Setting up and administering VVR
- Setting up replication
- About configuring VVR replication
- Enabling security certificate
- Setting up the certificate authority (CA) certificates in /etc/vx/vvr/cacert.pem
- Creating a Replicated Data Set
- Creating a Primary RVG of an RDS
- Adding a Secondary to an RDS
- Changing the replication settings for a Secondary
- Configuring adaptive synchronous replication
- Synchronizing the Secondary and starting replication
- Starting replication when the data volumes are zero initialized
- Starting replication over the wire when data volumes are encrypted
- Setting up replication with different sector-sized disks
- Displaying configuration information
- Displaying RVG and RDS information
- Displaying information about data volumes and volume sets
- Displaying information about Secondaries
- Displaying a list of Storage Checkpoints
- Displaying statistics with the vrstat display commands
- Displaying the consolidated statistics
- Displaying the RLINK information for all the hosts in the RDS
- Displaying information about all the data volumes for all the hosts in the RDS
- Displaying information about the SRL volumes for all the hosts in the RDS
- Displaying information about the memory tunable parameters for all the hosts in the RDS
- Determining VVR network bandwidth usage and compression ratio
- Collecting consolidated statistics of the VVR components
- Displaying network performance data
- VVR event notification
- Administering Volume Replicator
- Administering data volumes
- Associating a volume to a Replicated Data Set
- Associating a volume set to an RDS
- Associating a Data Change Map to a data volume in DCO
- Associating a Data Change Map to a data volume as a log plex
- Resizing a data volume in a Replicated Data Set
- Renaming a data volume in a Replicated Data Set
- Dissociating a data volume from its Replicated Data Set
- Mapping the name of a Secondary data volume to a differently named Primary data volume
- Mapping disk groups
- Administering the SRL
- Protecting from SRL overflow
- Incrementally synchronizing the Secondary after SRL overflow
- SRL overflow protection with DCM - flags and definitions
- Prerequisite for incrementally synchronizing the Secondary
- Breaking off mirrors before incremental synchronization
- Example - Resynchronizing the Secondary using break off mirrors
- Example - Recreating volumes if a disaster occurs during resynchronization
- Notes on using incremental synchronization on SRL overflow
- Changing the size of the SRL on the Primary and the Secondary
- Decreasing the size of the SRL on the Primary
- Administering replication
- Administering the Replicated Data Set
- Administering Storage Checkpoints
- Creating RVG snapshots
- Using the instant snapshot feature
- About instant full snapshots
- Prerequisites for creating instant full snapshots
- Creating snapshot volumes for data volumes in an RVG
- Preparing the volumes prior to using the instant snapshot feature
- Freezing or pausing replication prior to taking a snapshot
- Creating instant full snapshots
- Unfreezing or resuming replication after taking a snapshot
- About instant space-optimized snapshots
- Preparing the RVG volumes for snapshot operation
- Creating the cache object for instant space-optimized snapshots
- Freezing or pausing replication prior to creating an instant space-optimized snapshot
- Creating instant space-optimized snapshots
- Unfreezing or resuming replication after taking an instant space-optimized snapshot
- About instant plex-breakoff snapshots
- Administering snapshots
- Using the traditional snapshot feature
- Using Veritas Volume Manager FastResync
- Verifying the DR readiness of a VVR setup
- Backing up the Secondary
- Administering data volumes
- Using VVR for off-host processing
- Transferring the Primary role
- About transferring the Primary role
- Migrating the Primary
- About taking over from an original Primary
- Failing back to the original Primary
- About choosing the Primary site after a site disaster or network disruption
- Application availability in the case of a network disruption
- Configuring VCS global clustering so you can choose the Primary site
- Choosing the Primary site after a site disaster or network disruption
- Troubleshooting the primary-elect feature
- Primary-elect configuration limitations
- Replication using a bunker site
- Introduction to replication using a bunker site
- Sample bunker configuration
- Setting up replication using a bunker site
- Administering replication using a bunker site
- Using a bunker for disaster recovery
- Replication using a bunker site in a VCS environment
- Removing a bunker
- About bunker commands
- Troubleshooting VVR
- Recovery from RLINK connect problems
- Recovery from configuration errors
- Errors during an RLINK attach
- Errors during modification of an RVG
- Recovery on the Primary or Secondary
- About recovery from a Primary-host crash
- Recovering from Primary data volume error
- Primary SRL volume error cleanup and restart
- Primary SRL volume error at reboot
- Primary SRL volume overflow recovery
- Primary SRL header error cleanup and recovery
- Secondary data volume error cleanup and recovery
- Secondary SRL volume error cleanup and recovery
- Secondary SRL header error cleanup and recovery
- Secondary SRL header error at reboot
- Tuning replication performance
- Overview of replication tuning
- SRL layout
- Tuning Volume Replicator
- VVR buffer space
- Write buffer space on the Primary
- Readback buffer space on the Primary
- Buffer space on the Secondary
- Tunable parameters for the VVR buffer spaces
- Tunable parameters for the write buffer space on the Primary in a private disk group
- Tunable parameter for the readback buffer space
- Tunable parameters for the buffer space on the Primary in a shared disk group
- Tunable parameters for the buffer space on the Secondary
- DCM replay block size
- Heartbeat timeout
- Memory chunk size
- UDP replication tuning
- Tuning the number of TCP connections
- Message slots on the Secondary
- VVR and network address translation firewall
- Tuning VVR compression
- VVR buffer space
- Setting up replication
- Section III. Getting started with File Replicator
- Introducing File Replicator
- Administering File Replicator
- About vfradmin utility
- Starting the vxfstaskd and vxfsrepld file replication daemons
- Protecting a target file system
- Creating a file replication job
- Creating a consistency group
- Managing a file replication job
- Displaying file replication job information
- Modifying a file replication job
- Modifying a consistency group
- Working with pattern lists
- Deleting a file replication job
- Deleting a consistency group
- Migrating VFR to support IPv6/dual-stack
- Performing a VFR switchover
- Performing a VFR failover after a disaster
- Recovering a failed site if the failed source node comes up again
- Recovering a failed site if a new node is assigned as the target
- Section IV. Analyzing your environment with Volume Replicator Advisor
- Introducing Volume Replicator Advisor (VRAdvisor)
- Collecting the sample of data
- About collecting the sample of data
- Collecting the sample of data on UNIX
- Collecting the sample of data on Windows
- Analyzing the sample of data
- About analyzing the sample of data
- Launching the VRAdvisor wizard
- Analyzing the collected data
- Understanding the results of the analysis
- Viewing the analysis results
- Recalculating the analysis results
- Applying different parameters to the existing sample of data
- Performing What-if analysis
- Calculating the SRL Size for a specified Network Bandwidth and Outage
- Calculating the Network Bandwidth for data loss specified in bytes
- Calculating the Network Bandwidth for data loss specified in time duration
- Calculating the Network Bandwidth for Bunker and RTO
- Changing the value ranges on the slider bar
- Recording and viewing the results
- Installing Volume Replicator Advisor (VRAdvisor)
- Section V. VVR reference
- Appendix A. VVR command reference
- Appendix B. Using the In-band Control Messaging utility vxibc and the IBC programming API
- About the IBC messaging utility vxibc
- In-band Control Messaging overview
- Using the IBC messaging command-line utility
- Registering an application name
- Displaying the registered application name for an RVG
- Receiving an IBC message
- Sending an IBC message
- Unfreezing the Secondary RVG
- Unregistering an application name
- Receiving and processing an IBC message using a single command
- Sending and processing an IBC message using a single command
- Examples - Off-host processing
- Example 1 - Decision support using the traditional snapshot feature and the vxibc utility
- Example 2 - Backing up using the snapshot feature and the vxibc utility
- Example 3 - Trial failover using the snapshot feature
- Example 4 - Decision support using the instant full snapshot feature and the vxibc utility
- In-band Control Messaging API
- Appendix C. Volume Replicator object states
- Appendix D. Alternate methods for synchronizing the Secondary
- Using the full synchronization feature
- Using block-level backup and Storage Checkpoint
- Using the Disk Group Split and Join feature
- Using difference-based synchronization
- Examples for setting up a simple Volume Replicator configuration
- Creating a Replicated Data Set for the examples
- Example for setting up replication using full synchronization
- Example for setting up replication using block-level backup and checkpointing
- Example for setting up replication using Disk Group Split and Join
- Example for setting up replication using differences-based synchronization
- Example for setting up replication when data volumes are initialized with zeroes
- Appendix E. Migrating VVR from IPv4 to IPv6
- Migrating VVR to support IPv6 or dual stack
- Overview of VVR migration from IPv4 to IPv6
- About migrating to IPv6 when VCS global clustering and VVR agents are not configured
- About migrating to IPv6 when VCS global clustering and VVR agents are configured
- Understanding the current IPv4 configuration when VCS global clustering and VVR agents are configured
- Migration prerequisites when VCS global clustering and VVR agents are configured
- Migrating to IPv6 when VCS global clustering and VVR agents are configured
- Migrating the VCS global clustering service group to IPv6 when VCS global clustering and VVR agents are configured
- Adding IP and NIC resources for IPv6 addresses in the RVG agent group when VCS global clustering and VVR agents are configured
- Migrating VVR RLINKs from IPv4 to IPv6 when VCS global clustering and VVR agents are configured
- Removing the IPv4 resources from the VCS configuration when VCS global clustering and VVR agents are configured
- About migrating to IPv6 when VCS global clustering and VVR agents are configured in the presence of a bunker
- Understanding the current IPv4 configuration when VCS global clustering and VVR agents are configured in the presence of a bunker
- Migration prerequisites when VCS global clustering and VVR agents are configured in the presence of a bunker
- Migrating to IPv6 when VCS global clustering and VVR agents are configured in the presence of a bunker
- Migrating the VCS global clustering service group to IPv6 when VCS global clustering and VVR agents are configured in the presence of a bunker
- Adding the IP and NIC resources for IPv6 addresses in the RVG agent group when VCS global clustering and VVR agents are configured in the presence of a bunker
- Migrating VVR RLINKs from IPv4 to IPv6 when VCS global clustering and VVR agents are configured in the presence of a bunker
- Removing the IPv4 resources from the VCS configuration when VCS global clustering and VVR agents are configured in the presence of a bunker
- Appendix F. Sample main.cf files
Using the automatic synchronization feature
The Automatic Synchronization feature enables you to transfer the data on the Primary to the Secondary over the network. You can synchronize the Secondary using automatic synchronization either when the application is active or inactive.
The Automatic Synchronization procedure transfers data in the Primary data volumes to the Secondary by reading the Primary data volumes from start to finish and sending the data to the Secondary.
Note:
Automatic Synchronization does not maintain the order of writes; therefore, the Secondary is inconsistent until the process is complete.
The Secondary becomes consistent after the automatic synchronization completes. To use Automatic Synchronization successfully, the network must be sized appropriately. Note that the synchronization will complete only if the Primary receives writes at a lesser rate than they can be sent to the Secondary. If the Primary receives writes at a faster rate than they can be sent to the Secondary, the synchronization might never complete, especially if the writes are dispersed widely in the volume.
This feature enables you to synchronize multiple Secondary hosts at the same time. When performing automatic synchronization to multiple Secondary hosts, synchronization proceeds at the rate of the slowest network.
VVR pauses synchronization if the Secondary fails or the network disconnects. If the Primary fails while synchronization is in progress, the synchronization continues from the point at which it had stopped when the Primary recovers.
Prerequisite for using Automatic Synchronization
Each data volume in the Primary RVG must have a DCM associated to it. If data volumes do not have DCMs, an attempt to automatically synchronize a Secondary fails.
The vradmin startrep command when used with the option -a enables you to start replication and automatically synchronize the Secondary data volumes with the Primary data volumes in an RDS; it brings the Secondary data volumes up-to-date with the Primary data volumes. You can use this command to synchronize the Secondary when the data volumes contain data and when the application is active or inactive. Replication to another Secondary can be started only after this automatic synchronization completes.
The vradmin startrep command can be issued from any host in the RDS. To check the status and progress of the automatic synchronization, use the vxrlink status command on the Primary RLINK.
See Displaying the status of a Secondary.
To synchronize the Secondary and start replication using automatic synchronization, issue the following command:
# vradmin -g diskgroup -a startrep local_rvgname sec_hostname
The argument local_rvgname is the name of the RVG on the local host and represents its RDS.
The argument sec_hostname is the name of the Secondary host displayed in the output of the vradmin printrvg command. If the RDS contains only one Secondary, the sec_hostname is optional.
Example - Using the Automatic Synchronization Feature
In this example, the data volumes in the Primary RVG hr_rvg on host seattle contain valid data and the application is active. To start replication and synchronize the Secondary RVG hr_rvg on host london, issue the following command:
# vradmin -g hrdg -a startrep hr_rvg london