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
Displaying consolidated replication status
The vradmin repstatus command displays the consolidated replication status of the specified Replicated Data Set (RDS). The vradmin repstatus command displays the following information about each RVG in the RDS:
Consolidated view of the RDS
Replication settings for all Secondary hosts in the RDS
Status of the data on each Secondary host in the RDS
Status of replication to each Secondary host in the RDS
To display consolidated replication information about an RDS:
# vradmin -g diskgroup [-l] repstatus local_rvgname
The argument local_rvgname is the name of the RVG on the local host. The local RVG name represents its RDS.
The option -l displays additional information, such as RLINK names, replication setting, compression mode, and so on. Similar to the vradmin -l printrvg command, the vradmin repstatus command also displays configuration errors in the RDS, if any.
Note:
If the vradmin repstatus command is run on a Secondary that has a few configuration errors or cannot reach the Primary, the output displays the status known to the Secondary before the above condition occurred and therefore might be out of date.
Example:
When the Primary is reachable from all the Secondary hosts and the vradmin repstatus command is run from any host:
# vradmin -g hrdg -l repstatus hr_rvg
Output resembles:
Replicated Data Set: hr_rvg Primary: Host name: seattle RVG name: hr_rvg DG name: hrdg RVG state: enabled for I/O Data volumes: 4 Vsets: 1 SRL name: hr_srl SRL size: 4.00 GB Total secondaries: 1 Secondary: Host name: london RVG name: hr_rvg DG name: hrdg Rlink from Primary: rlk_london_hr_rvg Rlink to Primary: rlk_seattle_hr_rvg Configured mode: asynchronous Latency protection: off SRL protection: autodcm Data status: inconsistent Replication status: resync in progress (smartsync autosync) Current mode: asynchronous Logging to: DCM (contains 169728 Kbytes) (autosync) Timestamp Information: N/A Bandwidth Limit: 30.00 Mbps Compression Mode: Off
Example:
When the Primary is unreachable from the Secondary hosts and the vradmin repstatus command is run from the Secondary host:
# vradmin -g hrdg -l repstatus hr_rvg
Output resembles:
VxVM VVR vradmin INFO V-5-52-1205 Primary is unreachable or RDS has configuration
error. Displayed status information is from Secondary and can be out-of-date.
Replicated Data Set: hr_rvg
Primary:
Host name: seattle <unreachable>
RVG name: hr_rvg
DG name: hrdg
RVG state: enabled for I/O
Data volumes: 4
Vsets: 1
SRL name: hr_srl
SRL size: 4.00 GB
Total secondaries: 1
Secondary:
Host name: london
RVG name: hr_rvg
DG name: hrdg
Rlink from Primary: rlk_london_hr_rvg
Rlink to Primary: rlk_seattle_hr_rvg
Configured mode: asynchronous
Latency protection: off
SRL protection: autodcm
Data status: consistent, up-to-date
Replication status: replicating (connected)
Current mode: asynchronous
Logging to: SRL (0 updates behind, last update ID 18533.0)
Timestamp Information: behind by 00:00:00 hours
Bandwidth Limit: 30.00 Mbps
Compression Mode: Off
Last Update on Primary: Oct 10 04:32:21
Secondary up-to-date as of: Oct 10 04:32:21
Config Errors:
seattle: Pri or Sec IP not available or vradmind not running,
stale informationThe following section describes the important fields displayed by the vradmin repstatus command. The values and meaning of each field are listed in tables:
: Displays the state of the Primary RVG. The following table lists the values for the RVG state field and their meanings.
acting_secondary
This Primary RVG is currently the acting Secondary as part of the fast failback process. Writes to the data volumes in this RVG are disabled independent of whether the RVG is started or stopped.
disabled for I/O
Primary RVG is disabled for I/O, that is, the RVG is stopped.
enabled for I/O
Primary RVG is enabled for I/O, that is, RVG is started.
needs recovery
State after an import or reboot.
The vxrvg recover rvg command clears this state.
passthru
The Primary RVG is in passthru mode because the Primary SRL is detached or missing.
: Shows the data status of this Secondary. The following table lists the values for the Data status field and their meanings:
consistent, behind
Secondary data is consistent but not up-to-date with the Primary data.
consistent, stale
The data on this Secondary is consistent. Replication to this Secondary has been stopped; the Primary RLINK is detached.
consistent, up-to-date
The Secondary data is consistent and is current or up-to-date with the Primary data. The Primary role can be migrated to this Secondary.
inconsistent
The data on the Secondary volumes is not consistent and the Secondary cannot take over.
needs recovery
State after an import or reboot.
The vxrlink recover command clears this state.
N/A
Current state of the Secondary data cannot be determined. This may occur because of a configuration error on this Secondary. For information about the state, use the vxprint -l rlink_name command on the Primary and Secondary.
: Displays the mode of replication, asynchronous or synchronous, that is being used to replicate data to the Secondary. This value can be different from the configured replication setting if the configured mode is synchronous=override.
: Displays the status of the replication to the Secondary. The following table lists the values for the Replication status field and their meanings:
Value
Meaning
logging to DCM
DCM is active for this Secondary, that is, new updates on Primary are tracked using DCM for this Secondary. The following information may be displayed:
needs dcm resynchronization - To continue replication, resynchronize the Secondary using DCM resynchronization.
See Incrementally synchronizing the Secondary after SRL overflow.
needs failback synchronization - To continue replication, start failback synchronization to this Secondary.
needs failback synchronization
This Primary RVG is acting as Secondary as part of the fast failback process. To continue replication, start failback resynchronization on the new Primary.
not replicating
Data is not being replicated to Secondary because Primary RLINK is in needs_recovery state.
primary needs_recovery - Primary RLINK in needs_recovery state and needs to be recovered before replication can resume.
paused by user
Replication to Secondary is paused because of some administrative action. This results in the following states:
primary paused - Primary RLINK is paused.
secondary paused - Secondary RLINK is paused.
paused due to error
Replication to Secondary is paused because of the following errors:
secondary config error - Secondary has some configuration error.
See Interpreting RLINK flag settings.
secondary log error - Secondary SRL has an I/O error.
paused due to network disconnection
Replication to Secondary is paused because of some network problem.
replicating
connected - Replication can take place if there are updates on the Primary data volumes
resync in progress
Resynchronization to the Secondary is in progress.
autosync - Resynchronization type is autosync.
dcm resynchronization - Resynchronization after an SRL overflow.
failback resynchronization - Resynchronization using failback logging.
smartsync - Resynchronization type is autosync using SmartMove.
resync paused by user
Resynchronization to Secondary is paused because of some administrative action. This results in the following states:
primary paused - Primary RLINK is paused.
secondary paused - Secondary RLINK is paused.
resync paused due to error
Resynchronization to Secondary is paused because of the following errors:
secondary config error - Secondary has some configuration error.
See Interpreting RLINK flag settings.
secondary log error - Secondary SRL has an I/O error.
resync paused due to network disconnection
Resynchronization to Secondary is paused because of some network problem.
stopped
Replication to Secondary is stopped because of the following:
Primary detached - Primary RLINK is detached.
Secondary detached - Secondary RLINK is detached.
N/A
The replication status cannot be determined. For information about the status, use the vxprint -l rlink_name command on the Primary and Secondary.
: Indicates whether updates for this Secondary are tracked on the Primary using the SRL or DCM. The following table lists the values for the Logging to field and their meanings:
Value
Meaning
DCM (contains xxx Kbytes) (log_type)
DCM is active (in use) for the replication to this Secondary. log_type can be autosync, failback logging, or SRL protection logging.
The yyy% value can sometimes reach beyond 100%. If synchronization is restarted and the DCM map is full, new incoming writes will cause the total yyy% to exceed 100%.
SRL (xxx Kbytes behind, yyy % full)
Updates to be transferred to Secondary are logged into the SRL and are currently occupying xxx Kbytes or yyy% of the SRL
SRL
SRL is used for logging. Check the Data status field for the status of the Secondary data.
If the vradmin repstatus command is run on a Secondary and the Secondary is disconnected from the Primary because of a configuration or network error, the Logging to field may show the following values:
Value
Meaning
DCM (log_type)
The last known information about logging type before the Secondary disconnected from the Primary is that it was logging to DCM.
SRL (xxx updates behind, last update ID yyy)
Before Secondary disconnected from the Primary, SRL was used for logging. Secondary was xxx updates behind the Primary, and the last update that was applied on the Secondary has update ID yyy. This information is similar to that displayed by the vxrlink updates command.
SRL (updates behind N/A)
Before Secondary disconnected from the Primary, SRL was used for logging. The number of updates this Secondary is behind with the Primary is not known.
These fields are the same as the output that is displayed for the vxrlink -T command.
Displays the mode of compression. The values are on or off.