InfoScale™ 9.0 Replication Administrator's Guide - AIX
- 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 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
- 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
- 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
- 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
- Configuring and administering VVR using System Management Interface Tool
- About SMIT for VVR
- Accessing Volume Replicator interface in SMIT
- Setting up a simple Volume Replicator configuration using SMIT
- Displaying configuration information using SMIT
- Administering Volume Replicator using SMIT
- Pausing replication to a Secondary using SMIT
- Resuming replication to a Secondary using SMIT
- Resynchronizing a Secondary using SMIT
- Taking traditional snapshot of data volumes of an RVG using SMIT
- Taking instant snapshot of data volumes of an RVG using SMIT
- Snapback of data volumes of an RVG using SMIT
- Associating a volume to a Replicated Data Set using SMIT
- Dissociating a data volume from a Replicated Data Set using SMIT
- Removing a Secondary from a Replicated Data Set using SMIT
- Removing a Primary from an RDS using SMIT
- Stopping replication to a Secondary using SMIT
- Transferring the Primary role using SMIT
- 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. 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 IV. 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
Modifying the failover service group used for replication to IPv6
On the Primary site, in the existing failover service group created for the IPv4 virtual IP, create an IP resource and/or NIC resource for the virtual IPv6 address. In the following example, the service group is VVRGRP.
To modify the failover service group used for replication to IPv6
- Enable write operations on the VCS configuration. Enter the following:
# haconf -makerw
- Add the NIC resource for the IPv6 address and configure the related attributes:
# hares -add nicres_v6 NIC VVRGRP # hares -modify nicres_v6 Device en1 # hares -modify nicres_v6 Enabled 1 # hares -probe nicres_v6 -sys node1 # hares -probe nicres_v6 -sys node2
- Add the IP resource for the IPv6 address and configure the necessary attributes.
# hares -add ipres_v6 IP VVRGRP # hares -modify ipres_v6 Device en1 # hares -modify ipres_v6 \ Address fd4b:454e:205a:111:211:43ff:feaa:af71 # hares -modify ipres_v6 Enabled 1 # hares -modify ipres_v6 PrefixLen 64 # hares -probe ipres_v6 -sys node1 # hares -probe ipres_v6 -sys node2 # hares -online ipres_v6 -sys node1
In the example above, the new IP resource ipres_v6 is configured for the virtual IPv6 address.
Note:
If you configure the IPv6 address on the same NIC that is used for IPv4, you do not need to create a new NIC resource. Instead, use the existing NIC resource and link the new IP resource to it. If you configure the IPv6 address on a separate interface, create a new NIC resource (nicres_v6) for the IPv6 interface.
- Link the IP resource to the NIC resource, Enter the following:
# hares -link ipres_v6 nicres_v6
- Save your configuration changes. Enter the following:
# haconf -dump -makero
- Repeat step 1 to 5 on the Secondary site.
The virtual IP will be different on each site.
Note:
Do not stop VCS; do not modify the existing service group in the main.cf file. These changes affect replication between the sites because the service group will go offline.
After you save the configuration, the service group (VVRGRP) has the following settings:
The state of resources after configuring the virtual IPv6 address:
# hares -state | grep -i res Resource Attribute System Value ipres State swax25 ONLINE ipres State swax27 OFFLINE ipres_v6 State swax25 ONLINE ipres_v6 State swax27 OFFLINE nicres State swax25 ONLINE nicres State swax27 ONLINE nicres_v6 State swax25 ONLINE nicres_v6 State swax27 ONLINE
The state of the failover service group (VVRGRP):
# hastatus -summ | grep -i vvr B VVRGRP swax25 Y N ONLINE B VVRGRP swax27 Y N OFFLINE
The updated contents of
main.cffile after adding new resources:group VVRGRP ( SystemList = { swax25 = 0, swax27 = 1 } AutoStartList = { swax25 } ) IP ipres ( Device = en0 Address = "10.209.87.186" NetMask = "255.255.252.0" ) IP ipres_v6 ( Device = en1 Address = "fd4b:454e:205a:111:211:43ff:feaa:af71" PrefixLen = 64 ) NIC nicres ( Enabled = 1 Device = en0 ) NIC nicres_v6 ( Enabled = 1 Device = en1 ) ipres requires nicres ipres_v6 requires nicres_v6 // resource dependency tree // // group VVRGRP // { // IP ipres // { // NIC nicres // } // IP ipres_v6 // { // NIC nicres_v6 // } // }After you modify the service group VVRGRP, the output of the ifconfig command is as follows:
# ifconfig -a en0: flags=1e080863,c0<UP,BROADCAST,NOTRAILERS,RUNNING,SIMPLEX,MULTICAST,GROUPRT,64BIT, CHECKSUM_OFFLOAD(ACTIVE),LARGESEND,CHAIN> inet 10.209.145.135 netmask 0xfffffc00 broadcast 10.209.147.255 inet 10.209.87.186 netmask 0xff000000 broadcast 10.255.255.255 tcp_sendspace 131072 tcp_recvspace 65536 rfc1323 0 en1: flags=1e080863,c0<UP,BROADCAST,NOTRAILERS,RUNNING,SIMPLEX,MULTICAST,GROUPRT,64BIT, CHECKSUM_OFFLOAD(ACTIVE),LARGESEND,CHAIN> inet6 fd4b:454e:205a:111:211:43ff:feaa:af71/0 lo0: flags=e08084b<UP,BROADCAST,LOOPBACK,RUNNING,SIMPLEX,MULTICAST,GROUPRT,64BIT> inet 127.0.0.1 netmask 0xff000000 broadcast 127.255.255.255 inet6 ::1/0 tcp_sendspace 131072 tcp_recvspace 131072 rfc1323 1
In this example, the virtual IPv4 address is en0: 10.209.87.186 and the virtual IPv6 address is en1: fd4b:454e:205a:111:211:43ff:feaa:af71.
Note:
Replication continues to use the virtual IPv4 address. The virtual IPv6 address is successfully configured without affecting the existing VVR replication.
Because both the virtual IPv4 and IPv6 addresses are online, you can migrate the Primary and Secondary VVR sites from the IPv4 network to the IPv6 network without disrupting the replication between the sites.