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Veritas InfoScale™ 8.0.2 Replication Administrator's Guide - Linux

Last Published: 2023-07-20

Product(s): InfoScale & Storage Foundation (8.0.2)

Platform: Linux

Section I. Getting started with Volume Replicator
Section II. Setting up and administering VVR
Section III. Getting started with File Replicator
1. Introducing File Replicator
  1. About File Replicator
    1. Features of VFR
    2. File Replicator limitations
  2. How File Replicator works
    1. About error recovery after a site disaster or network disruption using VFR
    2. About File Replicator log files
2. Administering File Replicator
Section IV. Analyzing your environment with Volume Replicator Advisor
Section V. VVR reference

Recovery from RLINK connect problems

This section describes the errors that may be encountered when connecting RLINKs. To be able to troubleshoot RLINK connect problems, it is important to understand the RLINK connection process.

Connecting the Primary and Secondary RLINKs is a two-step operation. The first step, which attaches the RLINK, is performed by issuing the vradmin startrep command. The second step, which connects the RLINKs, is performed by the kernels on the Primary and Secondary hosts.

When the vradmin startrep command is issued, VVR performs a number of checks to ensure that the operation is likely to succeed, and if it does, the command changes the state of the RLINKs from DETACHED/STALE to ENABLED/ACTIVE. The command then returns success.

If the command is successful, the kernel on the Primary is notified that the RLINK is enabled and it begins to send messages to the Secondary requesting it to connect. Under normal circumstances, the Secondary receives this message and connects. The state of the RLINKs then changes from ENABLED/ACTIVE to CONNECT/ACTIVE.

If the RLINK does not change to the CONNECT/ACTIVE state within a short time, there is a problem preventing the connection. This section describes a number of possible causes. An error message indicating the problem may be displayed on the console.

If the following error displays on the console:
```
VxVM VVR vxrlink INFO V-5-1-5298 Unable to establish connection
 with remote host <remote_host>, retrying
```
Make sure that the vradmind daemon is running on the Primary and the Secondary hosts; otherwise, start the vradmind daemon by issuing the following command:
For systemd environments with supported Linux distributions:
```
# systemctl start vras-vradmind.sh
```
For other supported Linux distributions:
```
# /etc/init.d/vras-vradmind.sh start
```
For an RLINK in a shared disk group, make sure that the virtual IP address of the RLINK is enabled on the logowner.
If there is no self-explanatory error message, issue the following command on both the Primary and Secondary hosts:
```
# vxprint -g diskgroup -l rlink_name
```
In the output, check the following:
The remote_host of each host is the same as local_host of the other host.
The remote_dg of each host is the same as the disk group of the RVG on the other host.
The remote_dg_dgid of each host is the same as the dgid (disk group ID) of the RVG on the other host as displayed in the output of the vxprint -l diskgroup command.
The remote_rlink of each host is the same as the name of the corresponding RLINK on the other host.
The remote_rlink_rid of each host is the same as the rid of the corresponding RLINK on the other host.
Make sure that the network is working as expected. Network problems might affect VVR, such as prevention of RLINKs from connecting or low performance. Possible problems could be high latency, low bandwidth, high collision counts, and excessive dropped packets.
For an RLINK in a private disk group, issue the following command on each host.
For an RLINK in a shared disk group, use vxprint -Vl | grep logowner to find the logowner node, then issue the following command on the logowner on the Primary and Secondary.
```
# ping remote_host
```
Note:
This command is only valid when ICMP ping is allowed between the VVR Primary and the VVR Secondary.
After 10 iterations, type Ctrl-C. There should be no packet loss or very little packet loss. To ensure that the network can transmit large packets, issue the following command on each host for an RLINK in a private disk group.
For an RLINK in a shared disk group, issue the following command on the logowner on the Primary and Secondary:
```
# ping -s 8192 remote_host
```
The packet loss should be about the same as for the earlier ping command.
Issue the vxiod command on each host to ensure that there are active I/O daemons. If the output is 0 volume I/O daemons running, activate I/O daemons by issuing the following command:
```
# vxiod set 10
```
VVR uses well-known ports to establish communications with other hosts.
Issue the following command to display the port number:
```
# vxprint -g diskgroup -l rlink_name
```
Issue the following command to ensure that the heartbeat port number in the output matches the port displayed by vxprint command:
```
# vrport
```
Confirm that the heartbeat port has been opened by issuing the following command:
```
# netstat -an | grep port-number
```
where port-number is the port number being used by the heartbeat server as displayed by the vrport command.
The output looks similar to this:
```
    udp     0    0     0,0,0,0:port-number
```
Check for VVR ports on the Primary and Secondary sites.
Run the vrport utility and verify that ports are same at both ends.
Check whether the required VVR ports are open. Check for UDP 4145, TCP 4145, TCP 8199, and the anonymous port. Enter the following commands:
```
# netstat -an --udp | grep 4145
udp        0      0 :::4145                     :::*
# netstat -an --tcp | grep 4145
tcp        0      0 :::4145                     :::*                LISTEN
# netstat -an --tcp | grep 8199
tcp        0      0 :::8199                     :::*                LISTEN
```
Perform a telnet test to check for open ports. For example, to determine if port 4145 is open, enter the following:
```
# telnet <remote> 4145
```

Use the netstat command to check if vradmind daemons can connect between the Primary site and the Secondary site:

# netstat -an --tcp | grep 8199 | grep ESTABLISHED
tcp        0      0 10.209.85.18:56872      10.209.85.19:8199       ESTABLISHED
tcp        0      0 10.209.87.175:8199      10.209.85.23:42860      ESTABLISHED
tcp        0      0 10.209.87.175:8199      10.209.87.176:9335      ESTABLISHED