Description

The following VVR settings are advised as Best Practice from InfoScale 7.4.1 onwards.

Before changing any of the VVR tunable values, pause replication links on both VVR Primary and Secondary

Note:  From InfoScale 7.4.1 onwards, we don't recommend tuning nmcom_max_connections to 16, 24 or 32 as previously advised.
 

1.] Pause rlink on both primary and secondary servers

# vxrlink -g DG pause rlink-name


2.] Ensure Secondary logging and Bulk transfer are set to 1 across all nodes

# vxtune hidden | egrep "vol_rv_sec_logging_enabled|vol_rv_do_secondary_logging|vol_rv_bulk_transfer"

# vxtune vol_rv_do_secondary_logging 1

# vxtune vol_rv_sec_logging_enabled 1

# vxtune vol_rv_bulk_transfer 1

# vxtune hidden | egrep "vol_rv_sec_logging_enabled|vol_rv_do_secondary_logging|vol_rv_bulk_transfer"

vol_rv_bulk_transfer                                       1                            1    N        N
vol_rv_do_secondary_logging                                1                            1    N        N
vol_rv_sec_logging_enabled                                 1                            1    N        N

3.] Ensure the VVR protocol is set to TCP for all RVGs.

# vradmin -g DG set rvg_name protocol=TCP 

# vxprint -Pl |grep -i protocol

protocol: TCP/IP


4.] Set the nmcom_max_connections value to 1.

# vxtune nmcom_max_connections

# vxtune nmcom_max_connections 1

# vxtune nmcom_max_connections

Tunable                                        Current Value                Default Value Reboot Clusterwide
-------------------------------                -------------                ------------- ------ -----------
nmcom_max_connections                                      1                            1    N        N

5.] Set nports to 16.

# vradmin -g DG set rvg_name nports=16 

Use vxprint -Pl to verify the nport value.

# vxprint -Pl |grep -i nports
 nports=16
 

6.] Verify the current and maximum Ring parameter values are set for the RX  & TX values shown  below

In this instance, the maximum value is 4096 for RX  and TX.

The  rx/tx ring parameters can be configured using the ethtool command.

In this instance, the eth5 device is shown for illustration purposes:

# ethtool -g eth5
Ring parameters for eth5:
Pre-set maximums:
RX:             4096
RX Mini:        2048
RX Jumbo:       4096
TX:             4096
Current hardware settings:
RX:             1024
RX Mini:        128
RX Jumbo:       512
TX:             512
 

To change the tx value to the maximum support value for eth5, type:

# ethtool -G eth5 tx 4096

To change the rx value to the maximum support value for eth5, type:

#  ethtool -G eth5 rx 4096

Where bonded devices are configured, repeat the steps for the alternate devices, in this instance eth3:

To change the tx value to the maximum support value for eth5, type:

# ethtool -G eth3 tx 4096

To change the rx value to the maximum support value for eth5, type:

#  ethtool -G eth3 rx 4096

7.] Resume rlink on both primary and secondary servers

# vxrlink -g DG resume rlink-name