Error Message

Aug  8 22:01:05 server101 llt: LLT lltconfig ERROR V-14-2-15834 MTU size for link (ens33) is not optimal, please set it to 1500 or 9000 for optimal performance
Aug  8 22:01:05 server101 llt: LLT lltconfig ERROR V-14-2-15834 MTU size for link (ens34) is not optimal, please set it to 1500 or 9000 for optimal performance
Aug  8 22:01:05 server101 llt: LLT lltconfig ERROR V-14-2-15850 Not enough valid links to configure UDP multiport
Aug  8 22:01:05 server101 llt: LLT lltconfig ERROR V-14-2-15800 UDP multiport:Failed to get link info
Aug  8 22:01:05 server101 llt: LLT lltconfig ERROR V-14-2-15832 LLT could not configure UDP multiport
Aug  8 22:01:05 server101 kernel: LLT INFO V-14-1-10550 llt_setparam: Successfully set the LLT tunable  *Strict Source Check(llt_strictsrc)* from 0 to 1 on user request.

Observations

- ifconfig output showing the MTU as 1500
- lltstat -l output showing the mtu as 1058

      
# lltstat -l 
LLT link information:
link 0  eth2 on udp hipri
        mtu 1058, sap 0xc350, broadcast 10.255.255.255, addrlen 4
        txpkts 351479  txbytes 344083589
        rxpkts 149009  rxbytes 108324699
        latehb 0  badcksum 0  errors 0
link 1  eth3 on udp hipri
        mtu 1058, sap 0xc351, broadcast 10.255.255.255, addrlen 4
        txpkts 351673  txbytes 344186433
        rxpkts 149106  rxbytes 108454199
        latehb 0  badcksum 0  errors 0

- llttab MTU field is kept with 1100

# cat /etc/llttab
set-node server101
set-cluster 12310
link ens33 udp - udp 50000 1100 192.168.20.101 -
link ens34 udp - udp 50001 1100 192.168.30.101 -
set-addr 1 ens33 192.168.20.102
set-addr 1 ens34 192.168.30.102
set-bcasthb 0
set-arp 0
 

UDP multiport requires MTU 1500 and above. Here llttab configured with 1100 MTU. 

Modified the llttab with 1500 MTU and restarted all the VCS modules including the LLT.