Forum Discussion

joagmv's avatar
joagmv
Level 4
12 years ago
Solved

Online config LLT interface

Recently I realized that a llt interface in a cluster is not working because the nodes are in different vlans (the interface uses broadcast conf):

 

Node 0:
 
NODE0:~ # cat /etc/llttab
set-node NODE0
set-cluster 1047
set-timer peerinact:3200
link eth2 eth-00:10:18:0b:7e:12 - ether - -
link eth3 eth-00:10:18:0b:7e:13 - ether - -
link-lowpri eth0 eth-00:14:5e:7b:08:1a - ether - -
 
NODE0:~ # ifconfig eth0
eth0      Link encap:Ethernet  HWaddr 00:14:5E:7B:08:1A  
          inet addr:10.92.5.134  Bcast:10.92.5.255  Mask:255.255.254.0
 
 
Node 1:
 
NODE1:~ # cat /etc/llttab
set-node NODE1
set-cluster 1047
set-timer peerinact:3200
link eth2 eth-00:0e:0c:ba:3e:ae - ether - -
link eth3 eth-00:0e:0c:ba:41:96  - ether - -
link-lowpri eth0 eth-00:14:5e:7a:aa:3c - ether - -
 
NODE1:~ # ifconfig eth0
eth0      Link encap:Ethernet  HWaddr 00:14:5E:7A:AA:3C  
          inet addr:10.93.146.123  Bcast:10.93.147.255  Mask:255.255.254.0
 
 
I think I should configure eth0 as an UDP interface, shouldn't I?? I tried somethink like that and It seemed to work:
 
Node 0:
 
//Specifying the other node IP as the broadcast address
lltconfig -t eth0 -d eth0 -b udp -I 10.92.5.134 -B 10.93.146.124
 
Node 1:
 
//Specifying the other node IP as the broadcast address
lltconfig -t eth0 -d eth0 -b udp -I 10.93.146.123 -B 10.92.5.134
 
Is this correct?? What should I define in the llttab file??
 
Regards,
joagmv
business continuity
Cluster Server
Configuring
Linux
Troubleshooting
  • mikebounds's avatar
    mikebounds
    Level 6
    12 years ago

    There is a sample llttab file for LLT over UDP at https://www-secure.symantec.com/connect/forums/if-llt-could-be-configured-over-udp-nat#comment-7542471.

     

    Note also, you can't mix LLT over UDP and LLT over Ethernet - see https://www-secure.symantec.com/connect/forums/how-configure-llt-over-udp-when-you-have-more-1-node-each-site#comment-7189341

    So your config will look something like:

     

    set-node NODE0
    set-cluster 1047
    link hb-eth2-nat /dev/udp - udp 50100 - IP-on-eth2-on-node0 -
    link hb-eth3-nat /dev/udp - udp 50101 - IP-on-eth3-on-node0 -
    link-lowpri hb-eth0 /dev/udp - udp 50102 - 10.92.5.134 -
     
    set-addr 1  hb-eth2 IP-on-eth2-on-node1
    set-addr 1  hb-eth2 IP-on-eth3-on-node1
    set-addr 1  hb-eth0 10.93.146.123
     
    #disable LLT broadcasts
    set-bcasthb 0
    set-arp 0

    I have just chosen 3 UDP ports at random - 50100, 50101, 50102.

    Mike

  • joagmv's avatar
    joagmv
    Level 4
    12 years ago

    Very helpful Mike.

    So, are the commands I executed correct?? I mean, does the command "lltconfig -l -t eth0 -d eth0 -b udp -I 10.92.5.134 -B 10.93.146.124" translate to

     

    link-lowpri hb-eth0 /dev/udp - udp 50102 - 10.92.5.134 -
    set-addr 1  hb-eth0 10.93.146.123
     
    ???

    The main doubt I have is about the -B param...

  • mikebounds's avatar
    mikebounds
    Level 6
    12 years ago

    The VCS install guide says:

     

    Use LLT over UDP in the following situations:
     
    ■ LLT must be used over WANs
    ■ When hardware, such as blade servers, do not support LLT over Ethernet
     
    LLT over UDP is slower than LLT over Ethernet. Use LLT over UDP only when the
    hardware configuration makes it necessary.
     
    And also says:
    The set-addr command in the /etc/llttab file is required when the broadcast
    feature of LLT is disabled, such as when LLT must cross IP routers.
     
    So my understanding is that if you have hardware, such as blade servers, that does not support LLT over Ethernet, then you use Broadcast feature, otherwise, for WANs when LLT must cross IP routers you disable broadcast and use specific IPs.
     
    So the "-B" is for broadcast address, but you have not set a broadcast address, so I am surprised your command resulting in a working config.    The broadcast address is the last arg in the llttab, so an example of lines in the llttab when using broadcast feature is:
     
    link link1 /dev/udp - udp 50000 - 192.168.30.1 192.168.30.255
    link link2 /dev/udp - udp 50001 - 192.168.31.1 192.168.31.255
     
    So if you actually put in your broadcast so ran:
    lltconfig -l -t eth0 -d eth0 -b udp -I 10.92.5.134 -B 10.92.5.255
     
    then I suspect it won't work as broacast won't cross routers and by using an IP in place of broadcast address, probably means your config is not supported.
     
    Mike
     
     

     

  • joagmv's avatar
    joagmv
    Level 4
    12 years ago

    If i define the -B as the actual broadcast address, It doest work:

     

    NODE0:~ # ifconfig eth0
    eth0      Link encap:Ethernet  HWaddr 00:14:5E:7B:08:1A  
              inet addr:10.92.5.134  Bcast:10.92.5.255  Mask:255.255.254.0
     
    NODE1:~ # ifconfig eth0
    eth0      Link encap:Ethernet  HWaddr 00:14:5E:7A:AA:3C  
              inet addr:10.93.146.123  Bcast:10.93.147.255  Mask:255.255.254.0
     
    NODE0:/etc # lltconfig -t eth0 -d eth0 -b udp -I 10.92.5.134 -B 10.92.5.255
    NODE1:/etc # lltconfig -t eth0 -d eth0 -b udp -I 10.93.146.123 -B 10.93.147.255
     
    NODE0:/etc # lltstat -nvv | head
    LLT node information:
        Node                 State    Link  Status  Address
       * 0 NODE0         OPEN    
                                      eth2   UP      00:10:18:0B:7E:12
                                      eth3   UP      00:10:18:0B:7E:13
                                      eth0   UP      10.92.5.134
         1 NODE1         OPEN    
                                      eth2   UP      00:0E:0C:BA:3E:AE
                                      eth3   UP      00:0E:0C:BA:41:96
                                      eth0   DOWN    
     
    NODE1:/etc # lltstat -nvv | head
    LLT node information:
        Node                 State    Link  Status  Address
         0 NODE0         OPEN    
                                      eth2   UP      00:10:18:0B:7E:12
                                      eth3   UP      00:10:18:0B:7E:13
                                      eth0   DOWN    
       * 1 NODE1         OPEN    
                                      eth2   UP      00:0E:0C:BA:3E:AE
                                      eth3   UP      00:0E:0C:BA:41:96
                                      eth0   UP      10.93.146.123
     
    BUT, if I define the broadcast as the other IP, it works:
     
    NODE0:/etc # lltconfig -u eth0
    NODE0:/etc # lltconfig -t eth0 -d eth0 -b udp -I 10.92.5.134 -B 10.93.146.123
     
    NODE1:~ # lltconfig -u eth0
    NODE1:~ # lltconfig -l -t eth0 -d eth0 -b udp -I 10.93.146.123 -B 10.92.5.134
     
    NODE0:~ # lltstat -nvv | head
    LLT node information:
        Node                 State    Link  Status  Address
       * 0 NODE0         OPEN    
                                      eth2   UP      00:10:18:0B:7E:12
                                      eth3   UP      00:10:18:0B:7E:13
                                      eth0   UP      10.92.5.134
         1 NODE1         OPEN    
                                      eth2   UP      00:0E:0C:BA:3E:AE
                                      eth3   UP      00:0E:0C:BA:41:96
                                      eth0   UP      10.93.146.123
     
    So... my doubt is about taking off the low-priority interface (we do not eant to pass the others LLT interfaces to UDP or just leaving the config that (mixing llt and udp with the broadcast trick...
     
    Regards,
    Joaquín