IBM Storwize v7000 - MTU setting

MTU Settings

On the IBM Storwize v7000 I was told the default settings of the MTU was 9000 Jumbo Frames, while dealing with a problem of one of the VMware hosts dropping one of the iSCSI paths, Support suggested I check the MTU setting on the v7000.

After spending a fair bit of time trying to find out how to check the MTU setting and being previously told by IBM you can't change it I found the following.

Command to view settings

lsportip:

Use the lsportip command to list the Internet Small Computer Systems Interface (iSCSI) Internet Protocol (IP) addresses assigned for each port on each node in the clustered system.

Example command: svcinfo lsportip this will display the following.

I used the -delim to seperate it with :

full command:  svcinfo lsportip -delim :

id:node_id:node_name:IP_address:mask:gateway:IP_address_6:prefix_6:gateway_6:MAC:duplex:state:speed:failover:link_state

1:1:node1:::::::e4:1f:13:75:81:xx:Full:unconfigured:1Gb/s:no:active

1:1:node1:::::::e4:1f:13:75:81:xx:Full:unconfigured:1Gb/s:yes:active

2:1:node1:::::::e4:1f:13:75:81:xx:Full:unconfigured:1Gb/s:no:active

2:1:node1:::::::e4:1f:13:75:81:xx:Full:unconfigured:1Gb/s:yes:active

3:1:node1:10.10.11.1:255.255.255.0:10.10.11.254::::00:00:c9:d2:ed:xx:Full:configured:10Gb/s:no:active

3:1:node1:::::::00:00:c9:d2:ed:xx:Full:configured:10Gb/s:yes:active

4:1:node1:10.10.12.1:255.255.255.0:10.10.12.254::::00:00:c9:d2:ed:xx:Full:configured:10Gb/s:no:active

4:1:node1:::::::00:00:c9:d2:ed:xx:Full:configured:10Gb/s:yes:active

1:2:node2:::::::e4:1f:13:75:b0:xx:Full:unconfigured:1Gb/s:no:active

1:2:node2:::::::e4:1f:13:75:b0:xx:Full:unconfigured:1Gb/s:yes:active

2:2:node2:::::::e4:1f:13:75:b0:xx:Full:unconfigured:1Gb/s:no:active

2:2:node2:::::::e4:1f:13:75:b0:xx:Full:unconfigured:1Gb/s:yes:active

3:2:node2:10.10.11.2:255.255.255.0:10.10.11.254::::00:00:c9:d9:4a:xx:Full:configured:10Gb/s:no:active

3:2:node2:::::::00:00:c9:d9:4a:xx:Full:configured:10Gb/s:yes:active

4:2:node2:10..10.12..2:255.255.255.0:10.10.12.254::::00:00:c9:d9:4a:xx:Full:configured:10Gb/s:no:active

4:2:node2:::::::00:00:c9:d9:4a:xx:Full:configured:10Gb/s:yes:active

to see the NIC setting select the appropriate id this can be done by doing the following command:

full command: svcinfo lsportip 1 where 1 is the ethernet port id this will display something similar to the following.

id 1

node_id 2

node_name node2

IP_address

mask

gateway

IP_address_6

prefix_6

gateway_6

MAC e4:1f:13:75:xx:xx

duplex Full

state unconfigured

speed 1Gb/s

failover no

mtu 1500

link_state active

You can see that the MTU is 1500 on the 1Gbs interfaces it is also 1500 on the 10Gbs interfaces 

id 3

node_id 2

node_name node2

IP_address 10.10.11.2

mask 255.255.255.0

gateway 10.10.11.254

IP_address_6

prefix_6

gateway_6

MAC 00:00:c9:d9:xx:xx

duplex Full

state configured

speed 10Gb/s

failover no

mtu 1500

link_state active

To make changes to these setting use svctask cfgportip command.

You can find more details in the IBM v7000 InfoCenter and in the IBM Storwize v7000 Command-Line Interface Users Guide 6.4.1, If you google these you will find them on line.