Uploaded image for project: 'XenServer Org'
  1. XenServer Org
  2. XSO-449

MTU issue on XAPI interfaces: MTU cannot be changed

    XMLWordPrintable

    Details

    • Type: Bug
    • Status: Done (View Workflow)
    • Priority: Critical
    • Resolution: Done
    • Affects Version/s: 6.5 SP1, 7.0, 7.1, 7.2
    • Fix Version/s: 7.3
    • Component/s: Networking
    • Labels:
    • Environment:

      Both vswitch and bridge modes are affected. Bridge mode has workaround via manual MTU tuning on vif's and bond vlans, vswitch mode has no means to fix it.

      Description

      MTU on secondary management (xapi1 in our case) used for SAN connection has dropped to 1500 after update/reboot on all hosts, and cannot be changed anymore. This VLAN is also used by some VMs.

      1. ifconfig xapi1
        xapi1 Link encap:Ethernet HWaddr A4:BA:DB:09:B4:16
        inet addr:192.168.0.86 Bcast:192.168.0.255 Mask:255.255.255.0
        UP BROADCAST RUNNING MTU:1500 Metric:1

      ifconfig xapi1 mtu 9000 does nothing - 1500 still shown. Related VIFs/PIFs and XenCenter show MTU 9000 on the VLAN. All VIF ports inside xapi1 listed via ovs-vsctl show MTU of 9000.

      Tried to create VLAN with another management IP/netmask, not used by any VM. Got the same issue.

      This is major, because it affects SAN access performance rather badly.

      Probably openvswitch update related. We'll try switching to bridge mode and see if the problem still exist.

        Attachments

          Issue Links

            Activity

              People

              Assignee:
              rosslagerwall Ross Lagerwall
              Reporter:
              Alex/AT Alexey Asemov
              Votes:
              3 Vote for this issue
              Watchers:
              13 Start watching this issue

                Dates

                Created:
                Updated:
                Resolved: