Supported Kdump Targets

This document try to list all supported kdump targets, and those supported

or unknown/tech-preview targets, this can help users to decide whether a dump

solution is available.

Dump Target support status

==========================

This section tries to come up with some kind of guidelines in terms of

what dump targets are supported/not supported. Whatever is listed here

is not binding in any manner. It is just sharing of current understanding

and if something is not right, this section needs to be edited.

Following are 3 lists. First one contains supported targets. These are

generic configurations which should work and some configuration most

likely has worked in testing. Second list is known unsupported targets.

These targets we know either don't work or we don't support. And third

list is unknown/tech-preview. We either don't yet know the status of kdump

on these targets or these are under tech-preview.

Note, these lists are not set in stone and can be changed at any point of

time. Also these lists might not be complete. We will add/remove items to

it as we get more testing information. Also, there are many corner cases

which can't possibly be listed. For example in general we might be

supporting software iscsi but there might be some configurations of it

which don't work.

So if any target is listed in supported section, it does not mean it works

in all possible configurations. It just means that in common configurations

it should work but there can be issues with particular configurations which

are not supported. As we come to know of particular issues, we will keep on

updating lists accordingly.

Supported Dump targets

----------------------

storage:

        LVM volume (no thinp)

        FC disks (qla2xxx, lpfc, bnx2fc, bfa)

        software initiator based iSCSI

        software RAID (mdraid)

        hardware RAID (cciss, hpsa, megaraid_sas, mpt2sas, aacraid)

        SCSI/SATA disks

        iSCSI HBA (all offload)

        hardware FCoE (qla2xxx, lpfc, bfa)

        software FCoE (bnx2fc, fcoe/ixgbe) (Extra configuration required,

            please read "Note on FCoE" section below)

network:

        Hardware using kernel modules: (tg3, igb, ixgbe, sfc, e1000e, bna,

              cnic, netxen_nic, qlge, bnx2x, bnx, qlcnic, be2net, enic,

              virtio-net, ixgbevf, igbvf)

        protocol: ipv4

        bonding

        vlan

        bridge

        team

        vlan tagged bonding

        bridge over bond/team/vlan

hypervisor:

        kvm

        xen (Supported in select configurations only)

filesystem:

        ext[234]

        xfs

        nfs

firmware:

        BIOS

        UEFI

hypervisor:

        VMWare ESXi 4.1 and 5.1

        Hyper-V 2012 R2 (RHEL Gen1 UP Guest only)

Unsupported Dump targets

------------------------

storage:

        BIOS RAID

        Thin provisioning volume

        Software iSCSI with iBFT (bnx2i, cxgb3i, cxgb4i)

        Software iSCSI with hybrid (be2iscsi)

        FCoE

        legacy IDE

        glusterfs

        gfs2/clvm/halvm

network:

        hardware using kernel modules: (sfc SRIOV, cxgb4vf, pch_gbe)

        protocol: ipv6

        wireless

        Infiniband (IB)

        vlan over bridge/team

filesystem:

        btrfs

Unknown/tech-preview

--------------------

storage:

        PCI Express based SSDs

hypervisor:

        Hyper-V 2008

        Hyper-V 2012

Note on FCoE

=====================

If you are trying to dump to a software FCoE target, you may encounter OOM

issue, because some software FCoE requires more memory to work. In such case,

you may need to increase the kdump reserved memory size in "crashkernel="

kernel parameter.

By default, RHEL systems have "crashkernel=auto" in kernel boot arguments.

The auto reserved memory size is designed to balance the coverage of use cases

and an acceptable memory overhead, so not every use case could fit in, software

FCoE is one of the case.

For hardware FCoE, kdump should work naturally as firmware will do the

initialization job. The capture kernel and kdump tools will run just fine.

Useful Links

============

[1] RHEL6: Enabling kdump for full-virt (HVM) Xen DomU

    (https://access.redhat.com/knowledge/solutions/92943)