What targets are supported for use with kdump?

Solution Verified - Updated

Environment

  • Red Hat Enterprise Linux 9
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 5

Issue

  • What are valid Red Hat supported targets that kdump can use to dump a vmcore?
  • What kdump targets are currently unsupported?

Resolution

Kdump stands for kernel dump. It's a method used to save a system's vmcore when a system crash occurs. Red Hat Support Engineers can then analyse the vmcore to help determine the reason for the crash. For a guide on how to configure and use the kdump mechanism, see How do I configure kexec/kdump on Red Hat Enterprise Linux?

The supported dump targets are:

  • ext2, ext3, ext4, minix, btrfs and xfs filesystems on direct attached single drives, hardware RAID logical drives, LVM devices, and mdraid arrays.
    • LVM limitations: thin provisioned logical volumes are not supported at kdump targets in any current kexec-tools version on any RHEL kernel.
    • RHEL 7+ limitations: none for the above filesystems
    • RHEL 6 limitations: xfs and btrfs are only supported with kexec-tools version 2.0.0-123 or higher
    • RHEL 5 limitations: btrfs is not supported and xfs is only supported with kexec-tools version 1.102pre-154 or higher.
  • locally attached raw disks and partitions
  • NFS filesystems mounted over IPv4
  • remote SSH connections over IPv4
    • RHEL 7+: remote SSH connections over IPv6 in RHEL 7 or later with kexec-tools version 2.0.7-38 and higher (circa 11/2015)
  • multipath based storage
    • RHEL 7+: iSCSI software initiator multipath devices supported
    • RHEL6 : prior to kexec-tools version 2.0.00-245 or higher, multipath devices over iSCSI software initiator are not supported
    • RHEL5 : iSCSI software initiator multipath devices not supported
  • iSCSI devices over software initiator
  • SAN devices connected through full h/w offload of FCoE HBAs
    (unlike partial h/w offload FCoE adapters, this type of FCoE HBAs would be listed directly in lspci output)
  • virtio filesystem (virtiofs):
    • RHEL 9.2+: The kexec-tools version 2.0.25-13.el9_2 or higher supports the virtio filesystem (virtiofs).
    • RHEL 8 limitation: Sharing files between the host and its VMs using the virtiofs filesystem is unsupported.

Dump targets which are currently unsupported are:

  • eCryptfs (due to reliance on user interaction to unlock the device)
  • iSCSI over hardware based initiators
  • Partial h/w offload FCoE (Fibre Channel over Ethernet) initiators
    (Note: Full h/w offload FCoE initiators are still supported as mentioned above)
  • CIFS/SMB
  • NFS rootfs
  • IPv6 based network protocols (RHEL 5, 6 only)
  • Wireless network interfaces
  • Powerpath devices
  • swap devices (if swap is enabled before the core is saved during boot it could cause corruption of the core)
  • dmraid, BIOS RAID
  • Veritas filesystems
  • Any clustered filesystem including GFS, GFS2, and OCFS2
  • LUKS filesystems
  • OracleASM dump targets or systems with OracleASM managed devices providing /boot or /
  • Thin provisioning volume
  • AWS storage devices

note: "unsupported" means these might work in some circumstances but not in others and are not supported by Red Hat as a valid kdump target. Being unsupported means support is not available from Red Hat if attempting to use any of these as a kdump target and it does not work or fails to consistently work.

  • Check below doc for supported dump target in specific kexec version.
    • RHEL 9: $ less /usr/share/doc/kexec-tools/supported-kdump-targets.txt
    • RHEL 8: $ less /usr/share/doc/kexec-tools/supported-kdump-targets.txt
    • RHEL 7: $ less /usr/share/doc/kexec-tools-2*/supported-kdump-targets.txt
    • RHEL 6: $ less /usr/share/doc/kexec-tools-2*/kexec-kdump-howto.txt
    • RHEL 5: $ less /usr/share/doc/kexec-tools-1*/kexec-kdump-howto.txt
SBR
Product(s)
Components
Category
Tags

This solution is part of Red Hat’s fast-track publication program, providing a huge library of solutions that Red Hat engineers have created while supporting our customers. To give you the knowledge you need the instant it becomes available, these articles may be presented in a raw and unedited form.