Tools overview

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Different tools can be used for obtaining dumps of Linux® instances running on IBM Z® or IBM® LinuxONE (LinuxONE) servers.
Note: As of IBM z13®, simultaneous multithreading is available for Linux in LPAR mode. You must use dump tools that support multithreading on such LPARs. See Dump tool version dependencies.

You can use the dump analysis tool crash to analyze a dump. Depending on your support contract, you might also want to send a dump to IBM Support to be analyzed.

Table 1 and Table 2 summarize the available dump tools:

Table 1. Dump tools summary
Dump aspect kdump CCW DASD Multi-volume DASD List-directed DASD SCSI
Environment (see note 1) KVM, z/VM®, and LPAR z/VM and LPAR z/VM and LPAR LPAR z/VM and LPAR
System size (see note 2) Large Small Large Large Large
Speed Fast Fast Fast Fast Fast
Medium Any available medium ECKD™ or FBA DASD (see note 3) ECKD DASD ECKD DASD SCSI partition
Compression possible While writing While writing No No No
Dump filtering possible While writing When copying When copying When copying When copying
Disruptive (see note 4) Yes Yes Yes Yes Yes
Stand-alone No Yes Yes Yes Yes
Table 2. Dump tools summary, cont.
Dump aspect NVMe Tape virsh dump VMDUMP Live-system dump with zgetdump
Environment (see note 1) LPAR z/VM and LPAR KVM only z/VM only z/VM and LPAR
System size (see note 2) Large Large Large Small Large
Speed Fast Slow Fast Slow Fast
Medium NVMe disk partition Tape cartridges Any available medium z/VM reader Any available medium
Compression possible No Yes (see note 2) No No No
Dump filtering possible While writing and when copying When copying When copying When copying No
Disruptive (see note 4) Yes Yes Optional No No
Stand-alone Yes Yes No No No
Note:
  1. Dump tools that are available for an LPAR environment are also available for supported storage types in DPM partitions. For information about IPL-initiated dump types supported in DPM partitions, see the DPM documentation.
  2. For dump system sizes, see also Maximum dump size by tool.
  3. SCSI disks can be emulated as FBA DASDs. This dump method can, therefore, be used for SCSI-only z/VM installations.
  4. In this context, disruptive means that the dump process kills a running operating system.