By default, ESXi installer creates core dump partition of 2.5GB on the boot device for vSphere 5.5 & above. The coredump partition size usage depends upon the ESXi DRAM and vSAN usage.
The process of coredump partition resizing is different in vSAN 6.5/vSAN 6.6 nodes. Starting from vSAN 6.7, no manual resizing is required.
When we mention vSAN, hypervisor can be installed on USB/SD media or SATADOM/Disk. In both of the installation media methods ESXi installer has different ways of creating partitions.
Unlike disk-based installations, ESXi installer does not create scratch partition & vmfs partition in USB/SD media. Scratch contents are stored in Ramdisk in USB/SD based installation.
vSAN 6.7 introduces enhanced core dump partition support where in it supports automatically extending the vmkcore partition when free space is available. In 6.7, no manual resizing is required like vSan 6.5/6.6.
The following vSAN operations require increased coredump partition size:
- Enabling vSAN
- Adding diskgroups
- Cache tier SSD large sizes
- Host DRAM size
Now, we will discuss what are the scenarios where coredump partition size cannot be increased
- When using disk-based installation media, no space is left over in the device because in disk-based media free space is formatted with vmfs.
- When SD/USB has insufficient space.
We can use below options as an alternative:
» Use vmfs volume to configure ESXi core dumps to file instead of partition
» ESXi dump collector service can be configured in vCenter Server
» Separate partition can be configured and existing coredump partition settings can be modified
» Log locations for more information about coredump partition expansion failed and recommended sizes
I hope this has been informative for you. Thank you for reading!!