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VSICM51 - Slide 14-10 - Booting from SAN


Slide notes show an unordered list of requirements for configuring a diagnostic partition on a shared SAN LUN for hosts booting from SAN.

You must configure a diagnostic partition on a shared SAN LUN. The diagnostic partition is accessed by multiple hosts and can store fault information for more than one host.
  • If more than one ESXi host uses the same LUN as the diagnostic partition, that LUN must be zoned so that all the servers can access it.
  • Each server requires 100MB of space, so the size of the LUN determines how many servers can share it. Each ESXi host is mapped to a diagnostic slot. VMware recommends at least 16 slots (1,600MB) of disk space if servers share a diagnostic partition.
  • If the device has only one diagnostic slot, all ESXi hosts sharing that device map to the same slot. This setup can easily create problems. If two ESXi hosts perform a core dump at the same time, the core dumps are overwritten on the diagnostic partition.
  • If you use iSCSI Boot Firmware Table (iBFT) to boot an ESXi host from a SAN LUN, you cannot set up a diagnostic partition on the SAN LUN. Instead, you use the VMware vSphere® Management Assistant (vMA) to collect diagnostic information from your host and store it for analysis.
Room for improvement:

In vSphere 5.x, administrators can also leverage the VMware vSphere Network Dump Collector service. The VMware Knowledgebase article number 1032051 offers an overview of the Dump Collector functionality.

The VMware vSphere Network Dump Collector service enables a host to transmit diagnostic information via the network to a remote netdump service, which stores it on disk. Network-based coredump collection can be configured in addition to or instead of disk-based coredump collection. This may be useful in stateless environments with no local disk usable for a diagnostic partition.

The Dump Collector is available in two forms:
   -  vSphere ESXi Dump Collector service installed on Windows, possibly in the same location as vCenter Server.
   -  vSphere ESXi Dump Collector service pre-packaged with the vCenter Server Virtual Appliance.

When installed on Windows, the vSphere ESXi Dump Collector service can integrate with vCenter Server. The Dump Collector server's listening IP address and Port number will be listed in the Dump Collector vCenter Server plugin. This is not available in a standalone installation of vSphere Dump Collector on Windows or in the vCenter Server Virtual Appliance.

VMware Knowledge Base articles.

Last modified onThursday, 12 December 2013 18:07
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