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vSphere 4-5+ - ESXi 4-5+ - Installing ESXi on a flash drive (SD or USB)

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vSphere 4-5+ - ESXi 4-5+ - Installing ESXi on a flash drive (SD or USB)

Postby lmmtux » Thu Apr 03, 2014 9:20 am

ESXi can be installed on a flash drive, USB or SD type, allowing regular storage to be used for datastores. Here are some tips and considerations for doing so.

ESXi limitations on flash media

Installing ESXi on flash media has a few limitations, however they are very minor and the convenience of using flash media greatly outweighs them.

  • Slightly slower boot time than standard disks. Do your homework on the flash media for your server, it really can make a difference in speed. Check compatibility and speed ratings and try to stick with name brand media.
  • Long term reliability. Flash media has a finite number of theoretical writes to the media. The greater the flash media size, the better the "wear leveling" features and greater surface area that writes can be spread, extending the life of the flash itself.
  • ESXi logs stored on a datastore or syslog. By default, ESXi will not enable the "scratch" partition on the flash media if it's smaller than 8 GB in size, due to the "wear leveling" feature mentioned above. Read below for the recommended setup to get around this.

Recommended setup

  • Install ESXi as normal. When prompted for which disk to install to, select the flash media. Note: Some systems will already have the flash media partitioned (for example for Cisco UCS servers, 4 partitions are set up and one of the partitions are meant for the hypervisor OS, usually called "HV").
    installflash.jpg (21.61 KiB) Viewed 3038 times
  • After ESXi is up and running, logs should be enabled on a datastore. Normally this should be a local datastore so that the host can always write to it even if there's a storage connectivity issue. To set logs to write to a datastore, do the following:
    • Open the vSphere client and navigate to the ESXi host.
    • Click on the Configuration tab.
    • Under "Software", click on "Advanced Settings".
    • Navigate to "Syslog", then "global" just underneath.
    • Change the value for "Syslog.global.logDir" to:
      Code: Select all
      [{localdatastore}] /scratch/log

      Where "{localdatastore}" is a local datastore on the ESXi host. A remote datastore can also be used but is not recommended.
      scratchsetting.jpg (65.26 KiB) Viewed 3038 times
    • Click OK to save the setting"
    • Logs should immediately start showing up on the datastore specified.
      esxilogs.jpg (76.38 KiB) Viewed 3038 times
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