AJBERGH
Contributor
Contributor

ESXi Loss of Boot LUN, Expected Behavior?

I have a client that is asking me to test a particular scenario in my
lab. I thought I might ask the community to see if anyone has tested this.

My client wants to know what happens when ESXi 4.1 loses complete
access to all paths of its FC boot LUN. A quick test showed that ESXi
remained up and stable. My assumption is that because ESXi runs mostly
in memory and that once booted does not look to its boot LUN all that
much.

What events would cause ESXi to crash while running without access to
its boot LUN? VMotion? DRS events? What events would cause ESXi to
write to disk? Would attempting to write to disk crash ESXi if the
boot drive were unavailable?

Thanks in advance.

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2 Replies
Josh26
Virtuoso
Virtuoso

Usually your boot LUN is your logging directory, so obviously logging will stop.

Configuration is backed up every 90 minutes. If your boot LUN fails, you will lose any configuration changes that you make that don't get backed up.

The server will however, continue to function, for as long as all data LUNs are available.

AJBERGH
Contributor
Contributor

I did some additional research and came upon the following two articles that help clear this up:

An article on how often an ESXi server writes to the boot disk:

http://blogs.vmware.com/esxi/2011/09/how-often-does-esxi-write-to-the-boot-disk.html

The official information regarding the scratch partition for logs on ESXi.

http://blogs.vmware.com/esxi/2011/07/after-you-migrate-tips-on-working-with-esxi.html

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