Is there a possibility this is related to the similar sounding reboot issue
earlier in the month?

Quoting Sun, May 10, 2009 at 6:42 PM:

"...at approximately 17:00Z unfortunately all VPSes ended up being
 hard
shut down (roughly equivalent to a power cycle), and then
being
unable to restart them meant that a reboot of the server was
required.

"All VPSes on faustino were up and running again by approximately
17:16Z.

"As to the root cause of the issue, there is very little to go on.
Nothing useful was logged as regards the initial issue, although I
have now at least learned not to attempt to restart one particular
daemon in future."

Quoting Mon, May 18, 2009 at 1:37 PM:

"Last night at approximately 01:40Z faustino was power cycled.  It
wasn't done by me, and on talking to the colo provider it seems only
this machine in the rack was affected and nobody was working in the
rack at the time.

"As a result all customers on faustino experienced a hard reboot at
around that time.

"I've been trying to discover how/why this happened but there is
nothing suspicious logged, so I'm having a hard time.  Obviously I
do suspect a hardware problem and will be keeping a close eye on the
server."