In a recent
poll of nearly 2,000 DailyTech readers, worries about
performance seemed to be the biggest potential objection to broader
adoption of virtualization technology. Of the 1,998 respondents, 37
percent said they agreed with the statement that “virtualizing
slows everything down.” Smaller numbers cited lack of redundancy
(20 percent), complexity (12 percent), and cost (9 percent).
More than a fifth of the survey respondents – 439 readers, or 22
percent of the survey group – felt that there were no major
drawbacks to virtualization technology, voicing their support for the
statement, “Virtualization just rocks. Enough said.”
Several readers were vocal in their disagreement with the
perception that virtualization can trigger performance issues.
“Having worked with virtualization, I can say that performance
should be `almost’ a non-issue with virtualization nowadays,”
reader solgae1784 wrote in a comment posted to the DailyTech
poll webpage.
“I say `almost’ because there are a few applications that
(are) not suitable for virtualization,” solgae1784 added, noting
that in such cases “you will see `near native’ performance due to
overhead - even if the overhead is supposedly very small.”
DailyTech reader Mjello warned that running SQL on a
virtualized server can be problematic. “If you have any sort of SQL
on (the server), I’d urge you to not trust VM. If the server
actually fails completely, hot migration (won’t) work,” Mjello
wrote. “VM failover only works fully as long as the machine has
something to migrate from. Otherwise it’s like pulling the plug on
a normal server and then booting it again. Not a wise thing to do
with a SQL under load.”
Lack of redundancy is a nonissue with virtualization, according to
reader PorreKaj. “Virtualization can be expanded over several
machines. For example, we have a little blade center with four blades
running about 12 servers,” PorreKaj wrote. “If one blade blows
up, WMware will just automatically assign the virtual servers to the
other blades instantly - without interrupting the user.”
While DailyTech reader solgae1784 was generally bullish on
virtualization, he did offer the advice that users should think
carefully before choosing which CPU to place inside their virtualized
machines. “Be warned that newer CPUs are much better for
virtualization than the older CPUs,” according to solgae1784.
“The bottom line is, if you're going for virtualization, you may
need to buy new servers. Make sure you do your homework to see if the
initial investment will pay off in the long run. Then again, your
servers may be due for a hardware refresh anyways.”
