In the message dated: Fri, 11 Sep 2009 14:37:46 PDT,
The pithy ruminations from Tracy Reed on
<Re: [lopsa-discuss] swap or no swap that is the question> were:
=>
=>
=> On Fri, Sep 11, 2009 at 10:18:47AM -0700, Shane Milburn spake thusly:
=> > 1. Would/Have you run a web server without swap? (they have 500Gb driv=
=> es
=> > in them so there's room for a swap partition.)
=>
=> Yes I would and I have. I would much rather httpd get hit by the OOM
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Ha! What happens if something else gets killed instead (sshd? iptables?
syslogd?)...then things get really ugly...not only is apache running badly,
but you can't login, or the machine is vulnerable, or you loose any logging of
what processes got killed by the OOM killer. I've had each of those things
happen, and it's not pretty.
=> killer when I can still login and restart it (or puppet/cfengine can
=> restart it) than to have the whole thing lock up or thrash swap to
=> death. With the price/performance difference between disk and RAM
=> being so huge I just buy enough RAM that I don't worry about swap.
I like the airbag analogy posted earlier...you never, ever want to use swap
space...but it's better than the alternative. Any use of swap is a signal to
buy more RAM or find out the underlying problem. Not having the swap in the
first place almost certainly means that a medium-sized problem becomes a really
big problem.
Mark
=>
=> --=20
=> Tracy Reed
=> http://tracyreed.org
=>
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