[LRUG] Server capacity

[Gerhard Lazu]

80% is considered optimum capacity. You're not maxing out the server and
you're not wasting resources either. That's what VPS & cloud providers mean
when they say "we're so green that Amazon is a desert in comparison".

CPU and memory are not as much of a problem as disk usage. Disk iowait is
one to watch on shared disks. If your disks are doing anything above 5
%iowait (iostat -m 2), you're pushing them too much. sysstat with sar is a
good one to have. A lot of the time, when you're CPU usage is high, it's
usually network & disk iowait that are the root cause.

Put background jobs onto another machine, simple as. Heroku gives you 1 bg
worker for free. Each extra worker costs $0.05/h. As a rule of thumb, you
don't want to mix the *now* with *whenever*.

Gerhard

------------------------------
Twitter <http://twitter.com/#!/gerhardlazu> Github<https://github.com/gerhard>
 Blog <http://gerhardlazu.com/>


On Mon, Mar 12, 2012 at 4:11 PM, Andrew Stewart
<boss at airbladesoftware.com>wrote:

> Hola El Rug,
>
> What sort of capacity do people run their servers at?
>
> I have a Rails app on a 1-core Ubuntu 10.04 VPS with 1GB RAM.  Everything
> runs on that box: web server (Nginx), app servers (Unicorn with 5 workers),
> MySQL, background jobs etc etc.
>
> The RAM usage hovers at around 75%.  I want to make the most of what I've
> got; is 75% too conservative?  Adding another Unicorn worker would take the
> RAM usage to about 85%.  I wonder how much memory it's sensible to use up.
>
> Another thing: from time to time the app renders big PDFs with Prawn, and
> when this happens the CPU is maxed out for potentially several minutes,
> adversely affecting responsiveness.  What's a good way to address this?
>
> Thanks in advance.  Sorry this isn't a job ad ;)
>
> Cheers
> Andy Stewart
>
> -------
> http://airbladesoftware.com
>
>
> _______________________________________________
> Chat mailing list
> Chat at lists.lrug.org
> http://lists.lrug.org/listinfo.cgi/chat-lrug.org
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.lrug.org/pipermail/chat-lrug.org/attachments/20120313/16fe8ee3/attachment-0003.html>