[BlueOnyx:09878] Re: Memory Usage

[Matthew James]

Thanks, everyone, for the help!  I'll plan on upgrading the server soon.

-
Matt James
President
Flat Cap Apps
http://www.flatcapapps.com

On Mar 20, 2012, at 11:46 PM, Chuck Tetlow wrote:

> Matthew James wrote: 
> > > The system overall has 512MB of memory, which I know is not much, 
> > > however, there's not much running on the box at this time either. 
> > > 
> > > When I go into /top/, I see the following stats: 
> > > Mem: 509084k total, 426320k used, 82764k free, 8668k buffers 
> > > Swap: 262140k total, 262092k used, 48k free, 212316k cached 
> > > 
> > > However, when I look down the list of processes, only spamd is taking up 
> > > any memory remotely high -- 9.1%.  All other processes are showing less 
> > > than 1% usage (usually far less).  Also, the load average on this server 
> > > is almost always below 1, so I'm not sure what the repercussions are for 
> > > letting it ride with memory warnings like this.  It doesn't appear to be 
> > > having a noticeable affect on performance, however, right now it's only 
> > > really being used by a few people. 
> 
> 
> > Look at all the Swap that the box is using... it's choking! 
> > 
> > 512MB RAM for any modern box, esp if you're using any dynamic sites 
> > (PHP, MySQL) is really quite low.  I would not be surprised to see 
> > performance hits given the specs. 
> > 
> > So now what is happening is you're draining the available RAM and 
> > swapping memory to an extremely low performance disk (remember, you're 
> > sharing that disk throughput with however many other users doing 
> > goodness knows what.) 
> > 
> > We charge $10 more per month, but our minimal BlueOnyx VPS has 4 CPU 
> > units and 1GB RAM and 500GB transfer.  I certainly would not recommend 
> > more than that, and that is why we don't offer less than that. 
> > 
> > -- 
> > Chris Gebhardt 
> 
> 
> I agree with Chris - 512Meg of RAM is ridiculous for a virtual hosting server.  Especially when you state you are running SPAM Assassin (spamd).  That's a memory hog, and you've barely got enough memory for the box to run without SPAM Assassin. 
> 
> All the BlueOnyx servers I set up for hosting customers will have 1Gig RAM minimum.  And if they're going to use SPAM Assassin, or any other resource hog - that's bumped to 2Gig minimum.  I've seen BX servers with just 512 Meg RAM - and they just can't handle much.  Two to five small sites without much traffic, e-mail, or SPAM filtering is all you'll be able to do.  Anything more, and its going to be caching all the time - as Chris pointed out your box is doing. 
> 
> That "top" output shows you're using 262Meg of cache (and that's all the cache there is.  A mistake right there - always configure at least two to three times the cache as you have in RAM).  Oh, and the reason the processor load is low - its always waiting on the cache memory!  Its constantly waiting on data reading/writing to/from the hard drive - and that's why the CPU load is low. 
> 
> I suggest you try adding another 512Meg to 1Gig to your server and see how much it speeds up!  Add enough that when it finishes booting up, the "top" output shows no cache usage (no more than a 100K or so at most - and that shouldn't change as you watch it).  If its having to use cache right after boot - you still don't have enough RAM. 
> 
> 
> 
> Chuck 
> 
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