Downtime with WordPress

I keep getting downtime on my site. I have done everything to try to speed up the site – installing and setting up W3 Cache plugin, using Google PageSpeed to optimize page loading times (80/100 at the moment).

I get very little traffic to the site. I’m on a VPS with 600MB RAM and I keep on getting downtimes of over an hour because the PHP scripts spike over the RAM allocation.

As you can see there is a huge spike here. There was no extra traffic at this time, although I may have uploaded a 20MB file at that time but I can’t believe that caused it.

All I get from support about these issues is to

look at the following to
optimize your WordPress installation:

but I’m not so good with server side technologies to be able to look in more detail as to what’s causing these spikes.

Can anybody help?

Do you have a cronjob set up for 7 pm?

Just out of curiosity, with such a low use of resources, why use a VPS? Surely you’d get the same service from shared hosting? I only ask because I might move to VPS someday, but I can’t justify it with the amount of resources my site currently consumes.

Hi bobocat, no cronjobs set up.

I got this from Support here.

Regarding your VPS RAM, in general any site that gets about 15,000 hits
needs it’s own VPS server with 300MB of RAM. Since you are getting close
to 3x that amount, the general rule would be that you need about
900MB-1000MB for your VPS. That would allow you to run your sites without
any issues.

I have been asking for the optimum amount of RAM for sites with usage such as mine and now I finally have an answer.

I’m not sure if I need a VPS but I decided to go for one after similar problems of outage on various shared servers I’d been using. This is why I’m trying to get rid of all downtime from my sites now.

Thanks for your reply. That’s very interesting information.

It’s also interesting that they are willing to give a clue as to what the secret CPU threshold is for shared hosting, although couching it in terms of hits is quite ambiguous. They state on the wiki that sites can use up to 300 minutes if they are optimized, but then just below say that the average is 5 minutes per day.

I’m sure 15,000 flat html files causes a much lower load than 15,000 WP hits, so their response is very vague.

By the way, do they mean 15,000 / day? / hour? / min? or what?


Hello bobocat. I’m sorry it’s taken me ages to reply, I thought I was subscribed to this thread but apparently not.

I’ve been through all the emails from them and they didn’t give a timeframe for the number of hits. I have 9 WordPress sites on it that have maybe 1500 visitors a day altogether. I hope that helps.

I’d asked the question (how much RAM do I need for a certain amount of usage) many times before I got an answer. :slight_smile:

FWIW, I think that this is an impossible question to answer via the forum because there is no way to analyze what you are actually doing… for example in your first post we were talking about “a site” as in ONE site… now we find out that your are talking about 9 sites on one VPS!

also for FWIW…all wp “sites” are NOT created alike, especially with wordpress… all the various plugins can cause the site to behave differently…

it greatly depends… if 15,000 hits come evenly distributed over X… with X being a day or a week then there is one answer, but if all 15,000 hits come at 7PM in a 5 minutes window then the answer will be entirely different answer…an answer that will waste alot of rsources for 23 hours and 55 minutes just to cover the one 5 minute period that gets all the traffic.

That example is not real-world but given to illustrate the point that how the traffic is distributed also affects the answer.

If i were you, nne thing I might try to get to the bottom of this is to edit robots.txt to find out if the search crawlers are indexing too much too often.

There is a double edged sword there however, if your posts are “trending topics”… one the one hand you want the crawler to find the new content quickly (which means you don’t want to issue instructions via robots.txt to only come back once a week) , on the other hand if your site is huge, you don’t want the crawler coming back and re-indexing the sites in total every 24 hours.

I see your choices as being 2-fold-- either analyze your traffic and understand it, and try to fine tune the bot traffic


follow the recommendation that support already gave you and raise your 600mb VPS to 900-1000MB…

Interesting topic, like to follow this one.
I just opened a blog (change from a static website) and went live end june.
It has on average between 1000-1500 hits a day.
That is not visitors, but hits, which is what DH means.

I have no VPS (yet), but my stats plugins do not report any 500 errors (404 pages).
I also have W3 total cache and I use Amazon/Cloudfront/S3 for 1000’s of pictures to be preloaded.
No visitor/member has yet complained the site is offline and Pingdom tells me I am constantly online.
My Google rating is 91/100

I have learned that with W3 it is best to NOT use the minify option, because it creates more problems then advantages.

I was a bit worried, that maybe I needed VPS, but I guess all runs well without it.
Now after one week the first peak of going online is past, so I expect to have no problems and do not need VPS.

Note about upload a 20MB file within wordpress. WordPress uses php/script and that always causes the peaks, best is to just upload by FTP and just set the URL manually in you page/post.
If you are worried about WP touching the html code (which is does and is very, very annoying, use the plugin “Always Edit in HTML” works perfect (if you understand html and can write/edit it)

Regards, Ron