CPU issues with clustered hosting (Servage) / best practices to avoid high load?

Hello,

I’ve been hosting my WordPress website with Servage for about 3 years and lately, as of this month, I’ve been having problems with high load (which would normally happen once or twice a year). They just suspended me for two days and I am wondering if there’s any point in continuing or if I should switch to a VPS. The problem is – I don’t feel like moving and facing something even more uncomfortable, and on the other side, I wouldn’t want to get charged for anything either, as my site’s quite big and financed by its visitors, my own income is unstable.

So, I would like to hear sincere advice from people who are experienced with this, if possible. Thank you in advance.

Some basic stats and background:
I installed WP back when the current version was 1.2, in the summer of 2004.

The site in question is technically a fansite, but focusing on the subject’s work rather than crappy gossip. I offer audio files, news, streaming flv video and interviews & transcripts for people to read. There’s an image gallery, too. The site is completely ad-free.

The site gets about 3000 unique visitors a day. It has 1000-ish posts and 700-ish pages at the moment.

I do use custom slugs, but in the case of posts, they are NOT using the /%%postname%%/ syntax, for which I heard causes big issues.

The hierarchy of my pages goes up to four levels deep in some places.

I have only the basic feed and the comments feed and the

Out of external services, I use a counter on my other server, Google Analytics, IntenseDebate, TwitterCounter, ShareThis and, naturally, Akismet and WordPress.com stats.

I have Gallery2 integrated with WP through the WPG2 plugin. My gallery is a vital part of the site and it holds over 20 000 images.

My database size is around 30 Mb according to phpMyAdmin.

I have a second WP installation in a subfolder, housing a video site where some .flvs go up to 400 Mb and according to Servage, this isn’t a problem, they blame it all on plugins on the main installation.

Usual practices:
– I have disabled anything other than posts and Pages themselves from being indexed by search engines.
– I clean the orphaned options regularly.
– I optimise my WordPress database with frequency ranging from weekly to daily and I delete the logs created by Redirection and Lifestream, as they tend to grow quite big.

Last month, my site gained more visitors based on the events related to the person it’s about being all over mass-media and I got a high load warning on 17th December, even though twice as many people have been to my site on the 14th. Then everything was fine for a while and last Tuesday, despite the number of visitors going down to 3000-3200 a day and not much bandwidth being consumed, I got a high load warning around noon and my site remained suspended for eight hours. After this, I got rid of half of my plugins and cleaned out the orphaned options (there were no redundant rss hashes); but this happened again yesterday around 5 PM. Servage suspended me for two days and they said they’ll be forced to add a fee if this occurs one more time. So, as my site is quite big and Gallery2 isn’t very mobile, I would rather try to solve this issue first than go elsewhere.

Before I got suspended, I noticed that Twitter Counter won’t appear and that everything’s loading too slow all of the sudden.

A friend pointed out that someone he knows had a plugin cause a CPU overload on VPS with 1 visitor, said that the plugin was WP Security Scan and I deleted it through Servage’s control panel equivalent, and I also removed it from the options table. Then I wondered what other plugins might be causing issues and I noticed that WP Greet Box is known for high load as well and I got rid of that one, too.

Someone pointed out that edited pages left open in the browser can cause issues, too. How much of that is true? It makes no sense to me unless it’s about drafts/unpublished posts…?!

Someone also said that things like Twitmeme buttons (which I don’t use) or TwitterCounter (which I obviously do use) can contribute to high load, too?

In addition to all this, Servage are quite underestimating my knowledge and they attached 15-20 log entries to the notification about high load and suspension. I am obviously not an expert, but I am not mentally challenged either.

So, I am basically looking for a solution. I can’t afford too much experimentation and I would rather stay where I am, but Servage aren’t exactly elaborating on what’s wrong, they just suppose it’s a WordPress plugin issue, as they consider WP and G2 themselves to be reliable.

Any help would be more than welcome, just to reduce the load. Thank you, thank you, thank you. <3