Understanding Server Load

Hi there,

I have googled and googled and am still not understanding "Server Load".

Like right now, ours is:
Server Load 6.20 (2 cpus)
(I think this is bad) :speechless: Maybe even VERY BAD.

And in my vBulletin it says:
1.99 2.93 2.72 | 130 Users Online (84 members and 46 guests)

And, so, if we move to a dual core or quad core machine, does it help with these things?

 

I've never understood these numbers, either.

But I can tell you that you're already on a dual-core machine (2 cpus).

 

Sounds right to me. Server load with dual processors is about 6, vB says about 3. Going to quad would give 1.5 server load on vB. At least that is my understanding.


Anyone else?

 

Does increasing RAM help alleviate server load?

 

Hi ;D

I just check my server load... Server Load 0.00 (8 cpus) so I would say the more cpus your server has, the lower the numbers are which should make the site faster?

My ram is at 35% and server load is 0, so I doubt ram has much to play with it. But I'm not that sure.

 

Okay...

A server load of 1.00 means that the CPU core is at 100% utilization. If you have multiple cores the 100% utilization is 1.00 X number of cores. So 100% utilization for a dual core server is 2.00.

The numbers are in order listed as 1 minute average, 5 minute average, 15 minute average.

Having a load over 100% utilization is not bad per se. A lot of things can back up the CPU. Technically it can only do one thing at a time. However it does those things so quickly that it gives you the impression it is doing multiple things. The problem arises when your machine gets sluggish and stops responding or is over the 100% utilization constantly. If you look at many shared servers, they are running at 20.00 or even 50.00 load and yet are still somewhat responsive. It isn't uncommon to see your server load jump to over 10.00 and then drop to less than 1.00 in the next 5 minutes.

Adding CPU cores also does not double the processing power of the core before it. You can only feed so much RAM, Addressing, Disk I/O and other data into those cores so you don't get 100% benefit just by adding cores. Each CPU core only adds about 80% of the processing power of the previous core in reality.

The best bang for your buck in increasing performance of your servers are:

1) Optimizing your software. This often isn't possible on shared or semi-dedicated plans because your implementation isn't virtualized and you don't have root access. However programs like Apache, MySQL and even PHP are not very optimized at their initial installation. They are configured to run on millions of platforms, not your platform. Please note that using Hardened versions of these will increase security but will also decrease performance. You will need to choose between maximum security, optimal performance or a balance between the two.

2) Updating your software from 32-bit to 64-bit will bring performance and stability. It also doubles the number of addresses available to the CPU. So if you have a dual-core CPU, use 64-bit software.

3) Increasing your network bandwidth. Most servers are on 10 megabit connections. Good old inexpensive CAT3 cabling. They could also be hobbled with a 10 megabit hub even if they are using CAT5. Always make sure your server is on an Asynchronous Switch and not a hub. Switches are faster because they are smart. Make sure your hosting provider uses a 100 megabit or 1 gigabit internal network. Though most charge extra for the higher bandwidths.

4) Increasing RAM. With modern OSes, you should probably have at least 4 Gigabytes of RAM for the first two cores and 2 GB for each additional pair of cores.

5) Improving Disk I/O through either caching, better disk speeds, smaller platters configured in RAIDS, etc... 500 GB and 1 Terabyte drives are great for data storage but you want small fast drives for your applications. You can simulate some of the benefits of a RAID if you can't implement one by using separate disks for OS, temporary data storage and data storage. Separate partitions on the same physical drive give little to no performance increase.

6) Finally, upgrading your CPU. Provided your system can support moving from a dual-core to a quad, octo or hexa core processor than you can upgrade the CPU. You should upgrade your RAM as listed above at the same time. Though most hosting providers don't have machines that support more than 16 Gigabytes of RAM.

 

Any updates on your server? Is your site up and running ok and can people find it alright?

Did you need to switch hosting providers?


Besides just being curious, I'm trying to learn more about these types of things.

 

A server load of 6 with 2 CPU's (dual core or two physical CPU's?) isn't horrible, in fact it's not bad at all. I've taken my quad cores up to 100+, now that is bad!

What Wayne said is pretty much a decent description of server load itself, and his advice is pretty decent re: solving the problem, however adding more resources doesn't really solve the problem, it just gives more room for the problem to grow. Think of it this way:

If your sink continually drips and is about to fill up, would you solve the problem by fixing the drip, or by getting a bigger basin? By getting a bigger basin, you don't solve the real problem, you just give it a bigger area to flow into.

Figure out what's causing the CPU overload and resolve that.

 

Thanks for this Wayne, very useful information to know.

 

We ended up moving to a much beefier machine, it is a Core i7 920 cpu. So far, the site is running much better and the server load is always below .5

It's pretty fantastic.

Thank you for asking.

 

That is great news! Thanks!

 

Server Load 1.18 (8 cpus)
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Thats my load, is that bad? Im new to this hosting stuff.

 

No. It would need to be over 8 to start getting into the bad area.

 

Okay heres my updated one.
----------------
Server Load 0.57 (8 cpus)
----------------
After i did some stuff it dropped.

 

We had 333 users today on the forum and our server really slowed down SO much.

It's kinda sad, we had 600 online when we were on shared hosting and now we are dedicated and ... :shrug:

How do forums that have a few thousand on a time do it?

 

You need a mechanic. Some one that can communicate with the people at vbcom for various settings on your server.

 

Your bandwidth will play into some of that response time. See if you can check out your usage and how it coincides with the slow response time you experienced.

Might be part of your puzzle if indeed everything is configured right on your DS for such usage.

 

FastCGI, opcode cache, memcached, a highly tuned database configuration, InnoDB, and custom-compiled php.

And server load is not just about processing power. Forums hit disk I/O hard. I have a RAID 1 to help with that.

 

It's far from easy, let me tell you that much.
How is it handled? Multiple www entries across multiple servers, splitting off DB, mail and WWW servers, and all around load ballancing.