Resource Usage Explained
Posted by on 27 November 2012 10:56 AM
* This article applies to our retiring CentOS 5/1h/Hive linux platform. If your hosting account is fairly recent, it is probably being hosted on one of our CentOS 6/CloudLinux platforms. More details can be found at https://support.arvixe.com/index.php?/Knowledgebase/Article/View/289/3/linux-hosting-resource-limits .
To avoid confusion and frustration, we want to ensure the limitations of our different hosting packages are clearly defined. This is expanding on our existing "how limited is unlimited" article which can be found here: https://support.arvixe.com/index.php?/Knowledgebase/Article/View/129/4/how-limited-is-unlimited
While we do not meter your disk usage or bandwidth, there are some resources which we must monitor and limit. Very high amounts of resource usage may require immediate action to be taken on your account to provide immediate relief (such as disabling the script, etc). If this happens, you will be contacted by one of our system administrators via email. We do not currently have tools to make monitoring of your Windows hosting account resource usage possible.
On our Linux hosting, the graph is split into two smaller graphs – the upper one shows the CPU time for your user. This is the average time a script started by your account takes to execute on the server. The time is in CPU ticks. The numbers on the left side of the graph show the number of CPU ticks and the digits at the bottom show the time on the server (the timezone on our servers is PST).
The lower graph shows the number of executions per hour your account makes. The numbers on the left side of the graph show the number of executions and the digits at the bottom show the time on the server (the timezone on our servers is CST).
A simple example of an execution is when a visitor opens your website and your index file is loaded. This counts as one execution. The more visitors your website has, the more executions it will generate.
You will also see two lines – a red and a blue one. The blue line shows the CPU usage and executions of a regular account on the shared server. The red one shows the CPU time and executions for your account. The higher the red line is, the more resources your account consumes.
High resource usage can stem from large amounts of traffic being received by your account, but most often is because of an out of date script, an improper configuration, or an abundance of plugins or addons that have been added to the script which should either be updated or disabled all together.
Automatic resource limits are put in place to protect the service that we provide our customers, to attempt to prevent a single customer from overloading an entire server. These are set very high where no customer should actually ever hit these unless extreme abuse is occurring from their account.
Shared Hosting - Linux (Personal Class, Business Class, Reseller Class)
MySQL abuse is the most common reason for servers at Arvixe to experience high loads or crash all together. Without proper throttling, it takes only a single out of control query to send a server over the edge. As such, we have the following limits across all of our shared plans to lessen the chances of that happening.
Where we draw the line:
Executions are how many times processes are run to serve your website. Every PHP page loaded and delivered from your site is an execution. Every video or audio file uploaded and/or converted is an execution. Every fetch process from your website is an execution.
With that in mind, here are the execution limits for your account:
Realtime CPU Usage is how many ticks your executions take. As mentioned in the article linked above, ticks are CPU seconds. 1 tick equals 100% of a single core for 1 second. For a server with 24 cores, that means that there are 24 ticks available in a second on that server.
The following limits are currently in place for Realtime ticks:
Queries are when your website "queries" your database. Each page execution can have multiple queries, sometimes even to multiple databases. Most queries complete in a matter of milliseconds, but really large ones can take minutes to finish. Because of the very variable nature of MySQL queries, this section will expand beyond a simple count of queries once the proper metrics have been tested and put in place.
The current MySQL query limits for your account are:
To put this in perspective, the personal class plan can deliver 3 pages per second running full tilt for 10 hours straight, each of those 3 executions using 1 full second of CPU time, and making 10 database queries, and all before being flagged for over-usage. Looked at another way, that is 1 page view every single second of an entire 24 hour day.
If your account exceeds these limits, you will not instantly be suspended nor even severely limited. Everybody has to deal with a rush sometimes, and your sites are no exception. Our system will notify you that your account has exceeded the set limits, try to slow your executions down, and check again in an hour. If your usage falls back to within limits, all restrictions will be removed and on with business. Only after 3 successive abuses will a suspension be issued, and a request sent to investigate your usage.
Shared Hosting - Windows (Personal Class ASP, Business Class ASP, Reseller Class ASP)
VPS Hosting (VPS Class/VPS Class ASP)
As resources are dedicated using virtualization technology, you are allowed to use 100% of your CPU, memory, and process resources. If you are looking for more CPU resources than a Shared Server, you will NOT want to pick VPS; instead, you should choose a Dedicated Server.
Dedicated Hosting (Dedicated Servers)
As this is a dedicated hosting environment with no artificial/virtualized limits, you are allowed to use 100% of the server's CPU resources, memory, and processes, as it would have no impact on other customers.
SERVERS CAN NOT BE USED FOR MAILING LISTS/BULK MAILING.
VPS and Dedicated servers are free from this limit.