Quality of Service Agreement
Quality of Service Problem Discussion
The fact that virtual server hosting is a shared environment leads to concerns regarding quality of service. It is important to restrict and limit what applications are executed in this environment to ensure the actions of one user does not have a noticeable adverse effect on the performance of the server, and degradation of quality of service. These issues have been a main topic for many webhosting providers with the following common solutions:
1. Load Balancing: A user with excessively high system resource consumption is moved to a server with less demand on system resources, thus balancing loads among users depending on levels of demand.
2. Resource Division Tactics: A more popular approach, which divides memory, processor runtime, number of processes running, and does bandwidth-throttling right in the OS kernal.
The problem with the first approach is that this is a short-term fix to the problem. Eventually, all servers have heavy system resource demands and the websites hosted on the servers grow in the number of visitors. If much content is dynamic, then the problem escalates requiring fewer clients per server to maintain QoS, which leads to higher pricing to accommodate higher demands on system resources on the virtual server level.
The second approach automatically degrades QoS in an effort to control it! By the time the system resources are divided, each user may get 10MB of RAM, the "right" to use 10% of the 900MHz processor for 3 seconds every minute, and 112Kbps of bandwidth at all times. Such an approach does not allow users to burst when needed to take advantage of the server and network, which has now been reduced to a less power than the client's own PC on an ISDN line.
Needless to say, neither of the two common approaches above is satisfactory in our opinion. Neither addresses the problem with a long-term solution. Therefore, we have devised our own solution to this issue.
SNI LLC's Solution to Quality of Service
Our solution is that virtual server clients eventually evolve into dedicated server clients. Simply put, a virtual server solution is not scalable and not meant for a "high-volume" website with dynamic content, which requires an "excessive" amount of system resources. Rather than accommodating and degrading QoS, we encourage virtual server clients who meet this criteria (less than 3% historically) to move to a dedicated server, which is ideal for their needs. It is important for clients to understand that Quality of Service is lower on a virtual server solution than a dedicated server since it is a shared versus a non-shared environment.
Our Virtual Server Quality of Service Assurance
To ensure the highest possible ongoing quality of service, SNI LLC offers a Quality of Service Assurance to all virtual server clients. There are three areas which we address to ensure the highest possible quality of service possible.
Limiting Quality of Service Degradation
In accordance with our Acceptable Uses Policy, if we find that any virtual server client is consuming an "excessive amount of CPU and/or RAM", AND that client is having a noticeable, adverse effect on the performance of that particular server, than SNI LLC will immediately find and terminate the cause of such problem. These cases are usually poorly written Perl scripts, PHP scripts which excessively (>50 simultaneous connections) query the local mySQL/Microsoft SQL database server, and similar issues isolated to a single user.
If the incident is tracked to a particular user but the cause within the account is unknown, SNI LLC may immediately suspend the user's account without warning in the interest of maintaining Quality of Service for all other users on that particular server. While this policy may upset the offending user, the other 99.9% of our clients will appreciate the consistent Quality of Service. If the same user continues to degrade Quality of Service, then SNI LLC will ask that client to either upgrade to a dedicated server solution or find another hosting provider for their account.
99.9% Service Uptime Guarantee
Because SNI LLC guarantees a 99.9% uptime through What's Up monitoring software, it is important to ensure all monitored services (HTTPD, FTP, SSH, SMTP, POP3, RealAudio, JavaChat, and SQL) are not only "available" but also operational at all times. For example, a webserver which returns a "503" HTTPD response, which is a "Server Busy" error is not acceptable to the client. Therefore, there is a significant difference between a service being available "available to open a Socket" and operational (performing normally). SNI LLC guarantees all services to be operational 99.9% of the time.
Network Performance Monitoring
SNI LLC guarantees that at no time will our network traffic, both internal or external, become congested to the point of latency greater than 4 milliseconds going out of our network from our core router. Latency going out of our network can be tested at anytime via our traceroute utility. Furthermore, to substantiate our non-congestion claim on network traffic, SNI LLC makes all MRTG graphs to both transit bandwidth providers as well as long-haul circuits available for public viewing. Overall, we guarantee network availability 99.9% of the time per month.