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May 10th, 2007 [by Doug Alder]
What exactly is it that a infrastructure provider is promising you when they tell you that you have a , and what does it mean? If you have not already done so please read Understanding as a primer for this article. purchase from carriers typically on a 95th percentile with a certain “commit” level or as a second option they purchase bandwidth on a “capped” model. (Although it is possible to purchase on a “volume” or GB usage model this is not a standard way of buying bandwidth in a model.)RackForce offers the Carrier version of the capped rate model; for example, our dedicated 10 Mbps connection is capped at 10Mbps. This is the peak rate of the bandwidth that can be used at the server or VPS. Whether the server plugs into a 100 Mbps or a Gigabit switch port is irrelevant as the real concern is always how congested is the switch port and not what is the maximum rate or capacity of that switch port.So, that begs the question, what is congestion in this instance? The definition of congestion is based on the 95th percentile, the average sustained rate divided by the port maximum rate equals the percentage of congestion. So you could have 20, 30, 40 or more 10 Mbps servers plugged into a 100 Mbps port as long as your port congestion is within acceptable limits. RackForce believes that should be no more than 40%. That number is very important. In TCP/IP networks there is packet overhead and once you reach about 60% of capacity on a connection you start to get packet contention and from that packet loss and that leads to poor network performance.For example if there are 30 servers, each with a dedicated 10 Mbps port, all connected to a 100 Mbps switch, the lineal math calculation is 30 X 10 = 300 Mbps, but the actual average usage on that switch, expressed as a 95th percentile, may only be 30Mbps. The Carrier (data center in this case) will monitor the switch port and if the average sustained usage is 40 Mbps or higher (40% congestion) the port capacity will be increased (if the Carrier uses a 40% congestion rate policy) or will move customers to reduce the load.Check with your data center/hosting provider to see what they offer for this. If it is more than 40% consider moving your business elsewhere.In summary, how does this apply to RackForce? We employ a Carrier model of capped rate, which is a dedicated unmetered service from the switch port to the server. Beyond that, the Internet and Ethernet switching is actually a “shared” bandwidth model in general (not withstanding sophisticated architecture like MPLS, but that is not applicable in data centers); a Carrier or ISP will monitor port congestion to ensure quality of service. Most offer a 60% congestion guarantee, RackForce offers a 40% guarantee. If a port has been identified over the 40% congestion then we take appropriate action. Quality servers, quality network and quality service is what is all about.
May 11th, 2007 at 1:20 pm
i’m developing a social networking website like myspace and friendster…and going to get it hosted soon. But I’m a newbie in hosting, hence would like to seek your expert advice.Initially the site would be like myspace minus the multimedia content (video and audio). The site consists of 10++ pages and mostly are text content. Also, there is a photo album function allow user to upload and share photo.I’m going to deploy 5 servers (1 web server, 3 application server running java and tomcat, and 1 db server) I’m thinking to allow 5000 ppl to sign up during the initial Beta launch. Assuming there are 500 concurrent user active at one time.Based on your experience, how much bandwidth required for a website with the above setting ? I’m thinking to get a 10mbps dedicated line but I’m afraid it’s insufficient. What is the normal price range for a 10Mbps dedicated unmetered line package?Can you recommend some software that can derive the Http bandwidth for a site ?Thanks
May 11th, 2007 at 2:16 pm
Hi DerekThat sounds like an interesting project. I’ve discussed this with our system administrator as well and we both think you should consider a different network configuration. Can you get by with two application servers, or could you add one more server to your mix?The reason I ask is that you’re right 10Mbps going to a single server is probably not going to work. What we suggest doing is going with two load balanced front end webservers, each with dedicated unmetered 10Mbps connections. This will easily handle the 500 concurrent sessions and quite a few more. As you site grows you can add more load balanced webservers to handle the load.I recommend our 5300 quad core servers for the web and app servers (the 10Mbps connection is included in the price) and our 5350 (up to 12GB RAM, dual quad core cPUs, up to six drives,RAID 0, RAID 1, RAID 5, and RAID 1+0 available).
One thing else you should give some consideration to. Regardless of whether you want Linux or Windows servers you should consider adding a virtual layer to your servers and operating from inside that virtual environment. This is RackForce’s DDS strategy. The value of this for you is enormous as it makes all your data extremely portable. For example if you start out on a RAID 1 server and find you need to move to a RAID 5 server it is a heck of a lot easier as RAID is at the hardware level outside of the virtual environment and all that’s needed is to move the virtual hard drive file to the new server.Give me a call on Monday Derek and we can discuss this in more detailRegardsDoug AlderSales ManagerRackForce Networks Inc.Network and Infrastructure On DemandToll Free (North America): 1 800 941-1921 Ext. 2301International: 1 250 717-2340 Ext. 2301Website: http://www.rackforce.comSupport: https://support.rackforce.com
May 12th, 2007 at 2:31 am
Hi Doug,Thanks for the prompt reply. I really appreciate your professional advice but I’m afraid to disappoint you cause I’m from Malaysia.The way you reply and your suggestions are far more professional than our local counterparts. However, I have no choice but going for local hosting provider cause I’m deploying my own servers.Again, thanks for answering my question, I’ve learnt a lot. Now I know that a single 10Mbps connection will not work for my site.I’m really impressed by the way you answered my questions. Did you ever think of extending your business to Malaysia ? I’m pretty sure that I’ll get my site hosted with you guys if you have local presence…