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Web Hosting - Bandwidth and Server Load, What's That?
Two key performance metrics will impact every web site owner sooner or later: bandwidth and server load.
Bandwidth is the amount of network capacity available, and the term actually covers two different aspects. 'Bandwidth' can mean the measure of network capacity for web traffic back and forth at a given time. Or, it sometimes is used to mean the amount that is allowed for some interval, such as one month. Both are important.
As files are transferred, emails sent and received, and web pages accessed, network bandwidth is being used. If you want to send water through a pipe, you have to have a pipe. Those pipes can vary in size and the amount of water going through them at any time can also vary.
Total monthly bandwidth is a cap that hosting companies place on sites in order to share fairly a limited resource. Companies monitor sites in order to keep one site from accidentally or deliberately consuming all the network capacity. Similar considerations apply to instantaneous bandwidth, though companies usually have such large network 'pipes' that it's much less common for heavy use by one user to be a problem.
Server load is a more generic concept.
It often refers, in more technical discussions, solely to CPU utilization. The CPU (central processing unit) is the component in a computer that processes instructions from programs, ordering memory to be used a certain way, moving files from one place to the next and more.
Every function you perform consumes some CPU and its role is so central (hence the name) that it has come to be used as a synonym for the computer itself. People point to their case and say 'That is the CPU'. But, the computer actually has memory, disk drive(s) and several other features required in order to do its job.
Server load refers, in more general circumstances, to the amount of use of each of those other components in total.
Disk drives can be busy fetching files which they do in pieces, which are then assembled in memory and presented on the monitor, all controlled by instructions managed by the CPU.
Memory capacity is limited. It's often the case that not all programs can use as much as they need at the same time. Special operating system routines control who gets how much, when and for how long, sharing the total 'pool' among competing processes.
So, how 'loaded' the server is at any given time or over time is a matter of how heavily used any one, or all, of these components are.
Why should you care?
Because every web site owner will want to understand why a server becomes slow or unresponsive, and be able to optimize their use of it.
When you share a server with other sites, which is extremely common, the traffic other sites receive creates load on the server that can affect your site. There's a limited amount you can do to influence that situation. But if you're aware of it, you can request the company move you to a less heavily loaded server. Or, if the other site (which you generally have no visibility to) is misbehaving, it's possible to get them moved or banned.
But when you have a dedicated server, you have much more control over load issues. You can optimize your own site's HTML pages and programs, tune a database and carry out other activities that maximize throughput. Your users will see that as quicker page accesses and a more enjoyable user experience.
Web Hosting - Managing Disk Space Few things are less exciting than managing the disk space that always seems to be in too short a supply. But few things are more important to the health and well being of your site. The most obvious aspect of managing disk space is the need to have enough. If you have only a few dozen web pages, that's not an issue. But as the amount of information (web pages, database content and more) grows, the quantity of free space goes down. That's important for two reasons. All permanent information on a computer is stored on hard drives. Temporary information is often stored in memory only. The two components are completely separate, though they are sometimes confused with one another. As the amount of free space on the hard drive decreases several effects occur. Here's one way to picture them... Imagine you had a table with a certain area and you lay out playing cards on the table. At first, you lay them out in order, the 2 at the side of the 3, then 4, and so on. But then you pick up one or two cards from the middle and discard them. Then you add some more cards. Pretty soon things look pretty random. Now cover the cards with a big opaque sheet of paper. You want the cards to appear in order when displayed to someone. A special robot could be designed to always pick up the cards from underneath the sheet in order. Or, it could slide a hole in the sheet over the cards to display them in the correct order (2, 3, 4, ...), no matter what order they are really in. That's similar to how the operating system always shows you information in a sensible way, even though it's actually stored randomly. Why should you care? Real files are stored in pieces scattered around the drive wherever there is space for them. The more free space there is, the quicker the operating system can find a place to store a new piece. That means, if you delete the junk you no longer need (and free up more space) the system actually runs quicker. It helps create space you might need, and allows the operating system to store files for you faster. But there's a second effect. As you delete old files or change them, the pieces get more and more scattered. It takes the 'robot' longer and longer to fetch or display the 'cards' in order. Existing files are fetched and put together 'on the fly' (say, when you request a graphical page or a list of names). But, it takes longer to put together the web page when there are more scattered pieces. So, the other aspect of managing disk space is to keep the pieces of the files more or less in order. A utility that does that is called a 'de-fragger' or de-fragmentation program. You can request that a system administrator run it, or if you have the authority, you can run it yourself. That keeps the 'cards' in order and allows for quicker access to them. So, managing disk space involves chiefly three things: (1) keeping enough space to store what you need to store, and also (2) keeping enough free space to make new file storage quick and (3) making old file retrieval fast by keeping things orderly. When only a few files are involved the benefit isn't worth the effort. But as the number and size of the files grow, to thousands of files or several gigabytes of data, the effect becomes more noticeable. Keeping things organized then makes a significant difference in performance. Much of this can be automated using utilities. Some will delete files in a certain folder older than a certain date. A de-fragger can be set to run automatically during times of light usage, or quietly in the background at all times. Discuss the options with your system administrator and help him or her do the job better by keeping your house in order. You'll benefit by having a better performing web site. Web Hosting - Email Issues When you build a web site, you often provide a means for users to communicate with you. One of the most common 'add-ons' to a web site is the addition of some kind of email access. Email is used to sign users up for newsletters, provide communication for administrative issues and a hundred other uses. But, as everyone sadly knows, email problems can occur. Virus infection is among the most common, though the situation is actually better today than in the past. Huge efforts, and some progress, has been made over the past 10 years to reduce the number and severity of virus attacks. Hackers haven't surrendered, far from it. But they're on the defensive like never before. Many of those viruses were (and are) spread through email, usually in the form of email attachments. That's the source of the now-common advice never to open an attachment from someone you don't know. Professionals will often extend that advice to suggest you never open an attachment that's unexpected, even if it's from someone you know. Well-meaning, but computer-challenged friends often accidentally forward virus infected emails. Spam has taken over the top spot for email annoyances. It's estimated by various different professional sources that 92-97% of all email sent today is spam. While the definition varies, spam is generally regarded as any unwanted commercial email sent by someone whom the recipient doesn't know or have a business relationship with. Spam clutters email inboxes, requires people to sift through to find valid messages, and often contains offensive messages in some form. But, it's a fact of life and isn't going away anytime soon. Even though laws are in place, thousands of spammers continue to risk fines or jail for the chance of making money from that small percentage who will open the unwanted email. Other forms of email problems are even more severe for many web site owners. When the mechanisms fail that they rely on to send and receive messages to and from their users, that's a problem. Dealing with those problems can range from sending an email or instant message to an administrator, to tracking down the right person to get your site removed from a blacklist. Email is the communications vehicle of choice for millions everyday. When the system burps, someone has to take time to do something about it. Often, that means relying on a person who is already overburdened with too many issues to resolve. So, besides pointing out some sad facts or complaining, what's the point? All of the above shows just one more area you should look at when selecting a web host or deciding whether to move to another. Just as with server or network administration, companies vary in their ability to deal with email-related issues. Some are responsive and super-competent. Others, are simply indifferent or worse. And many are in between. Email administration, like server maintenance or network management, is a professional specialty. Skill in one does not necessarily mean quality work in another. Finding a web hosting company and/or system that has few email problems, and solves them quickly when they occur, is an important task. Spend some time researching who provides superior support in email. You'll be happy you did. |