Signal Tower - A new visual alerting feature

With the release of 7.13 earlier this morning, we have introduced a new alerting hardware feature.

The 26cm tall signal tower enables to visually indicate the status of the monitoring tasks performed by the ServersCheck Monitoring Software.

The tower will either show a green, amber or red light. On failure it can also flash a red light to stress on the situation.

On top of that it can also generate an audible alert of 85dbs measured at 1m distance. This will ensure that detected failure will not get unnoticed.

The tower is available in 2 versions:
- CE Certified for the European Union with an European style power plug (220V)
- FCC Certified for the North American market with a 2 pin straight US power adapter (110V)

The towers are available for order. A 2-3 weeks lead time has to be taken into consideration.

Technical information on the Signal Tower can be found on following url:
http://www.serverscheck.com/hardware/signal-light-tower_phe-3fb.asp

ServersCheck in French Polynesia

Our company's strategy has been since inception is to take care of cultural differences. This resulted in having our software available in more than 30 languages, pretty unique in our market space.

We have a "Think Global, Act Local" approach. While having a standard solution almost world wide, different markets ask different approaches. Rather than opening offices in all countries of the world, we rather team up with local players in different markets.


Our market coverage is now almost world wide as through the partnership signed with 17s149w in French Polynesia, we are now represented in the Pacific region. This emphasis our believe in not only the traditional big markets where everyone is active but also the smaller markets.

I was quite surprised to hear that only one of the Big Three had a local presence in French Polynesia while speaking to a prospect. He was quite pleased to hear that ServersCheck took interest in this market as well and had partner with an innovative company like 17s149w.

You can visit our French Polynesian website at http://www.serverscheck.pf

Through our French Polynesian partner, all islands & countries in the Pacific can now turn them to a local contact that is able to assist them regarding the ServersCheck products.

Monitoring a website

A question we often get is: how do I monitor a website.

One has first to understand the different layers involved in a website and to what info he has access.

1. Hardware level:
A simple PING check will reveal if a server is alive or not. Monitor the response times as slower response times might indicate an error

2. OS level:
if you can then you can use the WindowsHealth or LinuxHealth check types to monitor the general health of the host running the site. This may help you to avoid situations like full dis, low memory resulting in a website failure.

3. Web server level:
A website runs on a machine, that hosts an Operating System and that has a web server. The site itself can be static or an application running as a layer on top of the web server.

A web server is typically monitored by using the TCP check to see if the server responds on the defined port (by default 80 or 443 for HTTPS)

4. Web application level:
The fastest check is to perform a HTTP HEADER check that verifies the header data sent back for a specific URL

The best option though is to use the HTTP check. It will load the given page and then scan the content to see if a predefined string is returned. If not, then an error is triggered.

You can also monitor the page download time; this is the time required to download the HTML - excluding images and any other embedded content.


Depending on your level access to your web site and server, you can define multiple layers of monitoring.


With ServersCheck you will know when your site fails before your customer(s) start calling you that there is an issue.

Email as best alerting option?

While getting through our Web Analytics reports, one thing that surprised me is that most people seem to be interested into a server monitoring software or environmental sensors with email as alerting capability.

Monitoring is not only detecting when something goes wrong but also making sure that you receive the alert when something like that happens.

Almost any competitive product on the market supports email alerting as it is the most basic way of alerting.

Unfortunately most customers are happy with this most basic way of alerting without realizing the potential risk of it. Some go a step further by having the email forwarded as a text message or on their PDA / Advanced Cell Phones.

Bottom line remains the same though: email requires network connectivity.

If your network is down, then your email alerts will not help you much. You will not get alerted and know that something serious is happening.

Therefore we stress on the fact that you should consider using SMS alerting using a GSM modem. I want to stress on "GSM Modem". As in the ServersCheck's software, quite a few other players offer SMS capabilities through gateways. ServersCheck uses ClickATell to date as one SMS alerting option. If you use SMS alerting through a gateway, the same critic as for email alerting applies: you will not get any SMS message if your network is down.

GSM modems are modems that are attached to a host computer (in our case the system running our software). They require a SIM card and behave like a cell phone. This means that through these GSM modems the software will send out the text message using the wireless phone network to deliver the text message. Even when your network is down you will get the alert message.

We want to stress on the importance of GSM modems as being one of the best ways of alerting (next to email - one does not replace the other). To emphasise this importance, we have decided to run this month a promotion whereby you get in North America & Europe a free FALCOM SAMBA USB GSM Modem for the purchase with a software license from ServersCheck (Business 500 or Premium Edition).

Impact of temperature on systems

Customers have reported to us server racks having caught fire due to an airconditioning failure resulting in an overheat in the racks.

Fire is not something we hear quite often as a result of temperature increase and the lack of temperature monitoring. Fortunately most servers nowadays have built-in security shutting down equipment when temperature is too high.

One of the issues people least are familiar with, is the effect of too high temperatures on CPU calculations. I am not talking in this article about processors melting down - yes that happens more than you think and way before systems catch fire.

Let's return to calculation errors.

A CPU is made of transitors and when those are becoming hot then they tend to leak current. This leakage causes calculation errors having impact on applications stability. Too many errors can cause a system crash.

The frustrating part of this is that initially errors go unnoticed. Only when applications start to fail, server and network monitoring software deployed will trigger alerts. If you want to act before it is too late, then temperature monitoring should be part of your overall monitoring strategy as it has a direct impact on applications & systems availability.

Maximum operating temperature of a CPU is often set around 40°C (104 F). Going above that 40° operating temperature and you are risking big issues rather sooner than later.

Why monitor humidity in computer rooms?

Temperature sensors are our number one selling sensors. No doubt about that.

Last week we tried to explain the difference between ambient temperature monitoring and monitoring the temperature inside a rack, where your systems operate.

The fact that one is doing temperature monitoring is a big leap forward. Temperature is the threat we are most familiar with: entering a boiling server room when the airco unit went down - a familiar sight for many people.

A less visible threat to your equipment is humidity. Less visible also means more neglected; people omit to consider the danger of humidity related to their equipment.

There are 2 threats posed by humidity:
- ESD or Electrostatic buildup and discharge
- Corrosion

Everyone is familiar with corrosion: let metal stay in the rain and you will see it appears. With high humidity levels slowly your components could start showing signs of corrosion resulting in permanent loss of systems and potentially data too.

A low humidity level is a big contributor to the risks of ESD in a computer room, server room or data centre. Industry experts have determined that the risk of ESD increases the lower humidity is and the cooler the room is. Finding the right balance is tricky.

What are the recommended humidity ranges? Most strict ranges advocate humidity between 40% and 60%

Higher than 60% and corrosion may appear. Lower than 40%, ESD is your main ennemy.

Temperature monitoring in a server room

A question we often get from customers is: "how many sensors do I need?"

The actual question a customer needs to ask himself is: "how much do I want to spend on environmental monitoring?"

The basic monitoring is temperature. In later posts we will explain the benefits of other types of monitoring.

There are 2 main types of temperature monitoring:
- ambient temperature monitoring
- rack temperature monitoring

Ambient temperature monitoring is capturing the temperature in the room the same way you feel it when you are standing it. It is the temperature reading used by air conditioning units to operate.

However it is not the temperature in which your systems operate. In a number of server rooms we visited each time we could sense so called "hot zones". These are area's in the room where it is much hotter compared to others; often due to either layout of the room (cornered) or type of equipment (ie heavy server concentration in one area).

The problem with ambient temperature is that it takes some time to increase above a treshold when an issue arises in one particular area. If you are sitting in front of a fire place, it will be way warmer than in the rest of the room; especially when the room is larger. Same applies here.

In order to detect issues faster, one solution is to put every 3-5 meter or 10-15 ft a temperature sensor.

Best practice however is to monitor each rack individually with one sensor per rack. Using our IP based sensors, the sensors are positioned at the rear of the rack and near the top. Remember your physics class in high-school: hot air climbs.

The more sensors you deploy the earlier you will detect an issue.

However just one sensor in a room is far better than doing nothing.