Uptime
Uptime Uptime is the period of time when a site performs well.

Uptime corresponds to the time when a site is accessible from the Internet. The opposite term - downtime - shows for how long a site has not been working during specified period of time. Usually uptime is measured in percents, and for period of time is choosen year. Percents over the year could be easily transformed into time values. Some typical values of uptime and corresponding period of unavailability during the year are shown here:

90% - 876 hours

99% - 87 hours, 36 minutes

99.9% - 8 hours, 45 minutes, 36 seconds

99.99% - 52 minutes, 34 seconds

So high uptime is really important. Even if it seems that 99% is pretty high value - it corresponds to several days of failure. If that happens in a row, many clients can be lost. Uptime value is usually guaranteed by web hosting, where the site is hosted. Website Monitoring may help you to increase the uptime and check if the value, declared by the hosting company, is real.

  • CM.Glossary.WebsiteMonitoring
  • CM.Glossary.Downtime
  • CM.Glossary.WebHosting
  • CM.Glossary.Availability
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Very usefull service, helps us to monitor activity of our sites.

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- A.
Database Monitoring with HostTracker

We’re happy to introduce our newest monitoring feature - Database Check – that is easy to use, crystal-clear to understand and designed to get you through your website ‘critical hours’ as smoothly as possible.

We’re happy to introduce our newest monitoring feature - Database Check – that is easy to use, crystal-clear to understand and designed to get you through your website ‘critical hours’ as smoothly as possible.

There is a wealth of different collector services for gathering and analyzing performance information from, for example, the number of visitors, disk usage to the duration of a database session and geographical distribution of the audience that visits the website. In the real world, it is very common to find two or more of these metrics presented together. Anyway, the problem is that you should not only assess these numbers but also somehow examine and compare them.

All that made HostTracker team eventually develop a Database Check – a perfect tool for deep database monitoring and successful troubleshooting database performance problems.

Task Configuration Concepts

Generally speaking, adding a new Database Check won't take long to set up. Once it is enabled, you’ll get the chance to adjust the check to suit your overall strategy. Now let’s look at some of the available options to better understand how they can be effectively applied.

First and foremost, this feature has an option to include a specific database query every time you run the check, whilst still having the opportunity to manage the processing data. If you don’t want to specify any query – the service will verify the ability to connect to the database. In addition, the Database Check tool supports a deferred execution option, which allows you to specify the point of query declaration and track its results.

Besides that, you can use any command - from a simple Select statement to a more complex procedure, - as a database query. However, the specified request should be executed in 30 seconds or less, otherwise, the error message will be generated. Basically, you’ll get the 408 Request Timeout or related error.

Please note: When enabling a new DB monitoring check, there are a couple of things to consider. Use an SQL statement that returns a single value. Furthermore, this value should be returned in the first column of the first row. This step is vital for further performance analysis of the monitored system.  

At the same time, in case of using a DML command as a statement, you’ll also get the total number of rows being affected.

The following example shows the graphical interpretation of the results from executing DELETE statement, according to the specified condition:

For the record, the collected results are not only displayed in a real-time graph, but also stored for later analysis. Besides, such a solution can really help to get valuable insights into how to optimize your database performance.

Moreover, at this stage, you can specify the type of selection criteria. You can choose from no, equal/not equal, greater/less than, in/out of range.

Once the system finds some deviation in records from the expected results - you will receive a notification. To boot, you can control which events you want to receive alerts for and which ways (Skype, Viber, Telegram, Slack etc.).

First Steps In Starting Successful Performance Troubleshooting

This example shows how to create a check for both tracking the growth of all the database log and data files and getting alerts when critical database size is reached. It implies, the following example contains information about the file data/log file size, the total space used, free space details etc. So what you need to do:

  1. Create a new query that displays how much free space you have in your tablespace.

          SELECT
          convert(DECIMAL(12,2),round(sysfile.size/128.000,2)) AS 'FileSize/mb'
          , convert(DECIMAL(12,2),round(fileproperty(sysfile.name,'SpaceUsed')/128.000,2))
          AS 'Used/mb'
          , convert(DECIMAL(12,2),round((sysfile.size-fileproperty(sysfile.name,'SpaceUsed'))/128.000,2))
          AS 'Free/mb'
          , filegroup.groupname AS 'File-group'
          , sysfile.[name],sysfile.[filename]
          FROM dbo.sysfiles sysfile (NOLOCK)
          inner join dbo.sysfilegroups filegroup (NOLOCK) ON filegroup.groupid =
          sysfile.groupid
          UNION ALL 
          SELECT
          convert(DECIMAL(12,2),round(sysfile.size/128.000,2)) AS 'FileSize/mb'
          , convert(DECIMAL(12,2),round(fileproperty(sysfile.name,'SpaceUsed')/128.000,2))
          AS 'Used/mb'
          , convert(DECIMAL(12,2),round((sysfile.size-fileproperty(sysfile.name,'SpaceUsed'))/128.000,2))
         AS 'Free/mb'
         , (CASE WHEN sysfile.groupid = 0 THEN 'Log' END) AS 'File-group'
         , sysfile.[name],sysfile.[filename]
         FROM dbo.sysfiles sysfile (NOLOCK) WHERE groupid = 0
         ORDER BY [File-group],sysfile.[name]         

      2.  After execution, you should get the following results:

     3.  Add a condition of selection:

  • Query result - select "value in the first column of the first row (mainly for SELECT)".
  • Result verification - choose "less than" and add "1000"  as the max value.

Finally, you’ll get the following result once all the previous stages have been successfully completed: if the log file size exceeds 1 GB, you’ll receive a notification.

Please keep in mind all data collection history information is saved and always available to view. It means you can easily identify the cause of this or that problems, for instance, the reason for rapid tablespace growth.

Adding a New Database Monitoring Task

To activate a new Database Check you need:

      1.  Fill in the following fields:

  • Server – enter your server name;

  • Port -  add your port number;

  • Database – add your database name;

  • User ID- enter the login name under which the check should be executed;

  • Password – add the password that corresponds to your login.

For this task only, it is recommended to create a new user account with limited rights.

       2.  Provide access to your database. For this, add the IP addresses of the HostTracker agents to a Firewall Whitelist and your server list.

Note that, the IP addresses of our agents are permanent.

       3.  When ready, click on Save.

If you have any questions about this feature, well, just send us a message. We’re always ready to help!

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Home > Blog > HostTracker_under_Azure

Those, who actively involved with the Web, should know HostTracker, a company from Ukraine, which has been supporting one of the leading global web monitoring services since 2004. Its goal is to monitor site health and accessibility in near-real-time access. Using alert message system, HostTracker allows to reduce downtimes, to improve quality of service for users, to quickly localize troubles...

​Those, who actively involved with the Web, should know HostTracker, a company from Ukraine, which has been supporting one of the leading global web monitoring services since 2004. Its goal is to monitor site health and accessibility in near-real-time access. Using alert message system, HostTracker allows to reduce downtimes, to improve quality of service for users, to quickly localize troubles, and etc.

Architecturally, HostTracker includes a server-based hub, acting both as a data collector and control center, and a series of software agents, launched in various regions – typically using the equipment operated by major providers, hosters and affiliates. The geographically distributed architecture provides common system reliability and also allows collecting data in terms of access speed, bandwidth and other key performance characteristics on regional level – a critically important feature for the international business.

The first version of HostTracker, which is still functioning and providing services for tens of thousands of customers, was Linux based. Today, it is supported by nine control servers, located and organized in two DPCs on collocation principle, and few dozens of agents. Considering that the final objective of web monitoring is focused on increasing the uptime of client-based web resources – whereas 95% of HostTracker customers were able to increase it up to 99% – then, performance and accessibility of the service itself are not just critical, but rather fundamental parameters that influence the whole business. Theoretically, HostTracker should demonstrate accessibility close to 100%. However, an extensive growth of the service made this task hard to solve.

HostTracker was facing constantly increasing network traffic – a problem for seamless operation of the service. Inability to add new control servers on-the-fly, difficulties when maintaining not uniform and multiple-aged hardware was another limiting factor. Moreover, the desire to develop the service through wider protocol and network service support was meeting certain obstacles. “Unfortunately, for Linux there was a limited choice of ready-to-use solutions and libraries, while inventing something completely new was difficult”, says Artem Prisyazhnyuk, HostTracker director. “We had an idea of reviewing the stack of technologies we used for a more sophisticated one and after taking a closer look at the .NET platform, its potential in terms of scalability and network support, I realized that was exactly the thing we had been looking for.”

It was sure that migrating to a completely different platform should be a complex task – the project extended over three years. However, it was like blessing in disguise: during this period, the world has seen the cloud computing that seemed an ideal tool for solving both the scalability problem and putting aside one’s own whole infrastructure. Besides, the PaaS model allowed to remove most of the effort in terms of administering the solution and to control the application as a self-contained entity, to the extent of complete automation, and thus, Windows Azure had in fact no alternatives.

As a result, the second version of HostTracker, commercial operation of which started in May 2012, is already functioning under Windows Azure. Its central ingredient is realized as Web Role and associated with SQL Azure Database – it provides external portal, analytics and report generation, control of monitoring applications. The latter are ensured with instances of Worker Role, which also use SQL Azure Database to store their data and to provide the service scalability depending on the network loading. Agents are functioning as they did before, with the viability of their transfer to Windows Azure being considered.
Now, HostTracker uses HTTP/HTTPS and ICMP protocols to monitor specific ports, including various methods (HEAD/POST/GET), and etc.
 

HostTracker instant check



Alarm reporting is available via email, SMS and instant messages. The customer can receive reports with statistics about resources being controlled and their performances. You can spend only 6 minutes to make monitoring settings for five sites, while the average response time in case of failure is limited by a couple of minutes, and it takes 1-3 minutes more to inform the customer about the problem. Using this service, anyone can check any site, including access from various regions.

 As a result, if on the one side the transfer to the .NET platform itself gave us the potential to modernize HostTracker, to optimize the application architecture and realize new internal functions, then, on the other side, the migration to the cloud allowed to refuse from less important, though time consuming activities such as administering the solution, and, first of all, to reach necessary performance indicators. Microsoft, for all basic Windows Azure services, declares 99,9% accessibility and guarantees monthly refunds, should this indicator be lower. This creates a firm ground for operating such services like HostTracker, as the accessibility is the most critical parameter for these applications. Using the cloud infrastructure also provides a better protection for the service: unauthorized access to the application and many types of attacks are effectively excluded, while the data safety is ensured by triple reservation.

HostTracker received another advantage from abandoning its own infrastructure. The service’s performance characteristics are also rather critical, for they directly affect the failure reporting system operation. In this respect, Windows Azure is virtually a drainless source of computing power. This means that by timely starting additional monitoring instances you can support HostTracker functioning parameters on the necessary level. Moreover, the cloud environment is exactly what you need in order to make this process almost fully automatic, excluding further need for direct control.

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