ITCAM4Tx - ISM agent capacity planning to monitor around 120 HTTP server URLs

Answer

Q1) Would any Windows Workstation be OK? if yes what specifications.

A1) Microsoft Windows OS needed and supported by ISM v7.3 agent for example :

Windows 2003 Server Standard, 32-bit and 64-bit

Windows 2003 Server Enterprise, 32-bit and 64-bit

Windows 2003 Server Web Edition

Note: Windows 2003 requires a hot fix to support IPv6 on the ICMP monitor. See Microsoft Support for further information.

Windows 2008 Enterprise Edition, 32-bit and 64-bit

Windows 2008 Server Standard, 32-bit and 64-bit

Windows 2008 Server Enterprise, 32-bit and 64-bit

Windows 2008 Server DataCenter, 32-bit and 64-bit

latest prerequisites for v7.4, see chapter "System requirements and prerequisites" :

Q2) is any Windows Virtual Server OK? if yes what specifications.

A2) yes, same Windows OS for Virtual Server as above

Q3) Assuming that each request would take around 10 seconds to get the response, and that 120 requests would be sent at a time, how much minimum memory is required ?

A3) That requirement doesn't seem too much to be handled by a single ISM agent. That's a pretty light load. So any machine capable of running a modern Windows installation should be able to cope with that number of elements. Certainly 2GB of memory and any modern CPU would be sufficient.

The only thing that could increase that requirement would be the size of the web pages. It the pages were unusually large, then ISM agent might require a bit more memory.

Remark:

One formula that can be useful to consider later , and that is documented in ITCAM 4 Tx V7.3 Installation Guide, is the "Poll Intervals"; see below info extracted from page 65 of 556 of this guide.

Table 11. Optimal settings for Internet service monitor properties

Property Description - Best setting

MaxCCA : Sets the maximum number of threads running concurrently. The ICMP monitor does not provide this property because it is single threaded.

50 for high-volume polling (more than 500 profile elements)

10 for low-volume polling

Pause : Sets the interval (in milliseconds) at which the monitor spawns threads.

Setting it to a higher value, such as 100 or more, causes the monitor to spawn threads more slowly.

50 for high-volume polling (more than 500 profile elements)

100 for low-volume polling

QSize : Set the maximum size of the monitor's event queue on disk.

10 MB for most situations. In larger environments, increase this value for each monitor by 1 MB per 1000 elements.

Poll intervals : The number of poll intervals affects the response times. A guideline is provided to help with choosing the appropriate interval.

You define the poll interval when you create profile elements. Use the following formula as a guide:

minimum poll interval = number of profile elements × average response time / MaxCCA

The number of profile elements configured for a monitor determines the total number of tests performed by the monitor. The average response time varies according to the monitoring environment, so when selecting the poll interval, choose a value appropriate to the application environment. In the worst case, if the application fails to respond then the average response time will be the

timeout value set for the monitored element.

Example:

Assuming that you would have several hundreds of elements in your ISM profiles, let's say 300,

minimum poll interval = number of profile elements × average response time / MaxCCA

minimum poll interval = 300 * 10 / 50

so !minimum! poll interval would be : 60 secs

it's also documented in V7.4 documentation :