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Author's profile photo Martin English

The SAP Availability Log

A basic metric for system-wide performance is up time, or system availability.  Generally, this is absolute time less scheduled outages. There are many manual and automatic ways of tracking this, but one of the simplest, yet most accurate, for an SAP system is the available.log.

available.log is stored in the work directory (/usr/sap/<sid>/work).  If you don’t have Operating System access, you can also view the file via transaction AL11.  Find and select Directory parameter DIR_INSTANCE, then drill down into this directory…</p>

Transaction AL11, DIR_INSTANCE

…find the work directory and drill down again,…

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… sort the resulting list of files, and availability.log should be at or near the top.</p>

It is written by the SAP service sapstartsrv.exe. The service checks the status of the actual process list (i.e. the entries you see in the MMC SnapIn under the “Process List” node).   If all processes are “green” the instance is considered to be available.  Since the status information of the Dispatcher is calculated from multiple parameters (process running + connected to message server + shared memory available + good dialog queue time) the information in available.log is very reliable.

The information is checked and updated every 60 sec and at instance startup and shutdown. The default threshold for a “good” dialog time is 5.0 sec. You can adjust this threshold with the profile parameter max_dia_queue_time in the default or start profile (service must be restarted after changing it).

If the service notices that the last update to ‘available.log’ is older than 60 secs (e.g. due to computer shutdown), it will always start a new line in ‘available.log’, for example you may see:

<p>Unavailable 30.04.2009 15:31:35 – 30.04.2009 21:28:47<br />

Unavailable 30.04.2009 21:52:32 – 02.05.2009 08:42:39

instead of

<p>Unavailable 30.04.2007 21:52:32 – 02.05.2007 08:42:39</p>

Because of the time delay required to cause this situation, it is extremely likely that at least one service related to the SAP instance was not running (e.g. caused by computer shutdown).

Currently, no SAP application (that I know of !!) reads available.log –  it’s just a simple log file to help measure your system availability.

Caveat: You do need to make sure that all the processes that you would see in the SAP MMC are running correctly for correct values to show in available.log.  While experimenting several years ago, I had a situation where the igswd.exe service was not running correctly.  I had modified the start profile, but restarted the system incorrectly.  Until I did this, which reloaded my profile changes correctly, available.log was reporting that the entire SAP system was unavailable.</p>

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      Author's profile photo Former Member
      Former Member
      can be found here
      Author's profile photo Martin English
      Martin English
      Blog Post Author
      Thanks Mike !! 
      Author's profile photo seventyros roshan
      seventyros roshan

      firewall team complained that sap WAS was not avaialble on a particular date for 15 minutes(10am to 10:15 am). Hence firewalls could not redirect to the logon page of SAP EP as the page is hosted on SAP WAS and firewall did not get any reponse from SAP WAS during the mentioned timeframe.

      Can available.log file help us find whether SAP WAS was avaialble/not availalble during the mentioned timeframe.

      thank you !


      SAP EP

      Author's profile photo Former Member
      Former Member

      Thanks for this entry.

      I wondered why one my systems reported to be "Unavailable" in this log file. And now, I know why.

      By the way, I wrote a simple script to read this file and get some stats. If anyone is interested you can find it here.