Document revision date: 30 March 2001
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DECamds User's Guide

Previous Contents Index Setting Window Customizations

The Sort, Filter, and collection interval settings at the data window level affect performance. Follow these guidelines to balance customization with performance:

5.5.2 Optimizing System Settings

Changing several system settings might improve the performance of DECamds on your system. The following sections discuss these settings and how to change them. Setting Data Link Read Operations

Increase read operations to the data link by changing the logical name AMDS$COMM_READS in the AMDS$CONFIG:AMDS$LOGICALS.COM command procedure. The AMDS$COMM_READS logical name controls the number of requests for data (read operations) queued to the data link.

If you increase data collection, increase the number of requests that can be queued. Compaq recommends two requests for each node being monitored. Each read operation queued requires 1500 bytes of BYTLM quota. Setting the Communications Buffer

Increase the communications buffer by changing the logical name AMDS$COMM_BUFFER_SIZE in the AMDS$CONFIG:AMDS$LOGICALS.COM command procedure. The buffer controls the size of the global section used for communication between the provider node and the communications process.

When DECamds cannot keep up, it displays the following warning message:

AMDS$_COMMBUFOVF---communications buffer overflow.  Increase the buffer by 25 percent. 

In addition to increasing the value of the AMDS$COMM_BUFFER_SIZE logical name, set the system parameter GBLPAGFIL on the provider node to cover the increase. This adds to the amount of data collection that DECamds can perform.

The value of the GBLPAGFIL system parameter must always be higher than the number of FREE_GBLPAGES. To determine the value of FREE_GBLPAGES, enter the following commands:


The value of A must conform to the following formula:

2 * ( (buffer_size / 512) + 512) 

5.5.3 Optimizing Performance with Hardware

Table 5-7 provides an approximate guideline for the number of nodes you can monitor when running DECamds on certain computer types.

Table 5-7 Monitoring Nodes
Monitoring Computer Type Number of Nodes Monitored
  Observation Only Observe and Fix
VAXstation 3100 0-30 0-20
VAXstation 4000 Model 60 20-60 20-50
VAX 6000 1 75-150 65-130
VAX 4000 Model 90 75-150 65-130
DEC 3000 Model 400 0-50 0-50
DEC 4000 Model 620 0-70 0-70
DEC 7000 Model 720 Any number Any number

1With DECwindows display directed to a workstation

Follow these suggestions when choosing and configuring a console:

Appendix A
Installing the DECamds Data Analyzer

This appendix explains how to install the DECamds Data Analyzer software on OpenVMS Alpha and OpenVMS VAX Version 6.2 and later systems.

Beginning with OpenVMS Version 7.2, the Data Provider ships as part of the OpenVMS installation. Installing or upgrading to OpenVMS Version 7.2 or later automatically installs the Data Provider on your system. You can run the Data Provider on any VAX or Alpha Version 6.2 or later system.


The Compaq Availability Manager web site might refer you to a more recent version of the Data Provider than the one on the current OpenVMS VAX or Alpha operating system CD-ROM. Compaq recommends that you install the DECamds Data Provider software using the version indicated at the following URL: 

Section A.7 explains how to start using the Data Provider.

This chapter contains the following sections:

A.1 General Installation Information

DECamds provides online release notes. Compaq strongly recommends that you read the release notes before proceeding with the installation. You can print the text file of the release notes from the following location:


DECamds consists of client and server software:

In earlier versions of OpenVMS, you needed to install both both the Data Analyzer and Data Provider software on your system from the latest DECamds kit. Beginning with OpenVMS Version 7.2, you need to install only the Data Analyzer software on the system where you run the client, or graphical user interface. You need to do this to obtain the new library for DECamds Version 7.2 and later.

A.2 Data Analyzer Installation Requirements

This section provides a checklist of hardware and software requirements for installing the DECamds Data Analyzer. A typical installation takes approximately 5 to 10 minutes per node, depending on your type of media and system configuration.

A.3 Obtaining the Data Analyzer Software

The Data Analyzer software is available on the OpenVMS operating system layered product CD-ROM or from the Compaq Availability Manager web site.

Follow these steps to download the software from the web:

  1. From the Availability Manager home page, click Software Download. The Availability Manager home page is at the following URL: 

  2. Complete the user survey, which allows you to proceed to the Download web page.
  3. Click one or both of the DECamds executables:

        DECamds - Alpha: decamds0721b.pcsi-dcx_axpexe 
        DECamds - VAX:   decamds0721b.pcsi-dcx_vaxexe 

  4. Save the executable to a device and directory of your choice.
  5. Run the executable and accept the default file name. The result will be:

        DECamds:               DEC-VMS-AMDSV0702-1B-1.PCSI 

The next section provides installation instructions for the Data Analyzer.

A.4 Installing Data Analyzer Software from a PCSI Kit

This section describes the installation procedure on an OpenVMS Version 6.2 or later systems from a POLYCENTER Software Installation (PCSI) kit.

Sample Installation on an OpenVMS Alpha System

Example A-1 shows a sample installation on an OpenVMS Alpha system. This sample was run on a system that had no previous version of DECamds installed. Depending on which layered products you have on your system, you might see additional messages and questions when you perform your installation.

Example A-1 Sample OpenVMS Alpha Installation

$ product install amds 
The following product has been selected: 
DEC VMS AMDS V7.2-1B                   Layered Product 
Do you want to continue? [YES] 
Configuration phase starting ... 
You will be asked to choose options, if any, for each selected product and 
for any products that may be installed to satisfy software dependency 
DEC VMS AMDS V7.2-1B: DECamds (Availability Manager for Distributed 
Systems) V7.2-1B 
COPYRIGHT © © 1994, 1995, 1999 -- All rights reserved 
Compaq Computer Corporation 
License and Product Authorization Key (PAK) Information 
Do you want the defaults for all options? [YES] 
DECamds Data Provider Installation Verification Procedure 
DECamds Startup File 
DECamds Logicals Customization File 
DECamds Data Provider Security Access File 
DECamds Data Analyzer Security Access File 
DECamds Data Analyzer Installation Verification Procedure (IVP) 
IVP may fail due to the following PQL values being too low: 
See the file AMDS$SYSTEM:AMDS$PCSI_IVP_OUTPUT.LOG for help on failure. 
Do you want to review the options? [NO] 
Execution phase starting ... 
The following product will be installed to destination: 
DEC VMS AMDS V7.2-1B                   DISK$ALPHA_V72:[VMS$COMMON.] 
Portion done: 0%...20%...30%...40%...50%...60%...70%...80%...90%...100% 
The following product has been installed: 
DEC VMS AMDS V7.2-1B                   Layered Product 
%PCSI-I-IVPEXECUTE, executing test procedure for DEC VMS AMDS V7.2-1B ... 
%PCSI-I-IVPSUCCESS, test procedure completed successfully 
DEC VMS AMDS V7.2-1B: DECamds (Availability Manager for Distributed 
Systems) V7.2-1B 
This product requires the following SYSGEN parameters: 
GBLPAGES add 1172 

A.5 Postinstallation Tasks on Data Provider Nodes

Perform the following tasks after installing DECamds on Data Provider nodes:

  1. If you have not read the release notes, please read them.
  2. Modify user accounts.
    Users who maintain the security or group name files or load new versions of the driver need privileges associated with the driver startup procedure.
  3. Add AMDS$STARTUP.COM to the node's startup and shutdown procedures to provide for automatic startup and shutdown of the Data Provider driver when a node is booted or shut down.
    Add the following command line to SYS$MANAGER:SYSTARTUP_VMS.COM:


    Also, edit SYSHUTDWN.COM to add the following line:


  4. Modify default security files.
    To implement fixes, which require write access, the security files must bemodified. The Data Provider security file contains a list of three-part codes representing Data Analyzer nodes that have read or write access to that node.Refer to Section 1.3 for complete instructions about designing security files.
  5. Assign a node to a group.
    See Section
  6. Start DECamds (the Data Provider).
    Even though the IVP starts and stops the driver, you must start the Data Provider drivers by entering the following command on each node:



    Starting, stopping, or reloading DECamds (the AMDS$STARTUP.COM procedure) requires at least TMPMBX, NETMBX, SYSNAM, LOG_IO, and CMKRNL privileges. Use the OpenVMS Authorize utility (AUTHORIZE) to determine whether users have the required privileges and then make adjustments as needed.

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