Citrix states in their article: CTX108553

Document ID: CTX108553, Created on: Jan 3, 2006, Updated: Apr 26, 2006

Products: Citrix Presentation Server 4.0 for Microsoft Windows 2000, Citrix Presentation Server 4.0 for Microsoft Windows 2003, Citrix MetaFrame XP 1.0 for Microsoft Windows 2000, Citrix MetaFrame XP 1.0 for Microsoft Windows 2003, Citrix MetaFrame Presentation Server 3.0 for Microsoft Windows 2000, Citrix MetaFrame Presentation Server 3.0 for Microsoft Windows 2003

Environment

• Citrix Presentation Server 4.0

• Windows 2000 or Windows 2003

Symptoms

When a user attempts to connection to a Citrix Presentation Server they receive the below error message:

“Cannot connect to the Citrix MetaFrame server. The Citrix MetaFrame server is not available, please try again later.”

Additional symptoms may include:

1. The following error in the server’s system event log:

Source: SRV
Type: Error
Event ID: 2020
Description:
The server was unable to allocate from the system paged pool because the pool was empty.

2. Users may receive the following error message when trying to log on through an ICA or RDP session:

“Windows cannot log you on because the profile cannot be loaded. Contact your network administrator

DETAIL – Insufficient system resources exist to complete the requested service.”

This error can be caused for a variety of reasons; the best way to identify whether the problem is the exact issue described by this document is to perform a CDF trace on the MF_Driver_Wdica module.

You will need to perform the below steps in order to use CDF tracing to identify this issue:

1. Start CDF trace on MF_Driver_Wdica.

2. Attempt to connect to the problem server through ICA, confirm that the error above occurs.

3. Stop the CDF trace.

4. Open and analyze the CDF trace, if the below trace message is found, the problem is the same problem described in this document:

wdica ChangeOutputSystemToReducer: Couldnt allocate 393744 bytes - status c0000017

Cause

This is due to a failure of Wdica.sys, the driver responsible for communication between a Citrix Presentation Server and an ICA client, when it attempts to allocate memory for the buffers used in compression.

Starting with the release of Citrix Presentation Server 4.0, Wdica.sys allocates from the system’s paged pool. This has shown to increase single server scalability, and in most cases it will, as Wdica.sys was previously allocating from an area known as the non-paged pool, which has a smaller maximum size than the paged pool. The maximum size of each pool is shown in the table below.

Operating System

Maximum Non-Paged Pool Size

Maximum

Paged

Pool Size

Windows 2000

256 MB

491.875 MB

Windows 2003

256 MB

650 MB

Windows 2003 64-bit

128 GB

128 GB

Resolution

There are two possible causes for this problem:

• An improperly sized maximum paged pool

• A memory leak or other high paged pool memory consumption by a problematic application

In many cases, the reason a machine runs out of paged pool memory is that the system is not configured to use the maximum available paged pool size. The maximum paged pool size is calculated at boot and cannot be recalculated without rebooting the system. This problem occurs more frequently on a Windows 2000 Terminal server because Windows 2000 holds every loaded registry hive (including user profile hives) in paged pool memory. This means that with each additional user who logs on to the Windows 2000 Terminal server, the available paged pool memory is decreased not only by the amount used by the launched application, but also by the size of the user’s profile registry hives. In Windows 2003 the Configuration Manager (registry) does not use paged pool to load the user profiles, but instead only consumes memory for the hives being used at any one time.

See the below Microsoft article to maximize the available paged pool memory:

Server is unable to allocate memory from the system paged pool

It is important to note that by maximizing paged pool memory, you are decreasing the amount of another resource, system PTEs, so it is better to take a more scientific approach to setting the size of the system’s paged pool memory. The below Microsoft document explains this in detail:

How to Configure the Paged Address Pool and System Page Table Entry Memory Areas

Note that the Microsoft document above references attaching a kernel debugger to the machine. You can bypass this step by substituting the LiveKd utility from Sysinternals. You can run this utility live on the server console without modifying or hooking a kernel debugger to the target computer’s serial port and halting normal operation of the server. You need to launch a new instance of LiveKd each time you want to see an updated snap shot of kernel memory usage.

It is also important that the possibility of a problematic application consuming memory without ever releasing it properly (memory leak) is ruled out.

You can use poolmon.exe to view current paged pool consumption:

How to Use Memory Pool Monitor (Poolmon.exe) to Troubleshoot Kernel Mode Memory Leaks

To identify which component is consuming memory reference the following Microsoft document:

How to Find Pool Tags That Are Used By Third-Party Drivers

More Information:

For information on how to collect a CDF trace, see:

CTX104578 - Using Citrix Diagnostic Facility and the Access Suite Console for Tracing

CTX108380 - How to Make a Real Time CDF Trace Using the CDF Viewer (CdfView.exe)

For information on how to analyze a CDF trace, see:

CTX106233 - Common Diagnostics Facility Viewer (CDF Viewer)

For information on how to use Sysinternals’ LiveKd utility:

Sysinternals' LiveKd

You may also see the above error on MetaFrame XP if you applied the following hotfixes:

• Hotfix XE104R01W2K010 - For MetaFrame XP 1.0 for Windows 2000 Server

• Hotfix XE104R01W2K3012 - For MetaFrame XP 1.0 for Windows Server 2003

And has been corrected with the below hotfixes:

• Hotfix XE104R02W2K3011 - For MetaFrame XP 1.0 for Windows Server 2003

• Hotfix XE104R02W2K011 - For MetaFrame XP 1.0 for Windows 2000 Server

As well as MetaFrame Presentation Server 3.0 if you applied the following
hotfixes:

• Hotfix Rollup Pack MPSE300W2KR04 - For Metaframe Presentation Server 3.0 for Windows 2000 Server

• Hotfix Rollup Pack MPSE300W2K3R04 - For Metaframe Presentation Server 3.0 for Windows Server 2003

And has been corrected with the below hotfixes:

• Hotfix MPSE300R04W2K3030 - For Metaframe Presentation Server 3.0 for Windows Server 2003

• Hotfix MPSE300R04W2K026 - For Metaframe Presentation Server 3.0 for Windows 2000 Server