Diagnose Network Database Damage

Abstract

In a network environment, intermittent failures of the network can cause damage to the Capable 21C database.  This can be difficult to diagnose if the network only fails for short periods of time.  This knowledgebase article describes how to perform some of this diagnosis.

Underlying challenge

Networks are not nearly so robust as many people might think. It is quite common for a network to lose connectivity for short periods of time (eg a few seconds).  However, this loss of connectivity can cause severe damage to the Capable 21C database.  Refer to the resolution section (below) for some diagnostic steps to undertake.  This knowledgebase article does not describe techniques to resolve all network issues, but does cross reference some other knowlegebase articles that may help.

This knowledgebase article is intended for PC Technicians or operators who are more fluent with the Microsoft tools for network management.  Note that none of these tests involve the use of Capable 21C.  These tests can all be performed without Capable 21C installed on the workstation.

Resolution

Refer to the following KBAs
  KB-Compact and Repair Database.asp
  KB-Installing Capable 21C in a network.asp
  KB-RTE 52 Bad File Name or Number.asp
  KB-Improve Performance in a network.asp
  KB-Windows XCACLs.asp 

Check that the network is operational at all:

1. Go to the main PC (or server).
2. Identify the main PC's (or server's) IP Address and name.
3. Go to a workstation PC.
4. Click Start|Run.
5. Key \\XXXXXX and press ENTER. Substitute the server name for XXXXXX.
6. If this fails, it is likely that the server name was not recorded correctly in step 2.
7. Click Start|Run again.
8. Key \\X.X.X.X and press ENTER.  Substitute the IP Address of the server for X.X.X.X
9. If this fails, the network is inoperable.  Check routers/switches and network configuration on the workstation.  If this test fails on multiple workstations, check the network configuration on the server.

Check that the network share is operational:

1. Go to the main PC (or server).
2. Open a My Computer window and drill into C:\
3. Right click on the Capable folder, and check the sharing settings.
4. Ensure that the share allows changes, and note the share name.
5. Go to a workstation PC.
6. Click Start|Run.
7. Key \\XXXX\yyyy and press ENTER  Substitute the server name for XXXX and the share name for yyyy.
8. If this test fails, check the share name, and security settings in the network.

Check that the network share is configured correctly:

1. After performing a successful test that the network share is operational (above):
2. Stay at the workstation PC.
3. Try to create a new folder in the shared Capable folder (eg Right click and choose New|Folder).
4. If this test fails, it is likely that the share is not configured to allow changes.  Check the share settings on the server.
5. If the share settings on the server are correct, it is likely that the XCACLs on the server have become damaged.  Refer to KB-Windows XCACLs.asp
6. If the test is successful, remember to remove the newly created folder.

Try to alter the Capable.MDB file from a workstation:

1. After performing a successful test that the share is configured correctly (above):
2. Stay at the workstation PC.
3. If MS Access is installed on the PC, try to open the Capable.MDB file using Microsoft Access.  MS Access may report that it cannot change database objects, but should not report that the file is 'Read Only'.  If MS Access reports that the database file is damaged, needs to be repaired or is not a database file, refer to KB-Compact and Repair Database.asp and repeat this test.
4. If MS Access is not installed, alter the Capable.MDB file by renaming it.  If this succeeds, remember to rename it back to Capable.MDB.
5. If step 3 or 4 fail, this suggests that the XCACLs on the server have become damaged.  Refer to KB-Windows XCACLs.asp

Detailed Information

It is possible to diagnose some common causes of network failure:

1. Open the Event Viewer on the server PC.
2. Browse the System log for TCPIP events.  In particular, look for event number 4202.  This indicates network failure.
3. Open the Event Viewer on each workstation in turn looking for the same event.
4. If the event occurs on one PC only, it is likely to be either a NIC failure, a cable fault or a driver issue for the NIC.
5. If the event occurs on multiple PCs, it may also indicate a router/switch failure.  Check the firmware on the router/switch or replace the unit.

Other suggestions in ascending order of cost:

• Re-install the drivers for the NICs in each PC.  Check for updated drivers for the NICs.
• If one PC is almost always off, try swapping it with another PC in the network.  If this significantly reduces the frequency of database damage, examine both swapped PCs closely for faulty/failing network hardware.
• Try swapping network cables.
• Replace the router/switch.
• Replace the NICs in each PC.
• Re-install Windows on each PC (whilst this carries no physical cost, it takes a lot of time).

Copyright 2008 Capable Software Pty Ltd

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