IBM Support

SQL2025N: An I/O error "-50" occurred on media "TSM".

Question & Answer


Question

If you are using Tivoli Storage Manager (TSM) and you receive error SQL2025N, return code -50, when attempting a restore or a backup in DB2® UDB, you may be facing a TCP/IP problem.

Cause

-50 is a TSM error meaning there is a TCP/IP problem.

In many cases, the reason is a timeout issue due to a low setting for the parameter COMMTIMEOUT in the TSM configuration that is causing TSM to terminate the connection.

For example, while DB2 UDB restore is recreating DMS containers, the TSM sessions are left idle and they can time out based on the value of the COMMTIMEOUT parameter that is set on TSM server. If DB2 UDB does not respond by that time, TSM disconnects the application and when DB2 UDB responds it recieves -50 from TSM because there is no connection.

Answer

Try one or more of the following:

  • Increase the COMMTIMEOUT and IDLETIMEOUT parameters located in the dsmserv.opt file on the TSM server or dsm.sys . Check the TSM documentation for the location of these files.
  • Change the COMMTIMEOUT to a very large number like 5 hours (18000). Increase IDLETIMEOUT as well. For help on finding the appropiate settings, please contact TSM Technical Support Team.

  • Make sure that TSM_MGMTCLASS and TSM_OWNER on the target instance is set to NULL.
  • If you have a firewall, make sure the firewall settings are not causing the problem.
  • Make sure TSM parameters are not too low. Increase the following parameters in the dsm.sys and dsmserv.opt files:
    • TCPWindowsize
      TCPBuffsize

    Increasing these parameters may reduce the possibility of a data sending issue. For example, the TCPWindowsize parameter specifies the amount of receive data in Kilobytes that can be in-transit at one time on a TCP/IP connection. The sending host cannot send more data until an acknowledgement and TCP receive window update are received. If the value for this parameter is too low, the sending host may need to send various packages of this size to complete all the data it needs to send. It can not send the next package until it has received an acknowledgement and TCP receive window update. Sending information in various packages has some risks, for example, a package can get lost causing the data to be corrupted, or there may be a network issue in the middle of sending the packages causing the connection to drop.

    Please contact the IBM TSM technical support team for more detailed assistance on how to increase these parameters.

  • Make sure you have PASSWORDACCESS in dsm.sys file set to PROMPT.

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Document Information

Modified date:
16 June 2018

UID

swg21208412