Monitoring and controlling TSM client sessions


In Tivoli Storage Manager terms SESSION refers a connection between a TSM client and TSM Server, it can also be between TSM Storage Agent OR another TSM Server and TSM Server. Each client session is assigned a unique session number. To find the sessions connected to TSM server run the following command. 

Query Session

To know the details about a particular session, run the following command

Query Session <sessionnumner> format=detail

Also ReadHow to configure TSM Client Backup & Archive Schedules ?

You can determine the state of the server by examining the session state and wait time to determine how long (in seconds, minutes, or hours) the session has been in the current state.


TSM Server Session States

The server session state can be Start, Run, End, RecvW, SendW, MediaW, or IdleW. See the following definitions for the server session states

Start                        
Connecting with a client session.

Run                          
Executing a client request.

End                          
Ending a client session.

RecvW                
Waiting to receive an expected message from the client while a database transaction is in progress. A session in this state is subject to the COMMTIMEOUT limit.

SendW                   
Waiting for acknowledgment that the client has received a message sent by the server.

MediaW              
Waiting for removable media to become available. Aggregation can cause multiple media waits within a transaction and is indicated by one client message. If QUERY SESSION FORMAT=DETAILED is specified, the Media Access Status field displays the type of media wait state.

IdleW
Waiting for communication from the client, and a database transaction is NOT in progress. A session in this state is subject to the limit as specified in the server options file. If a client does not initiate communication within the specified time limit set by the IDLETIMEOUT option in the server options file, then the server cancels the client session. For example, if the IDLETIMEOUT option is set to 30 minutes, and a user does not initiate any operations within those 30 minutes, then the server cancels the client session. The client session is automatically reconnected to the server when it starts to send data again.


Cancelling the Sessions 

You can cancel a client session with the CANCEL SESSION command and the associated session number. Cancelling sessions may be necessary when a user's computer is not responding or as a prerequisite to halting the server. Administrators can display a session number with the QUERY SESSION command. Users and administrators whose sessions have been cancelled must reissue their last command to access the server again.

Also ReadHow to configure TSM Server Administrative Schedules ?

If an operation, such as a backup or an archive process, is interrupted when you cancel the session, the server rolls back the results of the current transaction. That is, any changes made by the operation that are not yet committed to the database are undone. If necessary, the cancellation process may be delayed.

cancel session 6

Monitoring and Controlling TSM Client Sessions

You can configure the TSM Server options parameters for automatically cancel long waiting or idle client sessions. The following server options must be appropriately configured to do this.

COMMTIMEOUT
Specifies how many seconds the server waits for an expected client message during a transaction that causes a database update. If the length of time exceeds this time-out, the server rolls back the transaction that was in progress and ends the client session. The amount of time it takes for a client to respond depends on the speed and processor load for the client and the network load. You can update this server option without stopping and restarting the server by using the SETOPT command. default value is 60 (seconds)

Example: Setopt commtimeout 100

IDLETIMEOUT
Specifies how many minutes the server waits for a client to initiate communication. If the client does not initiate communication with the server within the time specified, the server ends the client session. For example, the server prompts the client for a scheduled backup operation but the client node is not started. Another example can be that the client  program is idle while waiting for the user to choose an action to perform (for example, backup archive, restore, or retrieve files). If a user starts the client session and does not choose an action to perform, the session will time out. The client program automatically reconnects to the server when the user chooses an action that requires server processing. A large number of idle sessions can inadvertently prevent other users from connecting to the server. You can update this server option without stopping and restarting the server by using the SETOPT command. default value is 15 (minutes).

Example: Setopt idletimeout 30

Also Read: TSM Server Performance Tuning Parameters

THROUGHPUTDATATHRESHOLD
Specifies a throughput threshold, in kilobytes per second, a client session must achieve to prevent being cancelled after the time threshold is reached. Throughput is computed by adding send and receive byte counts and dividing by the length of the session. The length does not include time spent waiting for media mounts and starts at the time a client sends data to the server for storage. This option is used in conjunction with the THROUGHPUTTIMETHRESHOLD server option. You can update this server option without stopping and restarting the server by using the SETOPT command. default value is 0 (kb/sec).

Example: Setopt Throughputdatathreshold 50

THROUGHPUTTIMETHRESHOLD
Specifies the time threshold, in minutes, for a session after which it may be canceled for low throughput. The server ends a client session when it has been active for more minutes than specified and the data transfer rate is less than the amount specified in the THROUGHPUTDATATHRESHOLD server option. You can update this server option without stopping and restarting the server by using the SETOPT command. default value is 0 minutes.

Example: Setopt throughputtimethreshold 90




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