IBM Support

When the IBM Spectrum Protect servermon component is enabled, the gstack command can cause I/O operations to fail on tape devices

Flashes (Alerts)


IBM Spectrum Protect Version 8.1.7 and later includes a servermon component, which is used for continuous data collection. When the servermon component is enabled on the Linux® operating system and the Linux SCSI generic device driver (sg) starts to process an input/output (I/O) operation, the I/O operation can fail.


This issue occurs because the gstack command blocks an I/O operation on the tape device. When this block occurs, the ERESTARTSYS error is generated in the kernel of the ioctl() system call. After gstack command processing is completed, the I/O block is gone, and ioctl() reissues the call for the I/O process. As a result, the same SCSI command is run twice. The first run is successful, but the I/O return is blocked by the gstack command, and the second run fails. The IBM Spectrum Protect server receives only the results from the second run.
Versions Affected:
IBM Spectrum Protect V8.1.7.000 and later servers on the Linux operating system.
Problem Resolution:

This issue is outside the scope of the IBM Spectrum Protect server. 
The following workarounds are available:
1. If you do not have to run the servermon component, you can specify the alwaysonservermon off option in the server options file and then restart the server. The update takes effect after you restart the server.
  • The ALWAYSONSERVERMON option is on by default in V8.1.7.000 and V8.1.8.000.
  • To determine whether the option is enabled, you can issue the query opt alwaysonservermon command.
2. If you want to continue running the servermon component, remove the gstack and pstack command lines from the commands.ini file in both of the following locations:
By taking this action, you ensure that the servermon component does not call the gstack and pstack commands. 

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Document Information

Modified date:
07 October 2019