Application program errors

When receiving application program errors, there are various courses of action to take.

Follow these steps to help resolve application program errors:

Loss of file system access usually appears first as an error received by an application. Such errors are normally encountered when the application tries to access an unmounted file system.
The most common reason for losing access to a single file system is a failure somewhere in the path to a large enough number of disks to jeopardize your data if operation continues. These errors may be reported in Operating system error log on any node because they are logged in the first node to detect the error. Check all error logs for errors.

The mmlsmount all -L command can be used to determine the nodes that have successfully mounted a file system.
There are several cases where the state of a given disk subsystem prevents access by GPFS. This instance is seen by the application as I/O errors of various types and is reported in the error logs as MMFS_SYSTEM_UNMOUNT or MMFS_DISKFAIL records. This state can be found by issuing the mmlsdisk command.
If allocation of data blocks or files (which quota limits should allow) fails, issue the mmlsquota command for the user, group or fileset.
If filesets are involved, use these steps to determine which fileset was being accessed at the time of the failure:
1. From the error messages generated, obtain the path name of the file being accessed.
2. Go to the directory just obtained, and use this mmlsattr -L command to obtain the fileset name:
```
mmlsattr -L . | grep "fileset name:"
```
  The system produces output similar to:
```
fileset name: myFileset
```
3. Use the mmlsquota -j command to check the quota limit of the fileset. For example, using the fileset name found in the previous step, issue this command:
```
mmlsquota -j myFileset -e 
```
  The system produces output similar to:
```
                  Block Limits                      |    File Limits
Filesystem type      KB  quota limit in_doubt grace | files quota limit in_doubt grace  Remarks
fs1        FILESET 2152      0     0        0  none |   250     0   250        0  none
```
The mmlsquota output is similar when checking the user and group quota. If usage is equal to or approaching the hard limit, or if the grace period has expired, make sure that no quotas are lost by checking in doubt values.

If quotas are exceeded in the in doubt category, run the mmcheckquota command. For more information, see The mmcheckquota command.
Note: There is no way to force GPFS nodes to relinquish all their local shares in order to check for lost quotas. This can only be determined by running the mmcheckquota command immediately after mounting the file system, and before any allocations are made. In this case, the value in doubt is the amount lost.

To display the latest quota usage information, use the -e option on either the mmlsquota or the mmrepquota commands. Remember that the mmquotaon and mmquotaoff commands do not enable and disable quota management. These commands merely control enforcement of quota limits. Usage continues to be counted and recorded in the quota files regardless of enforcement.

Reduce quota usage by deleting or compressing files or moving them out of the file system. Consider increasing quota limit.