Is it trying to read or change a file which may be offline (i.e. contents have been transferred to tape)?
Remember that on some filesystems, older files are automatically migrated to tape. For batch jobs, remember to check that the files required to be accessible are online, as described in the Quick start instructions. Another frequent scenario is the use of scp or sftp to transfer old data off the system – in both cases, offline files will be recalled individually on their first access, which is very inefficient and slow (the same tape will probably load and unload many times). The commands dmfind or dmls are DMF-aware versions of find and ls respectively, which can be used to locate or list the DMF-state of migrated files. Here is how to efficiently recall an entire directory in preparation for submitting a job or running a command which will need to access the files there.
