Q. I am running a very large CFX job on a 64 bit UNIX machine and CFX is unable to write the large (well over 2GB) results file. The result of the UNIX "limit" command shows that the file size is unlimited. What could be wrong.

A. There is no limit on a 64 bit Linux/UNIX machine.

If you are writing to a network mounted drive then you should make
sure that the NFS daemon/client software is the 64 bit version.

Also make sure that the file system with which your hard
disks are formatted supports files > 2GB (either networked or not).

Older OSes used 32-bit numbers for storing the length of files, and also
used a negative number as an error indicator: this implies a 2Gb limit (2^31
bytes) on file size, enforced by the OS, and expected by programs.

A few years ago, UNIX vendors produced a new interface for programmers to
access files larger than 2Gb, but of course this can't be used with older
programs, as they only set aside space for a 32-bit file size. So, one way
to get this error is if the application has not been built with support for
these large files. CFX is built with this support.

The other place this change affected was the OS itself: anything which
handles access to files had to be upgraded to support these larger files.
Generally for local filesystems this was easy, but for things such as NFS
which involve multiple computers it's harder to do consistently, and doesn't
always happen by default. So it's quite possible that the OS is simply not
allowing him to write files which are any larger then 2Gb.

Quota problems *should* give a different error, but this does come from the OS too,
and an odd system setup it might not be reporting it properly.

(Info provided by Andy Mortimer and Dan Williams)


Q. I am running a very large CFX job on a 64 bit UNIX machine and CFX is unable to write the large (well over 2GB) results file. The result of the UNIX "limit" command shows that the file size is unlimited. What could be wrong.

A. There is no limit on a 64 bit Linux/UNIX machine.

If you are writing to a network mounted drive then you should make
sure that the NFS daemon/client software is the 64 bit version.

Also make sure that the file system with which your hard
disks are formatted supports files > 2GB (either networked or not).

Older OSes used 32-bit numbers for storing the length of files, and also
used a negative number as an error indicator: this implies a 2Gb limit (2^31
bytes) on file size, enforced by the OS, and expected by programs.

A few years ago, UNIX vendors produced a new interface for programmers to
access files larger than 2Gb, but of course this can't be used with older
programs, as they only set aside space for a 32-bit file size. So, one way
to get this error is if the application has not been built with support for
these large files. CFX is built with this support.

The other place this change affected was the OS itself: anything which
handles access to files had to be upgraded to support these larger files.
Generally for local filesystems this was easy, but for things such as NFS
which involve multiple computers it's harder to do consistently, and doesn't
always happen by default. So it's quite possible that the OS is simply not
allowing him to write files which are any larger then 2Gb.

Quota problems *should* give a different error, but this does come from the OS too,
and an odd system setup it might not be reporting it properly.

(Info provided by Andy Mortimer and Dan Williams)





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