Large files / Linux

[Kelly Higgins]

This earlier message might help, although I have not tried it myself:

Date: Fri, 13 Jul 2001 18:13:04 +0100
From: Matt Hodges <pczmph at unix.ccc.nottingham.ac.uk>
To: molpro-user at tcpc3.bham.ac.uk
Subject: 2GB file size limit on GNU/Linux.

The matter of how to circumvent the 2GB file size limit on GNU/Linux
(x86) has been raised once or twice, but I've never seen a
satisfactory solution.

The key to getting this working, at least with a 2.4.5 kernel and
version 2.2.3 of glibc, is to replace the 32-bit file system interface
with the 64-bit interface. One way to achieve this[1] is to compile
the C sources with the _FILE_OFFSET_BITS macro defined as 64. Thus,
the only departure needed from the usual configure/build/install
procedure is to use the following in the CONFIG file:

CC="cc -D_FILE_OFFSET_BITS=64"

I have tested this with a calculation on H2O..Ne at the HF/aug-cc-pVQZ
level of theory, which needs about 5GB of disk and which previously
failed. Comparison was made with the same calculation run on Tru64
UNIX V5.1.

I didn't find this solution on searching the archives, so I hope this
is of use to others as well as to myself.

Footnotes:
[1]  I don't know if Large File Support is optional in glibc; this
     fix will fail if this is the case and it isn't built in.

--
Matt Hodges
School of Chemistry
Nottingham University


On Sat, 15 Sep 2001, Dr. Pablo Wessig wrote:

>Dear MOLPRO users,
>we are runnning MOLPRO with Linux (Suse 7.2) and we have serious problems
>with large CAS jobs. The jobs always die with a message like:
>
>wrabsf: Error in writing to file T1100000605.TMP (unit 11), 8192 words at
>word offset 268431360
>
>It is still enought disk space available but it seems that MOLPRO cannot
>create files > 2 GB !
>The output of the 'ulimit -a' command is:
>
>core file size (blocks)     0
>data seg size (kbytes)      unlimited
>file size (blocks)          unlimited
>max locked memory (kbytes)  unlimited
>max memory size (kbytes)    unlimited
>open files                  1024
>pipe size (512 bytes)       8
>stack size (kbytes)         unlimited
>cpu time (seconds)          unlimited
>max user processes          8190
>virtual memory (kbytes)     unlimited
>
>Obviously, there is no limit of the file size. Does anybody know what is
>the reason of this strange behavior? Is it possible that there is a "hard
>limit" of max. file size in the linux kernel? Unfortunately, I have not
>found any appropriate option.
>
>Very thanks for any help
>Pablo
>
>
>__________________________________________________
>
>  Priv.-Doz. Dr. Pablo Wessig                           
>  Institut fuer Chemie                       
>  Humboldt-Universitaet zu Berlin            
>  Hessische Str. 1-2                         
>  D-10115 Berlin                             
>  Tel. 030/20937 275                         
>  Fax. 030/20936 940                        
>  e-mail:  pablo.wessig at chemie.hu-berlin.de      
>  www:     http://141.20.74.18/wessig
>
>  Please do not use the following address any longer:
>  pablo=wessig at rz.hu-berlin.de        
>___________________________________________________
>
>