[Bioclusters] recompiling redhat source rpms from .spec files to add large file support?

[Donald Becker]

On Wed, 8 May 2002, Goran Ceric wrote:

>> Support for large files has been in modern kernels and filesystems for a
>> while now. What I constantly run into though are programs that bomb out
>> when faced with large files. Particularly when I'm trying to build large
>> blast databases :)

We implemented LFS (Large File Summit) support for the 2.2 kernels in
our earlier Scyld Beowulf releases.  Thanks to support from Alexa, we
did a thorough test of the system with large files.  It was several
weeks of work to test and fix the file utilities with both sparse and
dense large files.  (When Red Hat later released LFS support in their
Enterprise distribution, we noted that they obviously missed that the
kernel handles sparse and dense files differently.)

We found surprisingly few bugs in the GNU utilities.  Most of the
changes were in adding long offsets to programs such as split and ftp.
It's not very rewarding finding so few specific bugs -- no one thinks
that you did the work!

> I had problems with tcsh under RedHat 7.2. It didn't work with large files.
> Bash worked fine.

Earlier bash versions (v1.2) did not work correctly.  People typically
ask "why would a shell care":
    cat < large-file | wc

> I also had to recompile perl to include large files
> support. I remember having some trouble with Reiserfs over NFS and large
> files on Redhat's 2.4.9-10 kernel. Hope this helps a little.

NFS v2 only supports 32 bit file offsets in the protocol, and I wouldn't
count on more than 31 bits.  NFS v3 does have 64 bit offset support.

-- 
Donald Becker				becker@scyld.com
Scyld Computing Corporation		http://www.scyld.com
410 Severn Ave. Suite 210		Second Generation Beowulf Clusters
Annapolis MD 21403			410-990-9993