[Beowulf] (no subject)

Nathan Moore ntmoore at gmail.com
Fri Feb 16 06:50:57 PST 2007

Hello all,

I have a small beowulf cluster of Scientific Linux 4.4 machines with  
common NIS logins and NFS shared home directories.  In the short  
term, I'd rather not buy a tape drive for backups.  Instead, I've got  
a jury-rigged backup scheme.  The node that serves the home  
directories via NFS runs a nightly tar job (through cron),
	root at server> tar cf home_backup.tar ./home
	root at server> mv home_backup.tar /data/backups/

where /data/backups is a folder that's shared (via NFS) across the  
cluster.  The actual backup then occurs when the other machines in  
the cluster (via cron) copy home_backup.tar to a private (root-access- 
only) local directory.

	root at client> cp /mnt/server-data/backups/home_backup.tar /private_data/

where "/mnt/server-data/backups/" is where the server's "/data/ 
backups/" is mounted, and where /private_data/ is a folder on  
client's local disk.

Here's the problem I'm seeing with this scheme.  users on my cluster  
have quite a bit of stuff stored in their home directories, and  
home_backup.tar is large (~4GB).  When I try the cp command on  
client, only 142MB of the 4.2GB is copied over (this is repeatable -  
not a random error, and always about 142MB).  The cp command doesn't  
fail, rather, it quits quietly.  Why would only some of the file be  
copied over?  Is there a limit on the size of files which can be  
transferred via NFS?  There's certainly sufficient space on disk for  
the backups (both client's and server's disks are 300GB SATA drives,  
formatted to ext3)

I'm using the standard NFS that's available in SL43, config is  
basically default.

Nathan Moore

- - - - - - - - - - - - - - - - - - - - - - -
Nathan Moore
Physics, Pasteur 152
Winona State University
nmoore at winona.edu
- - - - - - - - - - - - - - - - - - - - - - -

More information about the Beowulf mailing list