number of process or users that can access the same file

infusino · 11-27-2002, 09:45 AM

need help...

does any know how many processes can open RW the same file whether it be a linux file under NFS mount or a novell server file under NCPFS.

thanks ,,,

DavidPhillips · 11-27-2002, 07:54 PM

infusino · 11-28-2002, 09:42 AM

how about in readonly

DavidPhillips · 11-28-2002, 09:55 AM

actually I think it would depend on file locking, If it's not locked then they would be able to open it., but I think that's why they have file locking.

infusino · 11-28-2002, 10:05 AM

So there isn't any limit to the number of processes or users that can open a file "only in readonly" whether it was mounted on NFS or NCPFS?

DavidPhillips · 11-28-2002, 10:43 AM

Not really sure if there is a limit. I would think everything has some kind of limit though.

there is the nolock option if you want them to open it as read write though

DavidPhillips · 11-28-2002, 10:50 AM

this is sort of interesting, Not sure what you intention is but you might want to read this

Quota WARNINGS

PLEASE, PLEASE ATTEND TO WARNING MESSAGES!
You risk losing data if you exceed your quota. Output to a home directory which is over quota will be truncated. Files moved to such a directory will also be truncated. Just opening a file for editing while you are over quota can cause the loss of the entire file's contents. Unfortunately, these are results of the Unix implementation of quota and can be prevented only by user attention to quota warnings.

Avoid having batch jobs attempt to write to home directory space that has exceeded disk space quota:

* You will get truncated or zero length files and waste the run whose output is lost as a result.
* You will lose further data if your home directory remains filled after the job finishes, if you attempt to copy, write or edit files.
* MULTIPLE ATTEMPTS TO WRITE TO A DIRECTORY THAT IS OVER QUOTA WILL CREATE A SIGNIFICANT BURDEN ON THE NFS SERVER, CAUSING INTERACTIVE DELAY AND PERFORMANCE PROBLEMS. In some cases, jobs create hundreds of thousands of write attempts, quota checks, and refusals to write within a few minutes.

Avoid having batch jobs write to filled home directories:

* Write job output to file systems that are better suited for this use and that have no quota limit:
o /usr/tmp local temp space on each node.
o /nfs/tmp* shared NFS temp space on all OCF hosts.
o GPFS file systems on all IBM (parallel) systems.
* Check your quota usage and limits with "quota" or "quota -v".
* Watch your login messages for a warning when your usage exceeds 90 percent of the quota allowance.