Re: Writing to a log file without colliding

[pingo]

It should be mentioned that using locks over NFS is bound to end in disappointment, but then again, maybe you aren't. :-)

May work if you are using some new-fangled NFS version, though.

[amw1]

If you are trying to lock a file that's on NFS create a file in a local directory (/tmp perhaps) and do the locks on that file to control access to the NFS file.

[pingo]

Assuming, of course, that the script is only run on one machine. Nitpicking? Yes. :-)

[Your Mother]

I don't know if I've been led correctly on the point but I believe lock-file creation/destruction isn't enough. I think a lock-dir creation/destruction is best for NFS situations (better atomicity from what I've been told).

[amw1]

locking over NFS is usually pretty sketchy regardless of wether it's a lock on a file or a directory. Unix really doesn't make a huge distinction between a file and a directory anyway, so the atomicness (I love making up words) of a lock on a file vs. directory should be the same.

There are some NFS server appliances that don't use a unix file system (NetApp for one) where the atomicness may differ a bit.

It's been quite a long time since I've played with anything other than sharing home directories on NFS so some of my thinking is most likely dated. :)