A story of cron, svn, and STDERR.

[Kevin D. Clark]

Ken D'Ambrosio writes:

> Hey, all.  I ran into an interesting problem that drove me outright
> bonkers and thought I'd share the insights for those who might run into
> similar issues.  Most of my Subversion repositories I just back up via
> straight flat file; one, however, being sent off-site, needs to be backed
> up weekly via "svn dump".  I wrote a small script that does the dump and
> then compresses it.  Tried it from the command line, and it worked like a
> champ.  Plugged it into cron, and it would get somewhere between 40 MB and
> 65 MB in (out of 2.4 GB), and die.  No obvious rhyme or reason.  Clearly,
> it wasn't a permissions or path issue, or I'd get 0 MB in.  Finally, in
> attempting to re-direct STDERR to a log file... I fixed it.  *BY*
> re-directing STDERR to a log file.  Apparently either cron or svn really,
> really wants STDERR (even though no error was being thrown!), and this
> machine didn't have an MTA installed.  At some point, I guess cron or svn
> goes to open up STDERR, for whatever darn reason, can't, and dies.  Either
> installing an MTA (the smart move) or re-directing 2> *anywhere*, did the
> trick.

So, can you confirm, was there anything from stderr in your logfile?
Was the file zero-size at the end of the "svn dump"?

What does your "svn dump" command do when you run it thusly?:

   svn dump 2>&-

(Personally, as a shell-script hacker, I rarely close stderr in this
manner unless I really grok the executable that is being run, because
I do sometimes encounter programs that react poorly when run in this
manner.)

Regards,

--kevin
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