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Re^2: Time::HiRes strange behavior

by golden.radish (Initiate)
on Feb 06, 2010 at 02:22 UTC ( #821691=note: print w/replies, xml ) Need Help??

in reply to Re: Time::HiRes strange behavior
in thread Time::HiRes strange behavior

This is a great suggestion, rubasov, and it works well except for one thing.
When I use this on a CIFS or SMB mounted filesystem, it reloads (and re-"tails") the entire file each time it changes. On a local filesystem, it works fine. So it looks like I have to port the whole thing over to run locally under Windows. :(
However, I do appreciate the response, it's definitely helped.
I've also tried using tail -s with a value less than 1.0, and while it appears to accept the value, it doesn't actually change the behavior in any way I can see.

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Re^3: Time::HiRes strange behavior
by rubasov (Friar) on Feb 06, 2010 at 12:26 UTC

    Hmm, I never tried to use it on CIFS shares, however this definitely seems to me a bug in SMBFS/CIFS. Have you really tried with both of them? (AFAIK they do not share much of code lines, so it can be that in one of them the bug is not present.)

    After a little googling I found this thread, where someone claims to workaround a similar problem by mounting the CIFS share with the directio mount option. Though I don't know whether this can be recommended in a production system (how stable it is, how much it hurts performance). Anyway you may give it a try.

    Hope that helps.
      Yep, it doesn't work at all without 'directio' as an option at mount time, even just trying to tail from the shell.
      However, I was able to get it to work 99.993% of the time (tested with 20,000+ lines) by altering the File::Tail option 'reset_tail' to 1.
      That provides the expected behavior, for the moment. There are rare occasions when log lines are duplicated, such as when there are more than 9-10 events per second. However that is rare with my data stream, so this will be good enough for now.

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