[ale] very intermittent weird SCP failure?

[Ed Cashin]

This issue reminds me of an ancient XFS bug, which probably isn't the
problem but made me wonder a bunch of stuff.

  * What filesystem is in use?
  * What storage layers (device mapper, Software RAID, etc.) are beneath it?
  * Has the problem been going on every three months during the whole ten
years?
  * If not, when did it change and can you tell what packages were updated
around that time?


On Mon, Aug 7, 2017 at 12:08 PM, Neal Rhodes <neal at mnopltd.com> wrote:

> We have a client running a ----------------------------- application on
> three linux servers running
>
> Linux HDISATBE3 2.6.32-696.1.1.el6.x86_64 #1 SMP Tue Apr 11 17:13:24 UTC
> 2017 x86_64 x86_64 x86_64 GNU/Linux
>
> The two primary event servers accumulate a file of connection/heartbeat
> activity, and once a week, a crontab job does an SCP of this file to the
> backend server, which imports these two files to calculate uptime.   The
> respective user has ssh host equivalence, so this proceeds without password
> challenge.
>
> This has worked for about 10 years.
>
> Very occasionally, like, once in 3 months, we will find the copied file on
> the backend server is garbled, to wit:
>
> - total size is correct; matches source
> - the first XXX bytes of the file is NULL characters.
>
> Which hoses up everything.   I usually figure out which file is boogered,
> re-do the scp by hand, and re-do the import.  Then all is well.
>
> I am just bumfuzzled as to what would cause this.   It's always on the
> front of the file.
>
> I should check and see exactly how many NULLS, but usually when it happens
> my hair is on fire.   I'm guessing about 512 or 1K.
>
> Neal Rhodes
> MNOP Ltd
>
>
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-- 
  Ed Cashin <ecashin at noserose.net>
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