BackupPC-users

Re: [BackupPC-users] BackupPC fails with aborted by signal=PIPE, Can't write to socket

2017-01-19 22:58:31
Subject: Re: [BackupPC-users] BackupPC fails with aborted by signal=PIPE, Can't write to socket
From: John Spitzer <johned9999 AT comcast DOT net>
To: "General list for user discussion, questions and support" <backuppc-users AT lists.sourceforge DOT net>
Date: Thu, 19 Jan 2017 19:57:46 -0800
On 01/19/2017 1:28 PM, Les Mikesell wrote:
On Thu, Jan 19, 2017 at 2:25 PM, John Spitzer <johned9999 AT comcast DOT net> 
wrote:

The most likely suspect is that rsync timeout shown in the log snippet
you posted.  But you didn't provide any details about why or how your
rsync had timeouts enabled.

That rsync timeout is being set 'under the hood'. I can't tell from the logs I've captured already if it's set by BackupPC or the NAS or if the timeout is occurring for the writes to the pipe between the client/server processes or server and network driver to the NAS. I suspect the latter because of the following data extracted from strace. This data was taken for a run that failed. strace was attached to the two BackupPC_dump processes that were running. You can see that the reads were occurring from the NAS share (/media/Backup/BackupPC/pc/...) and a write process [write(9<socket:[258436]>,] to a socket received the EPIPE signal. There's also an alarm(72000) that may be significant.
-------
5677 12:37:51.243532 read(6</media/Backup/BackupPC/pc/johned-linux-vbox/5/fDrive1/f.virtualbox/fMachines/fWin 10 Pro x64 VM07/fWin 10 Pro x64 VM07-disk1.vdi>, <unfinished ...>
5671    12:37:51.244472    alarm(72000)      = 72000
5671 12:37:51.244625 select(16, [7<socket:[259570]>], [9<socket:[258436]>], [7<socket:[259570]> 9<socket:[258436]>], NULL) = 1 (out [9]) 5671 12:37:51.244804 write(9<socket:[258436]>, "\330\24\352\332U\367\0214?\213=tP \v6\271TV\31z\342X\271\220/\326\"x\355\345\37"..., 35328) = -1 EPIPE (Broken pipe) 5671 12:37:51.244912 --- SIGPIPE {si_signo=SIGPIPE, si_code=SI_USER, si_pid=5671, si_uid=122} ---
5671    12:37:51.244946    rt_sigreturn()    = -1 EPIPE (Broken pipe)
5
------
I've attached a file with more of the trace. I have a much longer file with the last 10 minutes of the run before the failure. The rsync process always fails two or three seconds longer than 300 seconds. I was hoping that someone with knowledge of the internals of BackupPC could chime in and shed some light on what's happening and why.

Attachment: strace-06.txt
Description: Text document

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