[Samba] kcc_periodic output

[Elias Pereira]

What other ways would we have of debugging this?

On Thu, Feb 8, 2024 at 5:39 PM Douglas Bagnall <
douglas.bagnall at catalyst.net.nz> wrote:

> On 9/02/24 06:35, Elias Pereira wrote:
> >     for i in $(seq 1 10); do time /usr/sbin/samba_kcc --debug; sleep
> 5;done
> >
> > I ran the command and in one run it lasted more than 2 minutes.
> >
> > I've sent you the file if you'd like to take a look.
>
> To summarise for the list, one of the runs took 3 minutes, and the rest of
> them
> took half a second.
>
> $ grep -A2 real Downloads/kcc_output.txt
> real    2m59.646s
> user    0m0.387s
> sys     0m0.163s
> --
> real    0m0.504s
> user    0m0.413s
> sys     0m0.078s
> --
> real    0m0.496s
> user    0m0.371s
> sys     0m0.112s
> --
> [...]
>
> The debug output of each run is identical.
>
> Looking at the 'user' and 'sys' lines, we can see that samba_kcc wasn't
> doing
> anything extra in those 3 minutes. It was just waiting. For what, I don't
> know.
>
> Douglas
>
>
>
> >
> > On Wed, Feb 7, 2024 at 8:03 PM Douglas Bagnall <
> douglas.bagnall at catalyst.net.nz
> > <mailto:douglas.bagnall at catalyst.net.nz>> wrote:
> >
> >     On 8/02/24 11:17, Elias Pereira wrote:
> >      > Hi Douglas, thanks for the answer!!!
> >      >
> >      >     samba kcc command = /path/to/samba_kcc --debug
> >      >
> >      >
> >      > I ran the command and the result is in the pastebin below, if you
> can
> >      > take a look.
> >      > https://pastebin.com/x6W2yWm7 <https://pastebin.com/x6W2yWm7>
> >     <https://pastebin.com/x6W2yWm7 <https://pastebin.com/x6W2yWm7>>
> >
> >     It looks to me like that was a successful run, but I can't see if it
> was
> >     slow.
> >
> >     If I understand correctly, sometimes it is bad, and sometimes it is
> not.
> >     If you run in a loop, something like
> >
> >     for i in $(seq 1 10); do time /usr/sbin/samba_kcc --debug; sleep
> 5;done
> >
> >     then you might find one that takes more than 40 seconds -- that is
> the
> >     NT_STATUS_IO_TIMEOUT.
> >
> >     Douglas
> >
> >
> >      >
> >      >     But anyway, I don't think this is a samba_kcc specific
> problem, and
> >      > https://bugzilla.samba.org/show_bug.cgi?id=15568
> >     <https://bugzilla.samba.org/show_bug.cgi?id=15568>
> >      >     <https://bugzilla.samba.org/show_bug.cgi?id=15568
> >     <https://bugzilla.samba.org/show_bug.cgi?id=15568>>is due to the
> same
> >      >     underlying issue. I don't know what that is.
> >      >
> >      >
> >      > I opened this bug, but no one has replied yet.
> >      >
> >      >     >> UpdateRefs failed with NT_STATUS_IO_TIMEOUT
> >      >     This is a different replication failure, independent of the
> KCC.
> >      >     samba_kcc works out where the DC should replicate from, and
> the drepl
> >      >     code does the actual replication.
> >      >     Both could fail with network weirdness, or if either the
> local or remote
> >      >     database is locked up for some reason.
> >      >
> >      >
> >      > And how can I debug this problem? I've searched everywhere and
> found
> >      > nothing about it.
> >      >
> >      > On Wed, Feb 7, 2024 at 6:40 PM Douglas Bagnall
> >      > <douglas.bagnall at catalyst.net.nz <mailto:
> douglas.bagnall at catalyst.net.nz>
> >      > <mailto:douglas.bagnall at catalyst.net.nz
> >     <mailto:douglas.bagnall at catalyst.net.nz>>> wrote:
> >      >
> >      >     On 8/02/24 02:11, Elias Pereira via samba wrote:
> >      >      > Any idea how I can debug this?
> >      >
> >      >
> >      >      >>> I don't know the answer to that, but I think setting
> >      >      >>>
> >      >      >>>       samba kcc command = /usr/sbin/samba_kcc -d5
> >      >      >>>
> >      >
> >      >     I looked it up. Actually
> >      >
> >      >              samba kcc command = /path/to/samba_kcc --debug
> >      >
> >      >     *might* produce more interesting results (you'll probably
> want to use
> >      >     `less -R` to view the logs).
> >      >
> >      >     You can run samba_kcc independently -- it should not do any
> harm, but
> >      >     you can use the --readonly flag if you want to be careful.
> >      >
> >      >     But anyway, I don't think this is a samba_kcc specific
> problem, and
> >      > https://bugzilla.samba.org/show_bug.cgi?id=15568
> >     <https://bugzilla.samba.org/show_bug.cgi?id=15568>
> >      >     <https://bugzilla.samba.org/show_bug.cgi?id=15568
> >     <https://bugzilla.samba.org/show_bug.cgi?id=15568>>
> >      >     is due to the same underlying issue. I don't know what that
> is.
> >      >
> >      >      >> [2024/02/02 20:05:17.752322,  0]
> >      >      >>
> >      >
> >
>  ../../source4/dsdb/repl/drepl_out_helpers.c:1300(dreplsrv_update_refs_done)
> >      >      >>    UpdateRefs failed with NT_STATUS_IO_TIMEOUT
> >      >
> >      >     This is a different replication failure, independent of the
> KCC.
> >      >
> >      >     samba_kcc works out where the DC should replicate from, and
> the drepl
> >      >     code does the actual replication.
> >      >
> >      >     Both could fail with network weirdness, or if either the
> local or
> >      >     remote
> >      >     database is locked up for some reason.
> >      >
> >      >      >> What does this part of the code do?
> >      >      >> source4/dsdb/kcc/kcc_periodic.c:790
> >      >
> >      >     That just reports that samba_kcc failed.
> >      >
> >      >     cheers,
> >      >     Douglas
> >      >
> >      >
> >      >
> >      > --
> >      > Elias Pereira
> >
> >
> >
> > --
> > Elias Pereira
>
>

-- 
Elias Pereira