[Samba] How to diagnose a busy LDAP server process in the Samba AD DC

Andrew Bartlett abartlet at samba.org
Tue Apr 2 19:28:08 UTC 2024 

1.5 seconds is pretty long, I would look into what those queries are.  
I would also look into repeated queries, sometimes these things are
clients stuck in a loop where they don't complete because they expect
some termination condition. 
Andrew Bartlett
On Tue, 2024-04-02 at 09:25 -0300, Elias Pereira via samba wrote:
> The saga continues...
> I've spent a whole day with log level 5 and 7 and no error. All I
> have todo is return the log to the default and the error reappears.
> I monitored the "LDAP Query: Duration", but I didn't notice any
> crashes inthe queries.
> I don't know if it's a long time, but some queries took 1.5s.
> Is there anything else I can do?
> On Mon, Mar 25, 2024 at 1:30 PM Elias Pereira <empbilly at gmail.com>
> wrote:
> > Hello Andrew,
> > What's the explanation for when the log level is set to 5, the
> > errorNT_STATUS_IO_TIMEOUT doesn't appear, but when it's at the
> > default loglevel, it does?
> > On Mon, Mar 18, 2024 at 10:33 AM Elias Pereira <empbilly at gmail.com>
> > wrote:
> > > hi Andrew, thanks for the help!!!
> > > It seems to me the LDAP process being busy would be the root
> > > cause here.
> > > > Working out what is going on here shouldn't is a detective task
> > > > - I alwaysstart with a wireshark trace.  The client making all
> > > > the noise/traffic willbe the one causing the trouble.
> > > 
> > > In the wireshark analysis, should I filter only by the ldap
> > > protocol orleave everything? Should I look at something specific
> > > in the client logs?
> > > On Sun, Mar 10, 2024 at 9:31 PM Andrew Bartlett <
> > > abartlet at samba.org>wrote:
> > > > Thanks for getting back to me.
> > > > It seems to me the LDAP process being busy would be the root
> > > > causehere.  Working out what is going on here shouldn't is a
> > > > detective task - Ialways start with a wireshark trace.  The
> > > > client making all thenoise/traffic will be the one causing the
> > > > trouble.
> > > > If it isn't clear from that, then look into the DB audit
> > > > logging forperhaps busy writes
> > > > 
> > > > https://wiki.samba.org/index.php/Setting_up_Audit_Logging#Enabling_AD_DC_Database_Audit_Logging
> > > > 
> > > > Finally, set 'log level = 5' and look for logs like: LDAP
> > > > Query:Duration was
> > > > This will tell you about how long each query is taking,
> > > > potentiallyshowing a particularly slow query that needs to be
> > > > stopped.
> > > > Andrew Bartlett
> > > > On Sun, 2024-03-10 at 19:46 -0300, Elias Pereira wrote:
> > > > Is the drepl local processes very busy doing inbound
> > > > replication?
> > > > 
> > > > How can I check this?
> > > > My instinct is either the server is very busy (and this should
> > > > show upin CPU use) or a transaction is being held open
> > > > excessively.
> > > > 
> > > > I use VMs on Proxmox. In DC1, I installed the Proxmox agent,
> > > > and CPUusage via the dashboard is very low. However, when I
> > > > checked using 'top,'the LDAP process is consuming around 94/96%
> > > > of the CPU. Very strange.
> > > > 
> > > > It is probably 94% of a single CPU, but you might have 8 CPUs
> > > > in the VM,so overall use is low.
> > > > The VM has 4 CPUs and 6GB of memory.
> > > > 
> > > > 
> > > > On Sun, Mar 10, 2024 at 5:55 PM Andrew Bartlett <
> > > > abartlet at samba.org>wrote:
> > > > Either the local server is busy, or possibly (but it would not
> > > > explainthe samba_kcc) Samba's drepl process is stuck talking to
> > > > a remote server.
> > > > Is the drepl local processes very busy doing inbound
> > > > replication?
> > > > My instinct is either the server is very busy (and this should
> > > > show upin CPU use) or a transaction is being held open
> > > > excessively.
> > > > Andrew Bartlett
> > > > On Sat, 2024-03-09 at 19:11 -0300, Elias Pereira via samba
> > > > wrote:
> > > > I've been grappling with a recurring set of errors for quite
> > > > some time now:
> > > > - UpdateRefs failed with NT_STATUS_IO_TIMEOUT
> > > > - Failed samba_kcc - NT_STATUS_IO_TIMEOUT
> > > > - IRPC callback failed for DsReplicaSync - NT_STATUS_IO_TIMEOUT
> > > > 
> > > > Despite cranking up the log level to 10, the returned
> > > > information remains
> > > > frustratingly cryptic and hard to decipher.
> > > > 
> > > > This error, being overly generic, continues to elude
> > > > identification even
> > > > with
> > > > the heightened log verbosity. The challenge lies in tracing its
> > > > origin.
> > > > 
> > > > Running samba-tool dbcheck doesn't reveal any problems, yet
> > > > executing the
> > > > command while monitoring the Samba log with "tail -f" exposes
> > > > errors
> > > > identical
> > > > to those described above.
> > > > 
> > > > Interestingly, samba-tool drs showrepl doesn't report any
> > > > errors.
> > > > 
> > > > So, what additional steps can be taken to unearth the root
> > > > cause
> > > > of these persistent NT_STATUS_IO_TIMEOUT errors?
> > > > 
> > > > 
> > > > On Fri, Mar 1, 2024 at 10:32 PM Elias Pereira <
> > > > empbilly at gmail.com
> > > > 
> > > > > wrote:
> > > > 
> > > > There is probably nothing wrong with your log, but Firefox
> > > > doesn't
> > > > like it, it thinks it contains a virus.
> > > > 
> > > > 
> > > > I just saw now that your response ended up in spam, probably
> > > > because of
> > > > the link with the log. O.o
> > > > 
> > > > I still receive the error in the logs:
> > > > source4/dsdb/kcc/kcc_periodic.c:790: Failed samba_kcc -
> > > > NT_STATUS_IO_TIMEOUT
> > > > 
> > > > The strangest thing is that it occurs when the command is
> > > > executed:
> > > > samba-tool dbcheck --cross-ncs --fix --yes
> > > > 
> > > > Could it be some object causing this error?
> > > > 
> > > > On Mon, Feb 12, 2024 at 4:40 PM Rowland Penny via samba <
> > > > samba at lists.samba.org
> > > > 
> > > > > wrote:
> > > > 
> > > > On Mon, 12 Feb 2024 16:20:27 -0300
> > > > Elias Pereira via samba <
> > > > samba at lists.samba.org
> > > > 
> > > > > wrote:
> > > > 
> > > > hi,
> > > > 
> > > > My saga continues...
> > > > 
> > > > I've configured the audit log for drs_repl in smb.conf, and
> > > > below is
> > > > the log generated.
> > > > https://transfer.sh/7fen4qCNIQ/drs_repl.log
> > > > 
> > > > 
> > > > 
> > > > The log level was 5.
> > > > drs_repl:5@/var/log/samba/drs_repl.log
> > > > 
> > > > Could someone take a look and help me understand the log?
> > > > 
> > > > 
> > > > There is probably nothing wrong with your log, but Firefox
> > > > doesn't
> > > > like it, it thinks it contains a virus.
> > > > 
> > > > Rowland
> > > > 
> > > > 
> > > > 
> > > > --
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> > > > instructions:
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> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > --
> > > > Elias Pereira
> > > > 
> > > > 
> > > > 
> > > > --
> > > > Elias Pereira
> > > > --
> > > > 
> > > > Andrew Bartlett (he/him)       https://samba.org/~abartlet/
> > > > Samba Team Member (since 2001) https://samba.org
> > > > Samba Team Lead                
> > > > https://catalyst.net.nz/services/samba
> > > > Catalyst.Net Ltd
> > > > Proudly developing Samba for Catalyst.Net Ltd - a Catalyst IT
> > > > groupcompany
> > > > Samba Development and Support: 
> > > > https://catalyst.net.nz/services/samba
> > > > 
> > > > Catalyst IT - Expert Open Source Solutions
> > > > 
> > > > 
> > > > 
> > > > --Elias Pereira
> > > > --
> > > > Andrew Bartlett (he/him)       https://samba.org/~abartlet/
> > > > Samba Team Member (since 2001) https://samba.org
> > > > Samba Team Lead                
> > > > https://catalyst.net.nz/services/samba
> > > > Catalyst.Net Ltd
> > > > Proudly developing Samba for Catalyst.Net Ltd - a Catalyst IT
> > > > groupcompany
> > > > Samba Development and Support: 
> > > > https://catalyst.net.nz/services/samba
> > > > 
> > > > Catalyst IT - Expert Open Source Solutions
> > > > 
> > > > 
> > > 
> > > --Elias Pereira
> > 
> > --Elias Pereira
> 
> -- Elias Pereira
-- 
Andrew Bartlett (he/him)       https://samba.org/~abartlet/Samba Team Member (since 2001) https://samba.orgSamba Team Lead                https://catalyst.net.nz/services/sambaCatalyst.Net Ltd
Proudly developing Samba for Catalyst.Net Ltd - a Catalyst IT group
company
Samba Development and Support: https://catalyst.net.nz/services/samba
Catalyst IT - Expert Open Source Solutions

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