samba - Apr 2024 - How to diagnose a busy LDAP server process in the Samba AD DC

The saga continues...

I've spent a whole day with log level 5 and 7 and no error. All I have to
do is return the log to the default and the error reappears.

I monitored the "LDAP Query: Duration", but I didn't notice any
crashes in
the 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 error
> NT_STATUS_IO_TIMEOUT doesn't appear, but when it's at the default
log
> level, 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 always
>>> start with a wireshark trace.  The client making all the
noise/traffic will
>>> be the one causing the trouble.
>>
>>
>> In the wireshark analysis, should I filter only by the ldap protocol or
>> leave 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 cause
>>> here.  Working out what is going on here shouldn't is a
detective task - I
>>> always start with a wireshark trace.  The client making all the
>>> noise/traffic will be the one causing the trouble.
>>>
>>> If it isn't clear from that, then look into the DB audit
logging for
>>> perhaps 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, potentially
>>> showing 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
up
>>> in CPU use) or a transaction is being held open excessively.
>>>
>>>
>>> I use VMs on Proxmox. In DC1, I installed the Proxmox agent, and
CPU
>>> usage 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
explain
>>> the 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
up
>>> in 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
>>>
>>>
>>>
>>>
>>> --
>>>
>>> To unsubscribe from this list go to the following URL and read the
>>>
>>> instructions:
>>>
>>> https://lists.samba.org/mailman/options/samba
>>>
>>>
>>>
>>>
>>>
>>> --
>>>
>>> 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 group
>>> company
>>>
>>> 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 group
>>> company
>>>
>>> Samba Development and Support:
https://catalyst.net.nz/services/samba
>>>
>>> Catalyst IT - Expert Open Source Solutions
>>>
>>>
>>>
>>
>> --
>> Elias Pereira
>>
>
>
> --
> Elias Pereira
>

-- 
Elias Pereira

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
> > > > 
> > > > 
> > > > 
> > > > --
> > > > To unsubscribe from this list go to the following URL and
read
> > > > the
> > > > instructions:
> > > > https://lists.samba.org/mailman/options/samba
> > > > 
> > > > 
> > > > 
> > > > 
> > > > 
> > > > --
> > > > 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