some problems with osm-fr overpass-api instance

classic Classic list List threaded Threaded
6 messages Options
Reply | Threaded
Open this post in threaded view
|

some problems with osm-fr overpass-api instance

marc marc
Hello,

1) root cause of the crash
we didn't find the root cause of the crash
log extract:
Sep 12 18:54:00 osm147 dispatcher[27374]: File_Error No such file or
directory 2 /ssd/overpass/database//osm3s_v0.7.54_osm_base Unix_Socket::7

but the file /ssd/overpass/database//osm3s_v0.7.54_osm_base exist

2) dirname missing in some log entry
Sep 12 19:17:26 osm147 rules_loop.sh[99]: runtime error: open64: 2 No
such file or directory /osm3s_v0.7.54_osm_base Dispatcher_Client::1
Sep 12 19:17:28 osm147 dispatcher[844]: File_Error Address already in
use 98 /ssd/overpass/database//osm3s_v0.7.54_osm_base Unix_Socket::4
Sep 12 19:17:28 osm147 dispatcher[846]: File_Error No such file or
directory 2 /osm3s_v0.7.54_osm_base Dispatcher_Client::1

3) diff problem : "node not found"
Rodolph remove the socket, restart the server, remove the lock
that prevent the process to start. request are working, update
are running but I see several lines like :
Sep 12 19:54:02 osm147 fetch_osc_and_apply.sh[10522]: 2017-09-12
19:54:02
URL:https://planet.osm.org/replication/minute/002/619/669.osc.gz 
[197403/197403] -> "/tmp/osm-3s_update_pN9aiF/002619669.osc.gz" [1]
Sep 12 20:04:33 osm147 fetch_osc_and_apply.sh[10522]: Reading XML file
... finished reading nodes. Flushing to database ...... done.
Sep 12 20:04:34 osm147 fetch_osc_and_apply.sh[10522]: Reading XML file
... finished reading ways. Version 2 has a later or equal timestamp
(2017-09-12T19:00:51Z) than version 3 (2017-09-12T19:00:51Z) of Way 71962472
Sep 12 20:14:13 osm147 fetch_osc_and_apply.sh[10522]: Node 5101567155
used in way 6059604 not found.
<cut a lot of line with "node not found">
Sep 12 20:30:39 osm147 fetch_osc_and_apply.sh[10522]: Flushing to
database ...... done.

logs are using UTC time.

Regards,
Marc
mmd
Reply | Threaded
Open this post in threaded view
|

Re: some problems with osm-fr overpass-api instance

mmd
Hi

in your Munin stats I noticed that Nginx reported 34 requests/s at the time when the update process stopped (which coincidentally matches the number I found out in Perf tests, so the dispatcher was maxed out for what is possible w/ 0.7.54).

It looks like you need to set up rate limiting for Overpass and maybe also check transaction.log to see what happened at that time. Can you provide more details on this?

Problem 3 below probably means you need to start with a fresh db, especially due to the node not found messages.

In any case more complete log files would be helpful.

Cheers 

marc marc <[hidden email]> schrieb am Mi. 13. Sep. 2017 um 16:52:
Hello,

1) root cause of the crash
we didn't find the root cause of the crash
log extract:
Sep 12 18:54:00 osm147 dispatcher[27374]: File_Error No such file or
directory 2 /ssd/overpass/database//osm3s_v0.7.54_osm_base Unix_Socket::7

but the file /ssd/overpass/database//osm3s_v0.7.54_osm_base exist

2) dirname missing in some log entry
Sep 12 19:17:26 osm147 rules_loop.sh[99]: runtime error: open64: 2 No
such file or directory /osm3s_v0.7.54_osm_base Dispatcher_Client::1
Sep 12 19:17:28 osm147 dispatcher[844]: File_Error Address already in
use 98 /ssd/overpass/database//osm3s_v0.7.54_osm_base Unix_Socket::4
Sep 12 19:17:28 osm147 dispatcher[846]: File_Error No such file or
directory 2 /osm3s_v0.7.54_osm_base Dispatcher_Client::1

3) diff problem : "node not found"
Rodolph remove the socket, restart the server, remove the lock
that prevent the process to start. request are working, update
are running but I see several lines like :
Sep 12 19:54:02 osm147 fetch_osc_and_apply.sh[10522]: 2017-09-12
19:54:02
URL:https://planet.osm.org/replication/minute/002/619/669.osc.gz
[197403/197403] -> "/tmp/osm-3s_update_pN9aiF/002619669.osc.gz" [1]
Sep 12 20:04:33 osm147 fetch_osc_and_apply.sh[10522]: Reading XML file
... finished reading nodes. Flushing to database ...... done.
Sep 12 20:04:34 osm147 fetch_osc_and_apply.sh[10522]: Reading XML file
... finished reading ways. Version 2 has a later or equal timestamp
(2017-09-12T19:00:51Z) than version 3 (2017-09-12T19:00:51Z) of Way 71962472
Sep 12 20:14:13 osm147 fetch_osc_and_apply.sh[10522]: Node 5101567155
used in way 6059604 not found.
<cut a lot of line with "node not found">
Sep 12 20:30:39 osm147 fetch_osc_and_apply.sh[10522]: Flushing to
database ...... done.

logs are using UTC time.

Regards,
Marc
Reply | Threaded
Open this post in threaded view
|

Re: some problems with osm-fr overpass-api instance

marc marc
Yes incoming rate was very hight.
but fastcgi was limited to 1 req during the peak (we raise it to 4)
Of course It 'll be better to add a true rate limite on ngix, we 'll
check it.

I sent you transaction.log
I am unfortunately unable to find what is abnormal in addition
to the extract paste in the previous email.

to fix the db issue, should the current db be deleted or can it be
repaired with a diff id created before the problem starts ?

Regards,
Marc

Le 13. 09. 17 à 22:24, mmd a écrit :

> Hi
>
> in your Munin stats I noticed that Nginx reported 34 requests/s at the
> time when the update process stopped (which coincidentally matches the
> number I found out in Perf tests, so the dispatcher was maxed out for
> what is possible w/ 0.7.54).
>
> It looks like you need to set up rate limiting for Overpass and maybe
> also check transaction.log to see what happened at that time. Can you
> provide more details on this?
>
> Problem 3 below probably means you need to start with a fresh db,
> especially due to the node not found messages.
>
> In any case more complete log files would be helpful.
>
> Cheers
>
> marc marc <[hidden email] <mailto:[hidden email]>>
> schrieb am Mi. 13. Sep. 2017 um 16:52:
>
>     Hello,
>
>     1) root cause of the crash
>     we didn't find the root cause of the crash
>     log extract:
>     Sep 12 18:54:00 osm147 dispatcher[27374]: File_Error No such file or
>     directory 2 /ssd/overpass/database//osm3s_v0.7.54_osm_base
>     Unix_Socket::7
>
>     but the file /ssd/overpass/database//osm3s_v0.7.54_osm_base exist
>
>     2) dirname missing in some log entry
>     Sep 12 19:17:26 osm147 rules_loop.sh[99]: runtime error: open64: 2 No
>     such file or directory /osm3s_v0.7.54_osm_base Dispatcher_Client::1
>     Sep 12 19:17:28 osm147 dispatcher[844]: File_Error Address already in
>     use 98 /ssd/overpass/database//osm3s_v0.7.54_osm_base Unix_Socket::4
>     Sep 12 19:17:28 osm147 dispatcher[846]: File_Error No such file or
>     directory 2 /osm3s_v0.7.54_osm_base Dispatcher_Client::1
>
>     3) diff problem : "node not found"
>     Rodolph remove the socket, restart the server, remove the lock
>     that prevent the process to start. request are working, update
>     are running but I see several lines like :
>     Sep 12 19:54:02 osm147 fetch_osc_and_apply.sh[10522]: 2017-09-12
>     19:54:02
>     URL:https://planet.osm.org/replication/minute/002/619/669.osc.gz
>     [197403/197403] -> "/tmp/osm-3s_update_pN9aiF/002619669.osc.gz" [1]
>     Sep 12 20:04:33 osm147 fetch_osc_and_apply.sh[10522]: Reading XML file
>     ... finished reading nodes. Flushing to database ...... done.
>     Sep 12 20:04:34 osm147 fetch_osc_and_apply.sh[10522]: Reading XML file
>     ... finished reading ways. Version 2 has a later or equal timestamp
>     (2017-09-12T19:00:51Z) than version 3 (2017-09-12T19:00:51Z) of Way
>     71962472
>     Sep 12 20:14:13 osm147 fetch_osc_and_apply.sh[10522]: Node 5101567155
>     used in way 6059604 not found.
>     <cut a lot of line with "node not found">
>     Sep 12 20:30:39 osm147 fetch_osc_and_apply.sh[10522]: Flushing to
>     database ...... done.
>
>     logs are using UTC time.
>
>     Regards,
>     Marc
>

mmd
Reply | Threaded
Open this post in threaded view
|

Re: some problems with osm-fr overpass-api instance

mmd
Hi,

Overpass API has its own rate limiting mechanism which works independent of the web server in use. This can be activated via osm3s_query command with a rate limit command line parameter (see command usage for exact syntax, which I don't recall without a system around). It is based on a leaky bucket algo and should avoid such large amounts of requests in a very short timeframe.

Unfortunately deleting the db looks like the way to go, as it's probably inconsistent and we don't know to which extent.

I'll take a look at the log files in the next days, maybe send those files to Roland as well.

Cheers 

marc marc <[hidden email]> schrieb am Do. 14. Sep. 2017 um 00:21:
Yes incoming rate was very hight.
but fastcgi was limited to 1 req during the peak (we raise it to 4)
Of course It 'll be better to add a true rate limite on ngix, we 'll
check it.

I sent you transaction.log
I am unfortunately unable to find what is abnormal in addition
to the extract paste in the previous email.

to fix the db issue, should the current db be deleted or can it be
repaired with a diff id created before the problem starts ?

Regards,
Marc

Le 13. 09. 17 à 22:24, mmd a écrit :
> Hi
>
> in your Munin stats I noticed that Nginx reported 34 requests/s at the
> time when the update process stopped (which coincidentally matches the
> number I found out in Perf tests, so the dispatcher was maxed out for
> what is possible w/ 0.7.54).
>
> It looks like you need to set up rate limiting for Overpass and maybe
> also check transaction.log to see what happened at that time. Can you
> provide more details on this?
>
> Problem 3 below probably means you need to start with a fresh db,
> especially due to the node not found messages.
>
> In any case more complete log files would be helpful.
>
> Cheers
>
> marc marc <[hidden email] <mailto:[hidden email]>>
> schrieb am Mi. 13. Sep. 2017 um 16:52:
>
>     Hello,
>
>     1) root cause of the crash
>     we didn't find the root cause of the crash
>     log extract:
>     Sep 12 18:54:00 osm147 dispatcher[27374]: File_Error No such file or
>     directory 2 /ssd/overpass/database//osm3s_v0.7.54_osm_base
>     Unix_Socket::7
>
>     but the file /ssd/overpass/database//osm3s_v0.7.54_osm_base exist
>
>     2) dirname missing in some log entry
>     Sep 12 19:17:26 osm147 rules_loop.sh[99]: runtime error: open64: 2 No
>     such file or directory /osm3s_v0.7.54_osm_base Dispatcher_Client::1
>     Sep 12 19:17:28 osm147 dispatcher[844]: File_Error Address already in
>     use 98 /ssd/overpass/database//osm3s_v0.7.54_osm_base Unix_Socket::4
>     Sep 12 19:17:28 osm147 dispatcher[846]: File_Error No such file or
>     directory 2 /osm3s_v0.7.54_osm_base Dispatcher_Client::1
>
>     3) diff problem : "node not found"
>     Rodolph remove the socket, restart the server, remove the lock
>     that prevent the process to start. request are working, update
>     are running but I see several lines like :
>     Sep 12 19:54:02 osm147 fetch_osc_and_apply.sh[10522]: 2017-09-12
>     19:54:02
>     URL:https://planet.osm.org/replication/minute/002/619/669.osc.gz
>     [197403/197403] -> "/tmp/osm-3s_update_pN9aiF/002619669.osc.gz" [1]
>     Sep 12 20:04:33 osm147 fetch_osc_and_apply.sh[10522]: Reading XML file
>     ... finished reading nodes. Flushing to database ...... done.
>     Sep 12 20:04:34 osm147 fetch_osc_and_apply.sh[10522]: Reading XML file
>     ... finished reading ways. Version 2 has a later or equal timestamp
>     (2017-09-12T19:00:51Z) than version 3 (2017-09-12T19:00:51Z) of Way
>     71962472
>     Sep 12 20:14:13 osm147 fetch_osc_and_apply.sh[10522]: Node 5101567155
>     used in way 6059604 not found.
>     <cut a lot of line with "node not found">
>     Sep 12 20:30:39 osm147 fetch_osc_and_apply.sh[10522]: Flushing to
>     database ...... done.
>
>     logs are using UTC time.
>
>     Regards,
>     Marc
>

mmd
Reply | Threaded
Open this post in threaded view
|

Re: some problems with osm-fr overpass-api instance

mmd
In reply to this post by marc marc
Am 13.09.2017 um 16:52 schrieb marc marc:

> Hello,
>
> 1) root cause of the crash
> we didn't find the root cause of the crash
> log extract:
> Sep 12 18:54:00 osm147 dispatcher[27374]: File_Error No such file or
> directory 2 /ssd/overpass/database//osm3s_v0.7.54_osm_base Unix_Socket::7
>
> but the file /ssd/overpass/database//osm3s_v0.7.54_osm_base exist
>


According to the transaction.log file you sent me, something strange
happened at 2017-09-12 18:45:32 - the dispatcher got (re)started,
possibly because the dispatcher process died at that time for some
reason. Do you see anything interesting in dmesg pointing to a crashed
process?

Ansible tries to start it again every 5 seconds afterwards, but this
won't work as long as there are stale lock files around. That's why
there's a large number of "Dispatcher just started" further down in the
log file.

2017-09-12 18:45:25 [28205] request_read_and_idx of process 11597
timeout 180 space 536870912.
2017-09-12 18:45:25 [28205] read_finished of process 11594.
2017-09-12 18:45:25 [11597] request_read_and_idx() end
2017-09-12 18:45:25 [11594] read_finished() end
2017-09-12 18:45:25 [11597] read_idx_finished() start
2017-09-12 18:45:25 [28205] waited idle for 2 cycles.
2017-09-12 18:45:25 [28205] read_idx_finished 11597.
2017-09-12 18:45:25 [11597] read_idx_finished() end
2017-09-12 18:45:25 [11597]
(way["natural"="water"]["tidal"!="yes"](38,-2,39,-1););(._;>>;);out meta;
2017-09-12 18:45:26 [11572] write_commit() start 6546 12873 1823 9642 1379
2017-09-12 18:45:26 [28205] waited idle for 13 cycles.
2017-09-12 18:45:26 [28205] write_commit of process 11572.
2017-09-12 18:45:26 [11572] write_commit() end
2017-09-12 18:45:26 [28205] waited idle for 5 cycles.
2017-09-12 18:45:26 [28205] read_aborted of process 11572.
2017-09-12 18:45:26 [11610] write_start() start version=''
2017-09-12 18:45:26 [28205] waited idle for 5 cycles.
2017-09-12 18:45:26 [28205] write_start of process 11610. Considered as
reading: 11597.
2017-09-12 18:45:26 [11610] write_start() end
2017-09-12 18:45:32 [28205] waited idle for 58 cycles.
2017-09-12 18:45:32 [11667] Dispatcher just started.
2017-09-12 18:45:33 [11597] read_finished() start 394 0 0 0
2017-09-12 18:45:33 [11597] Dispatcher_Client::read_finished::socket
/osm3s_v0.7.54_osm_base 32 Broken pipe
2017-09-12 18:45:37 [12204] Dispatcher just started.
2017-09-12 18:45:42 [12334] Dispatcher just started.
2017-09-12 18:45:47 [12465] Dispatcher just started.
2017-09-12 18:45:53 [12602] Dispatcher just started.
2017-09-12 18:45:58 [12731] Dispatcher just started.
2017-09-12 18:46:03 [12860] Dispatcher just started.
2017-09-12 18:46:08 [12991] Dispatcher just started.
2017-09-12 18:46:14 [13130] Dispatcher just started.
2017-09-12 18:46:19 [13308] Dispatcher just started.
2017-09-12 18:46:24 [13443] Dispatcher just started.
2017-09-12 18:46:29 [13757] Dispatcher just started.
2017-09-12 18:46:35 [14125] Dispatcher just started.
2017-09-12 18:46:40 [14256] Dispatcher just started.
2017-09-12 18:46:45 [14387] Dispatcher just started.
2017-09-12 18:46:50 [14513] Dispatcher just started.
2017-09-12 18:46:56 [14666] Dispatcher just started.
2017-09-12 18:47:01 [14794] Dispatcher just started.
2017-09-12 18:47:06 [14925] Dispatcher just started.
2017-09-12 18:47:11 [15076] Dispatcher just started.
2017-09-12 18:47:17 [15213] Dispatcher just started.
2017-09-12 18:47:22 [15341] Dispatcher just started.
2017-09-12 18:47:27 [15492] Dispatcher just started.
2017-09-12 18:47:29 [11996] waited idle for 361928 cycles.
2017-09-12 18:47:32 [15641] Dispatcher just started.
2017-09-12 18:47:49 [16132] Dispatcher just started.
2017-09-12 18:47:54 [16268] Dispatcher just started.
2017-09-12 18:48:00 [16428] Dispatcher just started.
2017-09-12 18:48:05 [16560] Dispatcher just started.
2017-09-12 18:48:10 [16704] Dispatcher just started.
2017-09-12 18:48:15 [16838] Dispatcher just started.
2017-09-12 18:48:21 [16985] Dispatcher just started.
2017-09-12 18:48:26 [17129] Dispatcher just started.
2017-09-12 18:48:31 [17268] Dispatcher just started.
2017-09-12 18:48:36 [17406] Dispatcher just started.
2017-09-12 18:48:42 [17556] Dispatcher just started.
2017-09-12 18:48:47 [17700] Dispatcher just started.
2017-09-12 18:48:52 [17849] Dispatcher just started.
2017-09-12 18:48:57 [17996] Dispatcher just started.
2017-09-12 18:49:03 [18151] Dispatcher just started.
2017-09-12 18:49:08 [18295] Dispatcher just started.
2017-09-12 18:49:13 [18443] Dispatcher just started.
2017-09-12 18:49:18 [18579] Dispatcher just started.
2017-09-12 18:49:24 [18727] Dispatcher just started.
2017-09-12 18:49:29 [18859] Dispatcher just started.
2017-09-12 18:49:34 [18992] Dispatcher just started.
2017-09-12 18:49:39 [19164] Dispatcher just started.
2017-09-12 18:49:45 [19362] Dispatcher just started.
2017-09-12 18:49:50 [19494] Dispatcher just started.
2017-09-12 18:49:55 [19634] Dispatcher just started.
2017-09-12 18:50:00 [19761] Dispatcher just started.
2017-09-12 18:50:05 [19893] Dispatcher just started.
2017-09-12 18:50:11 [20035] Dispatcher just started.
2017-09-12 18:50:16 [20172] Dispatcher just started.
2017-09-12 18:50:21 [20310] Dispatcher just started.
2017-09-12 18:50:26 [20495] Dispatcher just started.
2017-09-12 18:50:32 [20877] Dispatcher just started.
2017-09-12 18:50:37 [21196] Dispatcher just started.
2017-09-12 18:51:25 [22624] Dispatcher just started.
2017-09-12 18:51:30 [22776] Dispatcher just started.
2017-09-12 18:51:35 [22927] Dispatcher just started.
2017-09-12 18:51:41 [23089] Dispatcher just started.
2017-09-12 18:51:46 [23247] Dispatcher just started.
2017-09-12 18:51:51 [23398] Dispatcher just started.
2017-09-12 18:51:56 [23550] Dispatcher just started.
2017-09-12 18:52:02 [23713] Dispatcher just started.
2017-09-12 18:52:07 [23884] Dispatcher just started.
2017-09-12 18:52:12 [24044] Dispatcher just started.
2017-09-12 18:52:17 [24201] Dispatcher just started.
2017-09-12 18:52:23 [24363] Dispatcher just started.
2017-09-12 18:52:28 [24524] Dispatcher just started.
2017-09-12 18:52:33 [24673] Dispatcher just started.
2017-09-12 18:52:38 [24826] Dispatcher just started.
2017-09-12 18:52:44 [24996] Dispatcher just started.
2017-09-12 18:52:49 [25161] Dispatcher just started.
2017-09-12 18:52:54 [25321] Dispatcher just started.
2017-09-12 18:52:57 [25446] Dispatcher just started.
2017-09-12 18:53:02 [25600] Dispatcher just started.
2017-09-12 18:53:07 [25757] Dispatcher just started.
2017-09-12 18:53:12 [25918] Dispatcher just started.
2017-09-12 18:53:18 [26088] Dispatcher just started.
2017-09-12 18:53:23 [26249] Dispatcher just started.
2017-09-12 18:53:28 [26400] Dispatcher just started.
2017-09-12 18:53:33 [26553] Dispatcher just started.
2017-09-12 18:53:39 [26718] Dispatcher just started.
2017-09-12 18:53:44 [26884] Dispatcher just started.
2017-09-12 18:53:49 [27042] Dispatcher just started.
2017-09-12 18:53:54 [27200] Dispatcher just started.
2017-09-12 18:54:00 [27371] Dispatcher just started.
2017-09-12 18:54:05 [27533] Dispatcher just started.
2017-09-12 18:54:10 [27687] Dispatcher just started.
2017-09-12 18:54:15 [27842] Dispatcher just started.
2017-09-12 18:54:21 [28005] Dispatcher just started.
2017-09-12 18:54:26 [28169] Dispatcher just started.
2017-09-12 18:54:31 [28338] Dispatcher just started.
2017-09-12 18:54:36 [28503] Dispatcher just started.
2017-09-12 18:54:42 [28676] Dispatcher just started.
2017-09-12 18:54:47 [28840] Dispatcher just started.
2017-09-12 18:54:52 [29003] Dispatcher just started.
2017-09-12 18:54:57 [29167] Dispatcher just started.
2017-09-12 18:55:03 [29338] Dispatcher just started.
2017-09-12 18:55:08 [29507] Dispatcher just started.
2017-09-12 18:55:13 [29666] Dispatcher just started.
2017-09-12 18:55:18 [29829] Dispatcher just started.
2017-09-12 18:55:24 [29997] Dispatcher just started.
2017-09-12 18:55:29 [30159] Dispatcher just started.
2017-09-12 18:55:59 [31548] Dispatcher just started.
2017-09-12 18:55:59 [31552] request_read_and_idx() start
2017-09-12 18:55:59 [31548] request_read_and_idx of process 31552
timeout 180 space 536870912.
2017-09-12 18:55:59 [31552] request_read_and_idx() end
2017-09-12 18:55:59 [31552] read_idx_finished() start
2017-09-12 18:55:59 [31548] waited idle for 1 cycles.
2017-09-12 18:55:59 [31548] read_idx_finished 31552.
2017-09-12 18:55:59 [31552] read_idx_finished() end
2017-09-12 18:55:59 [31552]

Reply | Threaded
Open this post in threaded view
|

Re: some problems with osm-fr overpass-api instance

marc marc
Hello,

Le 15. 09. 17 à 11:23, mmd a écrit :

> Am 13.09.2017 um 16:52 schrieb marc marc:
>> 1) root cause of the crash
>> we didn't find the root cause of the crash
>> log extract:
>> Sep 12 18:54:00 osm147 dispatcher[27374]: File_Error No such file or
>> directory 2 /ssd/overpass/database//osm3s_v0.7.54_osm_base Unix_Socket::7
>> but the file /ssd/overpass/database//osm3s_v0.7.54_osm_base exist
>
> According to the transaction.log file you sent me, something strange
> happened at 2017-09-12 18:45:32 - the dispatcher got (re)started,
> possibly because the dispatcher process died at that time for some
> reason. Do you see anything interesting in dmesg pointing to a crashed
> process?
Yes, at 18:45, the service didn't work already anymore
and Rodolph restarted it.
Sep 12 18:45:32 osm147 systemd[1]: Stopping Overpass dispatcher...
Sep 12 18:45:32 osm147 systemd[1]: Stopped Overpass dispatcher.
Sep 12 18:45:32 osm147 systemd[1]: Started Overpass dispatcher.
the cause of the first problem occurred before 18:45
I have not seen anything interesting in dmesg, nor in systemd log.

starting at 18:45, the problem was :
Sep 12 18:45:32 osm147 dispatcher[11667]: File_Error Address already in
use 98 /ssd/overpass/database//osm3s_v0.7.54_osm_base Unix_Socket::4
Sep 12 18:45:32 osm147 dispatcher[11668]: File_Error Connection refused
111 /ssd/overpass/database//osm3s_v0.7.54_osm_base Unix_Socket::7

and after a few minutes
Sep 12 18:52:28 osm147 dispatcher[24524]: File_Error File exists 17
/osm3s_v0.7.54_osm_base Dispatcher_Server::1
Sep 12 18:52:28 osm147 dispatcher[24525]: File_Error No such file or
directory 2 /ssd/overpass/database//osm3s_v0.7.54_osm_base Unix_Socket::7
but the file /ssd/overpass/database//osm3s_v0.7.54_osm_base exist
I don't understand why dispatcher[24524] found the file but can't use it
and at the same time dispatcher[24525] doesn't see the file

Regards,
Marc