Core files were found: smbd.core - SMD service down

Software & Web Applications
1

This happens the second time now:

New alerts:
* The following system core files were found: smbd.core. Please create a ticket
at https://ixsystems.atlassian.net/ and attach the relevant core files along
with a system debug. Once the core files have been archived and attached to
the ticket, they may be removed by running the following command in shell: ‘rm
/var/db/system/cores/*’.

I can see that the /var volume is small

Filesystem Size Used Avail Capacity Mounted on
boot-pool/ROOT/13.0-U6.8 5.5G 1.3G 4.2G 24% /
devfs 1.0K 1.0K 0B 100% /dev
tmpfs 32M 9.5M 22M 30% /etc
tmpfs 4.0M 8.0K 4.0M 0% /mnt
tmpfs 2.6G 2.6G 0B 100% /var
fdescfs 1.0K 1.0K 0B 100% /dev/fd

and full with config DBs:
/var/db/system/configs-…

18.2 MiB [##################] /TrueNAS-12.0-U8.1
18.0 MiB [################# ] /TrueNAS-13.0-U6.7
16.0 MiB [############### ] /TrueNAS-13.0-U6.1
12.6 MiB [############ ] /TrueNAS-13.0-U5.3
9.4 MiB [######### ] /TrueNAS-13.0-U4
7.3 MiB [####### ] /TrueNAS-13.0-U6.2
6.5 MiB [###### ] /TrueNAS-13.0-U6.8
5.5 MiB [##### ] /TrueNAS-12.0-U8
4.4 MiB [#### ] /TrueNAS-13.0-U5.2
4.1 MiB [#### ] /TrueNAS-13.0-U6.4

Is this normal?

I have no idea why smbd has crashed. A reboot helped last time but the problem came back roughly after 1 week.

I am seeing a lot of No space left on device and NT_STATUS_DISK_FULL in log.smbd

The pool volumes are far from 100% full.
/var/run/samba/fd is at 100%.

Any ideas?

2

I moved myself and many client off of Core as while back so I don’t have a reference system to look at, but I would dig deeper into the samba logs to hopefully find the cause.

3

@xerxes, I dont know what the issue is but my /var is just 1%. This is Truenas Core 13.0

root@truenas[~]# df
Filesystem                                               1K-blocks     Used  Avail Capacity  Mounted on
boot-pool/ROOT/13.0-U6.8                                  11756408  1575736    10180672    13%    /
devfs                                                            1        1      0   100%    /dev
tmpfs                                                        32768    10460  22308    32%    /etc
tmpfs                                                         4096        8   4088     0%    /mnt
tmpfs                                                      5565764    378165527948     1%    /var
fdescfs                                                          1        1      0   100%    /dev/fd
zpool                                                  22441014686      151 22441014535     0%    /mnt/zpool
zpool/share                                            22532769648 91755113 22441014535     0%    /mnt/zpool/share
zpool/.system                                          22441014709      174 22441014535     0%    /var/db/system
zpool/.system/cores                                        1048576      1391048436     0%    /var/db/system/cores
zpool/.system/samba4                                   22441015285      750 22441014535     0%    /var/db/system/samba4
zpool/.system/syslog-342111fac902458e8468ba3ccee40d16  22441026782    12247 22441014535     0%    /var/db/system/syslog-342111fac902458e8468ba3ccee40d16
zpool/.system/rrd-342111fac902458e8468ba3ccee40d16     22441089998    75463 22441014535     0%    /var/db/system/rrd-342111fac902458e8468ba3ccee40d16
zpool/.system/configs-342111fac902458e8468ba3ccee40d16 22441132854   118319 22441014535     0%    /var/db/system/configs-342111fac902458e8468ba3ccee40d16
zpool/.system/webui                                    22441014674      139 22441014535     0%    /var/db/system/webui
zpool/.system/services                                 22441014674      139 22441014535     0%    /var/db/system/services
fdescfs                                                          1        1      0   100%    /var/run/samba/fd
4

Thank you, the weird thing is that I cannot find the files that are taking up that much space…

I had this once with a VM when some nfs mounts did work, the system wrote to the local fs. Later when the NFS mount worked, the local data was hidden “under” the mounted nfs share…

5

Hi @xerxes! I assume you are using current TrueCommand 3.2. I’m just started testing this soft since december 2025 (Local Installation, not Cloud service). I have 4 same TrueNAS Core 13 installation and 2 of them was connected to TrueCommand. Every 2-4 weeks this 2 servers have samba service crashed with your sympthoms. And yes, tmpfs mounted to /var space is exhausted. Restart is my solutions. 2 another system (without TrueCommand connect) have uptime to one year. So i think it’s a bug of current TrueCommand. System, based on TrueNAS 25.10 don’t have this bug.

So my solution - i will not used control soft that can crash controled systems. Will see to Zabix side…

1 Like
6

Wow this is gold. Thanks for this lead I. I am actually using TrueCommand and I will shut it down to see if the problem goes away. Rebooting the files is too much hassle and I barely use TrueCommand at all - also because I am running Zabbix, which also monitors my TrueNAS instances.

I have shut down TrueCommand and have rebooted the TrueNas instances that had smbd core files. If the issue returns, I will post it here. If you don’t hear anything from me here, the issue is gone.

7

Thanks, but please write here if steel no such errors for month later. May be something bring it to Truecommand team. Truenas Core not support now. But for me it’s still nice choice becouse i need only perfect clean NAS solutions

8

The /var/run/samba/fd hitting 100% is the actual culprit rather than the pool storage itself — Samba accumulates file descriptors over time and eventually runs out, which then crashes smbd and generates that core dump. Old config backups piling up in /var/db/system are worth cleaning out too, but clearing the fd directory or bumping the file descriptor limit is what stops the weekly reboots from becoming your new normal.