CIFS online check produces high load

Jan 16, 2018

we use CIFS Protocol for Backup, but the check if the Storage is online produces high load on our Samba file servers.

The samba fileserver is bound to our Active Directory, in the log you can see, that the online checker tries an login every 10 seconds:

[2019/01/28 13:46:13.847175, 2] ../source3/param/loadparm.c:2769(lp_do_section)
Processing section "[pool03b_pve-bck-cfw01a]"
[2019/01/28 13:46:13.847368, 2] ../source3/param/loadparm.c:2769(lp_do_section)
Processing section "[pool03b_pve-bck-kp]"
[2019/01/28 13:46:13.847550, 2] ../source3/param/loadparm.c:2769(lp_do_section)
Processing section "[pool03b_pve-backup]"
[2019/01/28 13:46:13.847735, 2] ../source3/param/loadparm.c:2769(lp_do_section)
Processing section "[pool03b_pve-iso]"
[2019/01/28 13:46:13.950122, 2] ../source3/auth/auth.c:305(auth_check_ntlm_password)
check_ntlm_password: authentication for user [pve-backup] -> [pve-backup] -> [AD\pve-backup] succeeded

as we have an large number of Proxmox Servers, which all try to check the load on the File servers goes up:

[root@gar-sv-pool03b samba]# top

top - 13:54:00 up 81 days, 4:29, 1 user, load average: 4.41, 3.78, 3.26
Tasks: 50 total, 2 running, 48 sleeping, 0 stopped, 0 zombie
%Cpu(s): 7.4 us, 3.9 sy, 0.0 ni, 86.6 id, 1.8 wa, 0.0 hi, 0.3 si, 0.0 st
KiB Mem : 49278476 total, 11101584 free, 16559780 used, 21617112 buff/cache
KiB Swap: 15572988 total, 15473916 free, 99072 used. 15107436 avail Mem

17221 root 20 0 4113036 2.049g 2.047g R 63.7 4.4 0:03.15 smbd
17225 root 20 0 4106644 923324 920844 S 57.3 1.9 0:01.72 smbd
17224 root 20 0 4106644 921372 918892 S 56.7 1.9 0:01.70 smbd
17228 root 20 0 2918128 5876 3404 S 22.7 0.0 0:00.68 smbd
8782 pve-bac+ 20 0 4120428 1.611g 1.608g S 1.3 3.4 172:30.98 smbd
8764 root 20 0 2913048 2.326g 2.324g S 0.3 4.9 308:14.99 smbd

It is no option to switch to NFS for the backup, as this kicks the proxmox HA Nodes.

As I can guess your samba server is running in a VM on one node !?

I think is ok that any of yours node to check if your samba srv is online or not.

What is strange is the fact that auth for samba/ad is not successful at the first try. I can only guess that could be only a high network load and/or io vdisk problem.

Anyway maybe some monitoring tools will show if my suppositions are true ore not. But in any case it will be wise to have a dedicated network for backups and even better the backup system to be outside/external of proxmox enviroment.

If you have problems through the login you should use password caching on the samba server to reduce the load on the AD.
Or use "guest" user instead of an auth through LDAP user.
The samba Server is running on a different dedicated hardware ( it is running there in a container for some reasons, but the whole hardware is dedicated for storage)

guest user is definitly no solution for security reasons, but I will look into password caching


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