High CPU Load on Synology by smbd

First, this seems a common problem with DS213j and DSM 5.1+. Someone reported that after a reboot, the problem went away: have you tried it?

From your top data, it seems that the CPU is busy with system time, ie: doing some syscall. Try changing the following parameters in the smb.conf file and then restart the NAS:

• change notify = no
• kernel change notify = no
• server max protocol = NT1
• client max protocol = NT1

Does they change anything?

I had also the same problem with :

• random slow load problem when I navigate into folder with Windows Explorer
• hight CPU usage by the smbd process (~50%) when the random problem that talk about before append
• poor speed performance when I transfert file between my Windows computer and my Nas (< 25 MB/s with gigabite connection...)

I solved these 3 problems by simply switching SMB2 to SMB 3 in:

Config Panel > Files services > Win/Mac/NFS panel > Advanced settings in Windows part > Max protocole => Enable SMB 3

I hope these solve your problems too :)