[Samba] Server RAM filling up when writing to share from macOS

Marius Steffen privat at mariussteffen.de
Sun May 31 22:41:57 UTC 2020


I noticed an absolutely work-breaking behavior in Samba 4.12 (not present in 4.11 or lower): when writing to a share (Arch Linux server) from macOS, smbd’s RAM usage is going up pretty much exactly the size of the transferred files - and is released *only* when the connection is completely closed. So obviously, when keeping the share mounted, copying files finally leads to Samba eating up all of my server’s memory, finally crashing.

After some fiddling, I discovered this happens whenever either ’smb encrypt’, ’server signing’ or SMB2 are forced/required by the server. Again: this only happens with Samba 4.12.

Of course, this renders my Samba shares completely unusable - any idea what to do?

Here’s my testparm output:

Load smb config files from /etc/samba/smb.conf
Loaded services file OK.

Press enter to see a dump of your service definitions

# Global parameters
	log file = /var/log/samba/%m.log
	map to guest = Bad User
	security = USER
	server string = marius-arch Samba Server
	idmap config * : backend = tdb
	smb encrypt = required

	path = /home/marius
	read only = No
	valid users = marius

Best regards,
Marius Steffen
privat at mariussteffen.de

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