Transfer rate when accessing Samba share from Mac OS X
I use my Cubietruck as a Samba server. Some day I noticed the transfer rate when copying files from my Mac with OS X El Captian was only around 10 MB/s. As the Cubietruck has a gigabit ethernet port the transfer rate should be much higher. I also remembered the transfer rate to be around 30 MB/s in the past. Not as fast as gigabit can deliver but I guess CPU load is a factor here.
After some research on the internet I found a configuration which got me back to ca. 30 MB/s. OS X uses SMB Signing since Mac OS X 10.11.5 by default. You can view the Samba version and options currently used for connected shares with the tool smbutil:
Mini:~ johannes$ smbutil statshares -a
==================================================================================================
SHARE ATTRIBUTE TYPE VALUE
==================================================================================================
media
SERVER_NAME cubie
USER_ID 502
SMB_NEGOTIATE AUTO_NEGOTIATE
SMB_VERSION SMB_3.0
SMB_SHARE_TYPE DISK
SIGNING_SUPPORTED TRUE
EXTENDED_SECURITY_SUPPORTED TRUE
LARGE_FILE_SUPPORTED TRUE
CLIENT_REQUIRES_SIGNING TRUE
FILE_IDS_SUPPORTED TRUE
DFS_SUPPORTED TRUE
MULTI_CREDIT_SUPPORTED TRUE
ENCRYPTION_SUPPORTED TRUE
SIGNING_ON TRUE
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The line “SIGNING_ON TRUE” indicates that SMB Signing is used. You can change this setting in the file ~/Library/Preferences/nsmb.conf:
Mini:~ johannes$ echo "[default]" >> ~/Library/Preferences/nsmb.conf; echo "signing_required=no" >> ~/Library/Preferences/nsmb.conf Mini:~ johannes$ cat ~/Library/Preferences/nsmb.conf [default] signing_required=no
After restarting your Mac or disconnecting all shares and reconnecting afterwards SMB Signing should be deactivated (SIGNING_ON is no longer shown):
Mini:~ johannes$ smbutil statshares -a
==================================================================================================
SHARE ATTRIBUTE TYPE VALUE
==================================================================================================
media
SERVER_NAME cubie
USER_ID 502
SMB_NEGOTIATE AUTO_NEGOTIATE
SMB_VERSION SMB_3.0
SMB_SHARE_TYPE DISK
SIGNING_SUPPORTED TRUE
EXTENDED_SECURITY_SUPPORTED TRUE
LARGE_FILE_SUPPORTED TRUE
FILE_IDS_SUPPORTED TRUE
DFS_SUPPORTED TRUE
MULTI_CREDIT_SUPPORTED TRUE
ENCRYPTION_SUPPORTED TRUE
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To get back to the original configuration you can just delete the file ~/Library/Preferences/nsmb.conf.
As an alternative to deactivating SMB Signing globally in ~/Library/Preferences/nsmb.conf you can also connect your share with cifs://hostname instead of smb://hostname. This way Samba version 1 without SMB Signing is used:
Mini:~ johannes$ smbutil statshares -a
==================================================================================================
SHARE ATTRIBUTE TYPE VALUE
==================================================================================================
pyload
SERVER_NAME cubie
USER_ID 502
SMB_NEGOTIATE SMBV_NEG_SMB1_ONLY
SMB_VERSION SMB_1
SMB_SHARE_TYPE UNKNOWN
EXTENDED_SECURITY_SUPPORTED TRUE
UNIX_SUPPORT TRUE
LARGE_FILE_SUPPORTED TRUE
CLIENT_REQUIRES_SIGNING TRUE
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