Bit of an odd question, and very hard to search on. What I am doing is copying a file from a mech disk to an ssd on an ubuntu 16.04 system, via smb shares.

The copy works, but it will run at about 80-90Mb/s for a while then drop to zero. It will soon pick up and start again.

I would like to know of any way to determine why this is occurring and if possible fix it. Or suggest a better method than smb.

I have checked the smb log and it is empty.

1 Answer 1


I think your "bottle neck" is your r/w buffer size.

You could try adding the following line to your /etc/samba/smb.conf socket options = TCP_NODELAY IPTOS_LOWDELAY SO_RCVBUF=65536 SO_SNDBUF=65536

Set the buffers to 1073741824 read/write.

Also change the following settings: Enable large read/write Enable use sendfile. Enable extended attribute support These are checked, while Enable store DOS attributes and Enable Asynchronous I/O (AIO)

  • did socket options = TCP_NODELAY IPTOS_LOWDELAY SO_RCVBUF=65536 SO_SNDBUF=65536 use sendfile = true aio read size = 16384 aio write size = 16384
    – Derek
    Oct 19, 2017 at 23:10
  • could not find how to do buffers, I have not had problems with attributes, and did not mount as suggested by the use of these parameters so did not do them. It is much better now, dropping to around 30kps instead of zero. Thanks for your help
    – Derek
    Oct 19, 2017 at 23:12

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