I have an Ubuntu server running at home that is acting as a domain controller for my home network. It is configured as the primary DNS server as well. I have a RAID 1 array mounted (software RAID) as a samba share. When I copy large files to this share, the transfer rate starts out really high. However, after a few seconds it starts to pause temporarily and then start again, resulting in spikes in the transfer rate. Here is a screenshot of what it looks like copying a large file from Windows to the Ubuntu samba share.

enter image description here

A note about the network setup: the two machines are both connected to the same 1Gbps switch. I also have a 1Gbps wired router that the switch is connected to.

It seems like the issue lies on the Ubuntu side, although I can't be sure. Here is my samba configuration:

        workgroup = mydomain
        realm = mydomain.local
        password server = x.x.x.x
        netbios name = my-server-name
        server role = active directory domain controller
        dns forwarder = x.x.x.x
        allow dns updates = nonsecure and secure
        vfs objects = acl_xattr
        map acl inherit = Yes
        store dos attributes = Yes
        socket options = TCP_NODELAY IPTOS_LOWDELAY SO_RCVBUF=65536 SO_SNDBUF=65536
        aio read size = 64360
        aio write size = 64360
        aio write behind = true
        log level = 1

        path = /var/lib/samba/sysvol/mydomain.local/scripts
        read only = No

        path = /var/lib/samba/sysvol
        read only = No

        comment = Archive
        path = /media/archive
        read only = yes
        write list = myadminuser

        comment = Data
        path = /media/data
        read only = yes

My initial thought was that for some reason the disks weren't able to keep up, but from what I've seen in testing the disks on the machine itself, they should be much faster than the network transfer rate.

Any help would be appreciated!

Edit: Here is a video of the io happening on the server. As you can see, samba will just randomly stop writing to the disk. There is nothing else of consequence happening on the server.


  • Boot your windows box with a bootable linux and test again to rule out the linux vs windows. Can be a antivirus scanning the file, etc.. it's a large question – yagmoth555 Jul 29 '15 at 14:21
  • Good thought, I will try that. – SoWeLie Jul 29 '15 at 14:23
  • I set up an ubuntu bootable linux image and the same problem occurs. Interesting note: if I'm copying a smaller file, say something that is less than 1GB the speed remains the same the entire time. With files over a GB, it seems to slow down at the same point (somewhere around 1-2GB). – SoWeLie Jul 30 '15 at 2:15

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