samba - Apr 2018 - What is the maximum speed for download from a samba share

What is the maximum speed for download from a samba share?

I have a 100 kbit/s Internet

The maximum speed for a download from my  webserver with samba is about 
25.000 kbit/s

The bottleneck is the samba access.  Without samba  I can download with 
100 kbit/s

So the question? is it possible to get more speed or is this the maximum 
speed with samba?

I tried a lot of hints for samba tuning but nothing was faster.


Kind regards Knut

Knut Krüger via samba wrote:
> What is the maximum speed for download from a samba share?
>
> I have a 100 kbit/s Internet
>
> The maximum speed for a download from my  webserver with samba is about 
> 25.000 kbit/s
>
> The bottleneck is the samba access.  Without samba  I can download with 
> 100 kbit/s
>
> So the question? is it possible to get more speed or is this the maximum 
> speed with samba?
>
> I tried a lot of hints for samba tuning but nothing was faster.
>   
100 kbit/s?  as in 12.2KB/s?  Ouch.
I was able to get 125mB on writes and 119mB reads using a 1gbit ethernet.
I start to lose speed on 10gb with limiting factor being cpu on
client OR server depending on packet size.

Sent a recent note to the cygwin list (used cygwin in the testing).


My experience was to use the cifs protocol as easiest (over a local
network).  With a 10Gb (limited to 8Gb due to running on older
PCIe interface) card, I'm getting:

/h> bin/iotest
Using bs=16.0M, count=64, iosize=1.0G
R:1073741824 bytes (1.0GB) copied, 1.67486 s, 611MB/s
W:1073741824 bytes (1.0GB) copied, 4.01592 s, 255MB/s
....

Also, on a local net, using Jumbo packets also helps
(I have a 9000B MTU on my local net).

The speeds / values using 'Bytes', (2**3) use the base2
prefixes for consistency.  To get values in mbits, multiple
by 8.388608.

The above test only tests transfer speed -- not file i/o --
it uses /dev/zero for a source and /dev/null for a target.

To simplify testing, I created devices 'zero' and 'null'
in my home directory:
(on linux):
>  > ll zero null
crwxrw-rw- 1 1, 3 May 20  2016 null
crw-rw-rw- 1 1, 5 Jun 15  2015 zero
(on cygwin):
/h> ll zero null
-rwxrw-rw- 1 0 May 20  2016 null*
-rw-rw-rw- 1 0 Jun 15  2015 zero

For write, I used cygwin's 'dd' with if=/dev/zero and of=/h/null.
For read, I used if=/h/zero and of=/dev/null.

Flags for reading: iflag=fullblock conv=nocreat
  and for writing: oflag=direct iflag=fullblock conv=nocreat,notrunc

To test the CPU bounding, I just tried limiting the clock speeds
on the client and server.

Limiting the linux-server's max cpu-speed had
the most affect on performance:
(limited to 1.6GHz instead of 2.4GHz) (33% limitation)

Using bs=16.0M, count=256, iosize=4.0G (~35% slowdown)
R:4294967296 bytes (4.0GB) copied, 10.4467 s, 392MB/s
W:4294967296 bytes (4.0GB) copied, 21.5026 s, 190MB/s

Limiting the client (cygwin-win7sp1x64): (~7-13% slowdown)
(clock limited to 1.16GHz instead of 3.2)

Using bs=16.0M, count=256, iosize=4.0G
R:4294967296 bytes (4.0GB) copied, 7.14355 s, 573MB/s
W:4294967296 bytes (4.0GB) copied, 15.9781 s, 256MB/s

This would indicate that even in the unencrypted case
network transfer speed is cpu bound (and this is using
Jumbo packets).  Using scp or rsync+ssh, speeds dropped to
between 100-200MB/s in either direction.

W/o encryption, I'd expect samba to get near line speeds over
a 100kb connection as that shouldn't come close to being CPU bound.

Am 21.04.2018 um 05:54 schrieb L A Walsh:
> Knut Krüger via samba wrote:
>> What is the maximum speed for download from a samba share?
>>
>> I have a 100 kbit/s Internet
>>
Sorry 100.000 Kbits

> Limiting the linux-server's max cpu-speed had
> the most affect on performance:
> (limited to 1.6GHz instead of 2.4GHz) (33% limitation)
The server is equipped with an 6 core / 12 tread 3.6 GHz CPU (Intel Core 
i7-980x   and  a Raid 10 Disk array.
The cpu is 90% idle (including webserver traffic and mailserver traffic) 
during downloads.

There is no encryption because the samba VM it is over vpn  (I get fulls 
speed with FTP over VPN)

For the rest I will test your hints.


Kind Regards Knut