Re: [Aoetools-discuss] Slow transfer speed of AoE

[Ed C. <ed....@ac...>]

Firstly, I don't know.

Secondly, one thing to always check are caching effects.

So you cannot be sure that you're getting 55 or 35 MBps unless you know 
that you're not just measuring reads and writes from RAM.  The kernel, 
if left alone, will aggressively attempt to make sure that's what happens.

Some good tools are the drop_caches file under /proc/sys/vm (with 
documentation in the kernel source, unfortunately), the boot 
parameter("mem=") that allows you to use less than the installed amount 
of RAM, and workloads for testing that include more data than can fit 
into RAM.

On 10/08/2015 02:59 PM, TuxOholic wrote:
> Hi experts
>
> I use Debian Jessie on two Banana-PI with kernel 3.19 and have 
> installed aoe.ko, vblade and aoetools. Both systems are connected by 
> Gbit LAN via a Gbit switch. The MTU is set at 1500 and can't be 
> changed because the Ethernet driver does not support it for that hardware.
>
> Without AoE, when I read/write dataof 1GB size on the other system via 
> nfs, I get speeds of 55 / 35 MB/s respectively. Writing is probably so 
> much slower due to a bug in the Allwinner A20 silicone or somewhere in 
> software.
>
> However, if I map the drive of one system to the other via AoE and do 
> reading/writing to this mapped raw device (/dev/etherd/e0.1), the 
> speeds get very low, typically 21/7 MB/s respectively. Only when 
> rather small amount of data like 150 MB files are transferred, the 
> speed is higher like 35/25 MB/s.
>
> I wonder why AoE is so slow and hope you can tell me what must be 
> changed to get better transfer rates.
>
> Many thanks!
>
> TuxOholic
>
>
>
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