SATA port multiplier support

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ZFS without ECC RAM is crap. If your data has any value then use the freely available implementations that ensure 'end to end data integrity'. For example ReFS on Windows, btrfs on Linux or ZFS on Solaris/FreeBSD. On hardware that features at least simple ECC RAM (advanced ECC RAM would be better). The Banana Pi/Pro or any other cheap NAS is not part of this category.

Edited by Mr_Palmtree at Mon Jan 19, 2015 20:18

Hello Community,
Hello developers of Bananian,

For several months I have quietly watched and followed the forums here while playing with my bananapi and testing out every new inage that comes around.

To simplify everything, I am currently running this:

Bananapi Lubuntu

Port Multiplier with 5 Sata disks
Usb drive for the downloads so moving a file to its final destinatiin doesnt put load on the PMP.


All good and well

But Lubuntu doesnt support this nice pmp setup either.

Two question arise:

1) is there an easy way to do the recompile that you guys did, but then to the Lubuntu kernel?
2) are you (developers) going to include a bananian-configue option to enable or disable the pmp support in the kernel

more and more demands for this functionality arise, and if you were to implement this even without the need of a recompilation, I am immediately changing distro's to the awesome dark side of bananian.

Please get back to me as soon as you have time!



Edited by tkaiser at Tue Jan 20, 2015 04:44

If I were you I would simply wait a few weeks/months.

Currently the kernel needs a little patch for PMP functionality to work. And if patched in this way it's not possible to use a directly connected SATA disk. This won't change in kernel 3.4.x (that is what Lubuntu currently uses). Some kernel hackers had a look into it and thought about implementing this feature as a so called kernel module in recent kernel versions (mainline, currently 3.19). So sometimes in the future it would be an easy one to switch between both modes which would make it possible to provide this as a simple switch in a configuration user interface.

Hopefully in the meantime also some long term experiences with cheap crappy port multiplier setups will be made and published.

I just realized that at least with 3.19.0-rc5 a connected PM gets detected automagically so that no patches seems to be required because the necessary code is already inside sunxi_ahci. Just did a test with an el cheapo JMB321 PM and read performance decreased from approx. 200 MB/sec to approx. 135 MB/sec when accessing a single disk behind the PM: ... 11857&pid=61492

When multiple disks are involved this will get worse.

Thanks for getting back to me.

I don't really care about the read performance dropping, as long as it stays high enough for single disk access each time (I only access one disk per session, sometimes two)

I stream over a gigabit network to another device running Kodi, so the BPi is solely a file and download server.

I don't mind learning how to compile a kernel, and by the looks of it, for this to work today, I am going to have to compile my own kernel and switch to bananian...

Ah well, off to the images!



I did some further testing that showed that the read performance drops do not affect NAS performance since in this situation the network is the bottleneck.

And there's no need to recompile the kernel if you start with mainline. Igor's images are ready for that. You can download a ready to run image with kernel 3.19.0-rc4 and Wheezy, Jessie or Ubuntu Trusty:

Igor also supplies separate kernel images that were generated using the same build scripts so if kernel development evolved you might be able to simply exchange the kernel with a more mature version. And as far as I know he started to work on an upgrade mechanism to update the image from within the running system without losing settings/data (comparable to 'bananian-update').

But since all you need is an additional SD card and some time to spend on learning either way is worth a walk

tkaiser replied at Tue Jan 20, 2015 06:58
I did some further testing that showed that the read performance drops do not affect NAS performance ...

great job here....

but for the uninitiated bpi owners like me, while i got the wheezy image from Igor's site with the 3.19.0 kernel up and wokring, need to be shown the way to get the rc4 of this kernel to get pm going. i am using a cfi-bxx53pm backplane. where do i find it?

Edited by tkaiser at Thu Mar 5, 2015 10:33
dherajjotwani replied at Thu Mar 5, 2015 06:12
need to be shown the way to get the rc4 of this kernel to get pm going

You could use this kernel package I built using Igor's scripts a few days ago (unfortunately already using 4.0.0-rc1):

I outlined how I built the kernel and what you've to do to configure it for PM mode here:

tkaiser replied at Thu Mar 5, 2015 10:33
You could use this kernel package I built using Igor's scripts a few days ago (unfortunately alrea ...

super duper...

thanks for the prompt reply and your kernel. will download and give it a go and report back.

hey thanks @tkaiser

booted with ur kernel. added the config file for enabling pm. and bingo !!! so now i have openmediavault based network storage supporting 5 disks... fantastic !!!

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