[Best budget device as torrent box?]

Sorry for dropping out of this topic, but I didn't have any time to play around some more. 

In my case, the USB stick was the bottleneck after all (tkaiser won't like this, but the random write test of bonnie did indeed show that is was very slow on those kind of writes), and an SSD in a USB enclosure did the trick. 

 

I have wasted enough time on this project, and since my requirements are met, I can't be bothered to do any more testing. Thank you for all the help though, especially you, tkaiser!

I'll probably have a go at the new tool you've implemented though 

[Best budget device as torrent box?]

 

Your application does random writes in small chunks and you try to test/understand the behaviour by testing something completely different: writing large sequential (non random!) chunks of data. That can't work.

Is it? 

 

 

• cache-size-mb: Size (default = 4), in megabytes, to allocate for Transmission's memory cache. The cache is used to help batch disk IO together, so increasing the cache size can be used to reduce the number of disk reads and writes. Default is 2 if configured with --enable-lightweight.

   

Or does this not matter and just means it collects x MB of random writes and starts writing them at that point?

 

I tried rTorrent, and on first sight, it seemed to perform better. I'll install a webgui tonight so it's easier to keep track of it.

 

I have read up a bit about your active benchmarking, but it seemed relatively hard to set up and interpret the output. It was easier to just try with an SSD

 

[Best budget device as torrent box?]

I tried the SSD on a raspberry pi (2) too, and it seems that it was also the USB drive that was bottlenecking everything. I also averaged 4.5MB/s on the raspberry.

I am having a real hard time comprehending why the USB stick is such a bottleneck. 

I tried writing a 15.5GB file (8gb ram in the system) to it in Windows (formatted as NTFS), which took 9min 29s. Or nearly 30 MB/s. The stick was directly unplugged after the copy was done, 

To verify the copy was indeed successful, I calculated a hash from the source file and the file on the stick.

 

So why, even with a big cache, is the performance so bad with transmission? 15 seconds to download 60MB, 2-3 seconds to write it to the stick. That is if it's sequential. Must be missing something :/

It's a Kingston DT Rubber 64GB by the way, first generation.

[Best budget device as torrent box?]

Which image / kernel do you have installed

uname -a

 

Have you stopped transmission and set the chache to 12MB and restarted?

Linux orangepipc 3.4.110-sun8i #18 SMP PREEMPT Tue Mar 8 20:03:32 CET 2016 armv7l GNU/Linux

I stopped transmission and set the cache to 64MB (plenty of ram,250 only 100-150 MB was used) and then started again. The writing to usb is the problem.

If I set the cache to 800MB, it goes fast until the ram is full and then hangs (average speed about 4MB/s or so). 1 core is on 100%, one on 46, and 2 on 10-15%.

It's the whole device that hangs. Starting a new ssh session hangs, logging on on the local console hangs, htop doesn't do anything anymore. It's freezed for 5 minutes now or so.

Pretty much the same problem as on the raspberry. I'm gonna try with an SSD in a docking station now

 

EDIT: It does seem to be the USB drive. With the SSD in a dock, I get nearly 5MB/s measured over 10 minutes. If someone could help me figure out why there's such a big difference, so I know what to check for when buying a USB drive, that would be great!

[Best budget device as torrent box?]

Wget at work got 7,03 MB/s from the same site. Pretty sure network is not the issue

The usb-drive is formatted in ext4.

I am not sure how to check the disk access pattern of transmission? 

How should htop be sorted to show the relevant information?

 

I have a Kingston DataTraveler Workspace (licensed WinToGo stick, 150 euro or something like that for 64GB). Waiting for some more instructions, I'll give that a go. At least I'll be sure it's not the stick then.

 

I also tried setting vm.swappiness=0 and vm.min_free_kbytes=0 in /ect/sysctl.conf (someone mentioned it fixed the kswapped issue for him), rebooted and tried again, but the problem was the same. 

 

I am not that familiar with Linux and all the command line tools, as you might have noticed

[Best budget device as torrent box?]

Made an account

Did some benchmarking!

wget --output-document=/dev/null http://speedtest.wdc01.softlayer.com/downloads/test500.zip

Averaged 2.23 MB/s, pretty much the max of my home connection. Will try at work tomorrow (got 350mbps down on speedtest.net there)

 

dd:

orangepi@orangepipc:~$ time sh -c "dd oflag=direct if=/dev/zero of=/media/usb/tmp bs=4K count=10000 && sync"
10000+0 records in
10000+0 records out
40960000 bytes (41 MB) copied, 26.2403 s, 1.6 MB/s

real    0m28.506s
user    0m0.000s
sys     0m0.950s
orangepi@orangepipc:~$ time sh -c "dd oflag=direct if=/dev/zero of=/media/usb/tmp bs=1M count=100 && sync"
100+0 records in
100+0 records out
104857600 bytes (105 MB) copied, 5.26363 s, 19.9 MB/s

real    0m5.337s
user    0m0.000s
sys     0m0.170s

I did longer runs first, but my pc crashed when I was posting the result. Speeds were the same.

 

Bonnie++:

Version  1.97       ------Sequential Output------ --Sequential Input- --Random-
Concurrency   1     -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP  /sec %CP
orangepipc       2G   112  98 18230  12 12774   8   540  99 49408  12  96.2   3
Latency             90441us    1195ms    1196ms   17282us   10268us    1188ms
Version  1.97       ------Sequential Create------ --------Random Create--------
orangepipc          -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
              files  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP  /sec %CP
                 16  2664  18 +++++ +++ 11275  59  9487  63 +++++ +++  7905  42
Latency               755us    1947us    2037us     822us     135us    1733us
1.97,1.97,orangepipc,1,1458080683,2G,,112,98,18230,12,12774,8,540,99,49408,12,96.2,3,16,,,,,2664,18,+++++,+++,11275,59,9487,63,+++++,+++,7905,42,90441us,1195ms,1196ms,17282us,10268us,1188ms,755us,1947us,2037us,822us,135us,1733us