Transmission add-on crashing on ReadyNas Duo

[Dr_Strangelove]

I'm having stability issues with Transmission on my Duo. The web GUI loses connection with the add-on and the green little indicator in the Duo's web GUI goes gray. I interpret this as the process crashed or stopped in some way. I can restart the Transmission but as soon as I try to do something, e.g., deleting a torrent, Transmission crashes again. I've enabled DHT but shouldn't the Duo have enough power to run Transmission anyway? Or can't I expect this add-on to run on this relatively weak system? I haven't upgraded the RAM either.

[JarnoG]

The Duo has enough resources to run Transmission, but you have to limit the settings a bit. To change these settings, you will have to disable Transmission, then open this file:
\\IpOfNAS\addons-config\Transmission\transmission-daemon\settings.json
Change the following settings:
"cache-size-mb" should be a few MB (~2 or so)
"peer-limit-global" should be around 50
"peer-limit-per-torrent" should be around 5

Then start Transmission again and it should work better.

[Dr_Strangelove]

Thanks JarnoG. Seems to work fine so far.

[frantyk]

Thanks will try these settings also.
I have already turned off DHT too.

[perfectdark]

"cache-size-mb" should be a few MB (~2 or so)

is this cache meaning 2MB? not sure what the "~" mean?

i set mine up as follows

"cache-size-mb" 2mb
"peer-limit-global" 50
"peer-limit-per-torrent" 5

and transmission responds faster now but the torrent downloads are slow

[Sushiboy]

i set mine up as follows

"cache-size-mb" 2mb
"peer-limit-global" 50
"peer-limit-per-torrent" 5

and transmission responds faster now but the torrent downloads are slow

That's bad news for me, as those kind of peer limits are too constraining. It looks like I'm stuck with 2.22, which I've been using for a couple years, as it's the latest version I seem to be able to run on my Duo that's stable. Anything after that routinely disconnects on me.

The standard settings (and the ones I use) for 2.22 are:
"cache-size-mb" 2
"peer-limit-global" 240
"peer-limit-per-torrent" 60

For 2.42 it's:
"cache-size-mb" 200
"peer-limit-global" 240
"peer-limit-per-torrent" 60
but even setting the cache to 2 doesn't stop 2.42 from disconnecting on me.

I hope an update is in the works which fixes these stability problems.

[JarnoG]

for the "cache-size-mb", you should set it to 2, not 2mb, but apparently, Transmission doesn't mind much if it's running. The "~" means "about", you can try increasing it to 4 or maybe even 8 to increase the download speed. A higher number means less writes to the disk, which results in faster download. But it also means that it will be short on ram memory quickly and start swapping to the disk, which will result in slower downloads again and might result in Transmission crashing.

The "cache-size-mb" is the maximum cache used per peer, so if you are downloading from 50 peers, and it is set to 4MB, you will use up 200MB of ram for caching. The Duo only has 256MB, so if it has much other stuff running, the memory will be full quickly. If you set the cache size to 8MB, Transmission will want to use 400MB of ram, which the Duo doesn't have, so the swap will be used. If 240 peers with 2MB each worked in 2.22 and it doesn't work in 2.42, then apparently, there's a problem with running Transmission while swapping a lot.

[Sushiboy]

The Duo only has 256MB, so if it has much other stuff running, the memory will be full quickly. If you set the cache size to 8MB, Transmission will want to use 400MB of ram, which the Duo doesn't have, so the swap will be used. If 240 peers with 2MB each worked in 2.22 and it doesn't work in 2.42, then apparently, there's a problem with running Transmission while swapping a lot.

Thanks for this explanation. But I'm running 1GB of memory, and it still disconnects with 2.31 and 2.42.

I found some interesting comments at https://forum.transmissionbt.com/viewtopic.php?f=2&t=12746 regarding settings.json settings in 2.42. Might there be some applicability to the problems many of us have experienced with it?

• "max-peers-global": 200, invalid for 2.42--remove
• "open-file-limit": 10, invalid for 2.42--remove
• "peer-limit-global": 100,
"peer-limit-per-torrent": 20, Reduce both by 50%.
• "upload-limit": 100,
"upload-limit-enabled": 0, Both are invalid for 2.42--remove
• "utp-enabled": true, Try setting to false. Daemon must be quit before making changes.

[JarnoG]

If I recall correctly, I read on the transmission forums somewhere that the "max-peers-global" and "open-file-limit" haven't been used since version 1.4 or so. As far as I know, they are ignored and will not cause problems. The "upload-limit-*" have been replaced by the "alt-speed-*" and "speed-limit-*" in version 1.5. (see the link given in the topic your link to)

It also says that "open-file-limit" is used in version 2.31 and older, so, if 2.31 crashes for you too, that might not be the problem. You can try to reduce the queuing and peer limits to see if this works.

[Sushiboy]

If I recall correctly, I read on the transmission forums somewhere that the "max-peers-global" and "open-file-limit" haven't been used since version 1.4 or so. As far as I know, they are ignored and will not cause problems. The "upload-limit-*" have been replaced by the "alt-speed-*" and "speed-limit-*" in version 1.5. (see the link given in the topic your link to)

It also says that "open-file-limit" is used in version 2.31 and older, so, if 2.31 crashes for you too, that might not be the problem. You can try to reduce the queuing and peer limits to see if this works.

Thanks for the clarification. Here's what the Transmission forum says https://trac.transmissionbt.com/wiki/EditConfigFiles

2.31 (and older)
open-file-limit: Number (default = 32)

1.4x (and older)
Peers
max-peers-global: Number (default = 240)
max-peers-per-torrent: Number (default = 60)

This is all way too confusing for a simple plug-and-play Mac guy like me. Why on earth can't we have a settings.json file installed that's actually compatible with the version of Transmission being installed? Also, why can't it be compatible with the specific ReadyNAS model it's being installed on? Why all this confusion?

What I still don't understand is why do my settings work fine in 2.22, but the same settings fail in 2.31 and 2.42? e.g.
"cache-size-mb": 2,
"peer-limit-global": 240,
"peer-limit-per-torrent": 60,

It amazes me how many people are having the same basic Transmission UI disconnect problem and (from what I've seen) no one has yet to identify the root cause and how to quantitatively troubleshoot and fix it. So far all I've seen is everyone taking this shot in the dark approach of reduce this and that setting. Oh, that didn't work? Well lower them some more. Still didn't work? Well, try reducing something else and see if that works. It shouldn't be so mystical and abstract.

[JarnoG]

Since 2.22, quite a few new features are added to Transmission. Each feature requires more from your NAS, which means that each feature might be one to much. Most new features can be disabled, but since Transmission includes those features to be used, they turn them on by default. The old parameters are still in the settings.json file to make sure nothing unexpected happens and that a downgrade to an older version goes smoothly.

The Duo is a machine that has limited resources because it is not intended to be a high performance server (that is what the Pro series, and to a lesser extend, the Ultra series are for), but a simple solution to host files on a home network. This means that it might not be able to cope with all the new features and other resource-eating-functionalities without some tweaking. What tweaks work for you depends on the demands you put on them. I don't know why you require a high peer limit, but that means that you have to squeeze other features.

[Sushiboy]

Thanks JarnoG. I appreciate your patience with me. Your explanation makes a lot of sense.

I attempted once again to install 2.42 with the following settings:
"cache-size-mb": 2,
"peer-limit-global": 100,
"peer-limit-per-torrent": 10,

So far so good (keeping my fingers crossed).

As far as thinking I needed the higher peer limits, I can probably get by without it.

Thanks again for all your help. It's much appreciated.

[Sushiboy]

I was successful in adding back all my previous torrents. Smooth sailing. And then... After adding just one more newly created torrent, the dreaded

I then disable Transmission, changed to the following settings:
"peer-limit-global": 50,
"peer-limit-per-torrent": 5,

Still no go. I then deleted from the queue all my torrents and attempted to add just the one newly created torrent again. Within seconds the dreaded message appeared again! To say the least this is maddening. I have never ever experienced anything like this with 2.22.

Any final suggestions?

[JarnoG]

To me it seems that you've got one torrent that gives the problem, while all the others work just fine. When you're in the webGUI of Transmission, go to the settings window and disable PEX, DHT and LPD on the Peers tab and UTP on the Network tab. Those are extra services that Transmission uses to improve downloading. It might be that the torrent uses one of these services which then causes Transmission to crash.

[Sushiboy]

I did have PEX enabled. Nothing else. I've disabled PEX and Removed all torrents. Then I opened two small torrents. They verified okay and everything looked fine. Then I created a third 1.5GB torrent and attempted to open it. The dreaded Connection Failed message appeared almost immediately.

UPDATE: The problem does indeed appear to be with one particular offending torrent, or at least that's where I'm at now in my troubleshooting.

I create my torrents with Transmission for Mac. The weird thing is I can create it and even open it in Transmission-Mac, and it verifies fine. However, after I reinstalled Transmission 2.22 on my Duo I noticed that it wouldn't verify to any more than 93.7%. What I've narrowed it down to are the file names contained within the torrent. Some of them are accented characters. The Duo handles that just fine. In fact, I'd originally used Transmission on the Duo to download the same files from another torrent site. I wanted to reshare them to a different (private) torrent site, so I took the same exact unmodified files and created a new torrent to upload to the new site. That's where the problems began. Apparently Transmission-Duo has no trouble downloading torrents where the included files have accented characters. But trying to create a new torrent with the same files and have Transmission-Duo verify them will choke the verification process on the accented character names.

What I don't understand is why 2.22 at least functions and shows that the file won't fully verify apparently due to the file names (changing the file names to un-accented characters resolves that problem). However, 2.42 chokes and dies within seconds of opening the torrent file and commencing the verify process.