Transmission

Hi. I’m having some problems with Transmission (v.3.00) on my Raspberry Pi 3 B (I’m using arm64 DietPi v7.8.2, prev version - the same result). The web-interface hangs when I use external USB drive to download and when I download a large file (larger file - easier to see the problem). The web interface is generally not available until preallocation is complete. I’ve tried using the preallocation = 0 and 1 parameters - the same result. When the download is stopped, the web interface works fine. CPU load is less 10% (except ntfs of course). The torrent file file is downloaded normally, the problem is only in the web interface. I tried USB HDD, USB stick. Tried exfat, ext4, ntfs. BTW, I saw almost the same behavior with Raspbian OS. From other side, Transmission 3.00 (bb6b5a062e) on my router (MT7620, 128 MB RAM) works without that problem.

Stage 2.
I tried to rebuild transmission with and without ‘–enable-lightweight’ - the result is the same.
strace for transmission-daemon looks like:
fsync(2) = -1 EINVAL (Invalid argument)
epoll_pwait(5, [], 32, 1000, NULL, 8 ) = 0
fsync(2) = -1 EINVAL (Invalid argument)
epoll_pwait(5, [], 32, 996, NULL, 8 ) = 0
fsync(2) = -1 EINVAL (Invalid argument)
epoll_pwait(5, [], 32, 992, NULL, 8 ) = 0
fsync(2) = -1 EINVAL (Invalid argument)
epoll_pwait(5, [], 32, 996, NULL, 8 ) = 0
fsync(2) = -1 EINVAL (Invalid argument)
epoll_pwait(5, [], 32, 996, NULL, 8 ) = 0
fsync(2) = -1 EINVAL (Invalid argument)
epoll_pwait(5, [], 32, 996, NULL, 8 ) = 0
And the web interface still freezes… :frowning:
The problem appears with USB storage only.

Stage 3.
Related to:
https://github.com/transmission/transmission/issues/553
https://github.com/transmission/transmission/issues/1314

looks like your system is quite busy doing heavy I/O operations. You could try using tools like sar, iostat or iotop to get some inside.

https://unix.stackexchange.com/questions/55212/how-can-i-monitor-disk-io