hello friends, i currently have my nextcloud 25 in my proxmox in a lxc container with turkey-core with 3gb ram and 2 core and i have a 30mb internet connection and i can watch hd and 4k videos without problems over all internet thats why i thought my nextcloud ran smoothly and perfect, i put some screenshots here
the problem I see and I don’t know if it’s normal, is that when I send a link to a video that is stored on a disk that is connected to my nexcloud, the video is extremely lagin, cut off slowly and it’s a very bad experience, no It doesn’t matter if the video is short or long with good quality.
however, if I want to see any content or video up to 4k directly through the local network, it looks perfectly and without any lag, apparently the problem happens only when it opens the video in nextcloud over the internet
I would like to know if anyone has experienced this and how it can be resolved?
If your net and CPU seem fine, did you check the I/O performance?
The hard disk is a crucial factor when it comes to serve higher amounts of data.
And if I see your swap there, it seems that your machine is swapping happily and that might turn down the hard drives or SSD’s I/O performance.
Maybe you check with something like “iotop” or “glances” what the disk does?
I also have a bit more memory consumption when the NC cron job fires off since 25 and my Pi4 is in a wild swapping mode which then again kills a lot of the systems overall performance.
You still seem to have enough memory left, so you might consider changing the systems swappiness with adding a line “vm.swappiness=5” and “vm.vfs_cache_pressure=40” to your
/etc/sysctl.conf and reboot. The “swappiness” is preventing that the system swaps as it would in normal behaviour, but a lot less. Usually, you cannot break things here and you can always delete the line out of the config again. I would give it a try 
Edit: Also memcached and redis and a good configuration of your mysql/mariadb would be advised, which takes off some more I/O performance from the disk if needed.
