I just tried to open new terminal window and this error message displayed:
Failed to open PTY: No space left on device
It seems I can't open terminal window anymore unless closing existing one (or reboot). I don't have any other problem in my system.
Debian Buster (xfce4) Linux debian 4.19.0-18-amd64 #1 SMP Debian 4.19.208-1 (2021-09-29) x86_64 GNU/Linux
Filesystem Size Used Avail Use% Mounted on udev 3.9G 0 3.9G 0% /dev tmpfs 786M 9.5M 776M 2% /run /dev/sda4 320G 244G 62G 80% / tmpfs 3.9G 315M 3.6G 9% /dev/shm tmpfs 5.0M 4.0K 5.0M 1% /run/lock tmpfs 3.9G 0 3.9G 0% /sys/fs/cgroup tmpfs 786M 32K 786M 1% /run/user/1000
Filesystem Inodes IUsed IFree IUse% Mounted on udev 978K 455 978K 1% /dev tmpfs 982K 872 981K 1% /run /dev/sda4 21M 7.2M 14M 36% / tmpfs 982K 394 982K 1% /dev/shm tmpfs 982K 5 982K 1% /run/lock tmpfs 982K 17 982K 1% /sys/fs/cgroup tmpfs 982K 34 982K 1% /run/user/1000
Pretty sure there isn't any problem with storage or inodes count. I have closed all opened programs, after that I can open a few more terminal window, but still getting the error message.