Sometimes its the LEAST expected thing (that one this article does not cover). Some time ago I had some really cheap SATA 2.5 SSD 256 GB in my laptop. If gene

Sometimes its the LEAST expected thing (that one this article does not cover). Some time ago I had some really cheap SATA 2.5 SSD 256 GB in my laptop. If generally worked well - system (FreeBSD) was responsive but ... when I deleted large file (like 1GB+ size) then the system almost FROZE ... until file is deleted. After some investigation with Allan Jude (thanks again) we came to the conclusion that a single TRIM operation (for delete) take about 500ms (half a second) ... By default ZFS on FreeBSD uses up to 64 TRIM operations PER SECOND (the vfs.zfs.vdev.trim_max_active setting) - so the SSD was literally DoS with TRIM operation and it crippled it to its knees. After switching this option from 64 to 1 it solved all the problems and everything was smooth and fast again. Details below. % grep -A 1 -i trim /etc/sysctl.conf # ZFS DELETE FUCKUP TRIM # vfs.zfs.vdev.trim_max_active: 64 -> 1 vfs.zfs.vdev.trim_max_active=1 Hope that will help someone. Regards, vermaden