[SOLVED] whether should I turn on “discard” option for ext4 in LVM ...

If the filesystem is mounted with discard, then deleting files will automatically cause the TRIM command to be issued. This often has a negative performance ...

It seems performance is better with periodic trim IF you have have an over-provisioned or no where near full SSD.

The discard option performs TRIM immediately when a file is deleted, and there is some performance hit involved.

This testing shows that mounting an Ext4 file system with the discard mount option dramatically impacts file removal operations. The default ...

The FITRIM message is better than TRIM for performance on SSD disk. This support comes since 2.6.37 - so online discard is replaced by ...

I have run this particular test on ext4 filesystem with -o nodiscard and -o discard mount options 10x with each mount option, then I have computed average ...

Discard can effect performance if it decides to trim during disk activity. Discard=async tries to delay trim until another later time, so ...

From what I have read, discard on it's own will sometimes try to trim when it is writing - affecting performance. discard=async will wait until ...

With “discard” on, deleting a big bunch of small files is 64 times slower on my SSD. For those ~40 seconds any I/O is really slow.

It will slow down your drive as TRIM is applied constantly. A better option would be to use `fstrim` periodically -- I use it with a systemd timer.