How to disable TRIM on SSDs in Ubuntu

Question

I have enabled TRIM by adding discard option in /etc/fstab but even after removing it the effect is not going. How to disable it?

Answer 1

In 14.04 there is an automativ weekly trim. You can disable it with:
sudo rm /etc/cron.weekly/fstrim
But I wouldn't recommend totally disabling TRIM, this will slow your drive down with time.

Answer 2

To check the status of TRIM timer

sudo systemctl status fstrim.timer

You would get something like this:

● fstrim.timer - Discard unused blocks once a week
     Loaded: loaded (/lib/systemd/system/fstrim.timer; enabled; vendor preset: enabled)
     Active: active (waiting) since Mon 2022-01-10 06:36:56 CET; 31min left
    Trigger: Mon 2022-01-17 00:00:00 CET; 6 days left
   Triggers: ● fstrim.service
       Docs: man:fstrim

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To disable the periodic TRIM (TRIM timer)

sudo systemctl disable fstrim.timer

To manually invoke TRIM (on all mounted FS)

sudo fstrim --all

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Further reading:

• fstrim man page #1
• fstrim man page #2
• Does SSD Trim actually increase the lifespan? (Quora)

Answer 3

Disabling trim is very important for legacy servers that pre-date SATA. SSD's can be fitted for power, reliability as well as some speed increase by means of an IDE to SATA bridge or converter. Or a DOM package plugged directly into the MB.

Some of these hang on TRIM. Random writes to the SSD are 3-4 times faster than UDMA so TRIM does not matter, it has time to write twice.

My approach is to comment out /etc/cron.weekly/fstrim (c. Utopic or Trusty LTS)

#!/bin/sh
# trim all mounted file systems which support it
# /sbin/fstrim --all || true

Of course this will also affect SATA SSD's on a PCI expansion card, but that's something else.