# Trim Vs. Discard

## RayDude

I just found out about the fstrim command. Is this documented somewhere?

I'm mounting my SSDs with discard. I had read years ago that was the way to do it.

But I saw a thread in /r/linux on reddit about fstrim, found out that discard comes with a performance hit and ran fstrim on the "discard" mounted file systems and it trimmed a lot of disk space...

If the FS was mounted with discard, why would it find stuff to trim?

Can someone point me to the way this is supposed to be done?

Thanks.

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## mike155

Please look here: https://wiki.archlinux.org/index.php/Solid_State_Drive

They discuss pros and cons of continuous trim vs. periodic trim.

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## RayDude

Thanks.

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