Discard / Trim for SSD disks

[Wouter Samaey]

I noticed that the `Discard` (sometimes called `Trim`) option is turned off by default.
This is needed to keep backups smaller as disk space can be reclaimed on SSD disks.

I'd like to understand:

- Why is the Discard option disabled by default?
- Can't Proxmox auto-detect if the underlying disk is an SDD? We could have an "auto" mode so we are not bothered with this? We've wasted lots of time looking into this
- Are there any risks?

 

[t.lamprecht]

Why is the Discard option disabled by default?

Not all disks are SSDs and all SSD controller (mostly some cheap "off brand" or older ones) support the discard protocol correctly.
This was more an issue when this options was introduced first some years ago, though.

Can't Proxmox auto-detect if the underlying disk is an SDD? We could have an "auto" mode so we are not bothered with this? We've wasted lots of time looking into this

Something like this would be nice to have in the future. It'd be great if you could open an enhancement request over at our bug and feature tracking system: https://bugzilla.proxmox.com/

 

[Wouter Samaey]

I've created the feature request here: https://bugzilla.proxmox.com/show_bug.cgi?id=2729