I have a volume in Longhorn on Harvester which is getting a bit big. I would like to trim the filesystem on it, is that feasibly? I'm getting an error when I try with the LH UI

Hi Alex, you may have better luck finding an answer in the #CC2UQM49Y channel. That being said Harvester usually creates volumes in Block mode, not Filesystem mode. This means that the filesystem on the volume, and subsequently also the trimming operations, are wholly within the responsibility of the guest VM's operating system. Check your guest VM's operating system configuration to see if it already has a mechanism for trimming the filesystem enabled. Note that not all filesystems support trimming and your guest OS may have multiple different ways to configure it. On Linux based guest VMs if a volume is mounted with the option

discard

, then trim commands are automatically issued to the block device - if the filesystem supports it. But there are alternative methods as well. Sometimes the OS runs

fstrim

or

blkdiscard

on a cron-timer, ext3/ext4 filesystems may have trimming enabled with tunable parameters via

tune2fs

and encrypted filesystems with LUKS need to be explicitly set up to support trimming at creation time.

Ohhhhhhh right! I never realised it was block rather than filesystem. Thank you!