# Why is my snapshot's size different from reported disk usage?

Snapshots of Droplets are a best estimate based on the disk usage. Snapshots of volumes operate at the block storage level, so the snapshot size may not match what the filesystem reports.

The filesystem may not immediately mark blocks as unused, which makes the block storage system include them in snapshots even though they don’t contain data.

You can trim or discard unused blocks to make volume snapshots smaller and therefore less expensive. [Configuring periodic `fstrim`](https://www.digitalocean.com/community/tutorials/how-to-configure-periodic-trim-for-ssd-storage-on-linux-servers). You can also mount volumes with the discard option, which helps ensure that the block storage system knows which blocks are used and which are not.

## Related Topics

[Can I restore individual files or directories from a snapshot or a backup?](https://docs.digitalocean.com/support/can-i-restore-individual-files-or-directories-from-a-snapshot-or-a-backup/index.html.md): The only way to restore files from an image is to recreate a Droplet or volume from the image and copy the flies from there.

[Can I downsize a Droplet using a snapshot?](https://docs.digitalocean.com/support/can-i-downsize-a-droplet-using-a-snapshot/index.html.md): You cannot downsize a Droplet from a snapshot. Data is not always stored sequentially in memory, so reducing the size of a disk can result in data loss or corruption.

[How do I fix a "The resource you were accessing could not be found" error when restoring a Droplet from a snapshot?](https://docs.digitalocean.com/support/how-do-i-fix-a-the-resource-you-were-accessing-could-not-be-found-error-when-restoring-a-droplet-from-a-snapshot/index.html.md): This error happens when the Droplet you’re trying to restore no longer exists, so try creating a new Droplet from the snapshot instead.