Written 28 Aug 2026. This is a how-to, not a product card. Buy links are not tagged yet.

When copies fail but free space looks fine

Before you buy a bigger drive or a NAS, check leftover-box file slots with df -i when copies fail but free space looks fine.

Photos stop copying. The leftover box says the disk is full. Then see if the leftover box still has room shows plenty of gigabytes left. That is not a broken meter. The leftover box also has a limited count of file slots. When those slots are used up, new files fail even if there are gigabytes free. You are not buying a NAS for this look.

Skip until SSH works

If you cannot log in from the couch, stop. That is SSH from the couch. This note assumes you can type commands on the leftover box from the couch.

What this is

A file slot is the leftover box's name for each file and folder. Linux people call that an inode. You do not need the word. You need the check. df -h is gigabytes. df -i is file slots. This is not the same note as see which leftover-box folders are eating the disk (that is which folders ate the gigabytes) or clear old leftover-box logs when the disk is tight (that is diary size). You are only asking whether the file-slot column is full.

Ask for the file slots

SSH in from the couch, then ask:

df -i

Point at the line for the leftover-box root, usually /. Read IUse% (or the Use% column on some boxes). Under about 80% is normal. Near 100% means the leftover box ran out of file slots, not gigabytes. That is why a copy can fail while df -h still looks fine.

Optional one-line focus, if the full table is noisy:

df -i /

If the file slots are nearly full

Do not format the disk. Do not buy a drive tonight. First see which folders are busy: see which leftover-box folders are eating the disk. Lots of tiny files in one folder (old logs, leftover package lists, a leftover person's Downloads) eat file slots fast. Safe cleanups that often help:

• clear old package downloads when the leftover disk is tight
• clear old leftover-box logs when the disk is tight

If IUse% is low and copies still fail, go back to gigabytes: see if the leftover box still has room. Skip a monitoring box for this look.

What next

Gigabyte room stays see if the leftover box still has room. Folder sizes stay see which leftover-box folders are eating the disk. How big the leftover disk already is stays see how big the leftover box disk already is. A second copy is a backup of the leftover-box folder. Skip a new 4TB drive this weekend.

Skip

• Skip this note if SSH from the couch does not work yet. That is SSH from the couch.
• Skip buying a bigger drive or a NAS because one copy failed once.
• Skip formatting the leftover disk tonight.
• Skip a monitoring box for this look.
• Skip opening SSH to the internet.