Raspberry Pi card "full" when it's not

Hi all,

I've been running a Pi as an embedded controller for a time-lock safe for several years without issue. It's programmed to open up twice a week on a Tuesday and a Friday and just recently I wanted to change the Tuesday for a Wednesday, which with this script is just a case of changing a '2' for a '3' on a single line of code, so no overall increase in space required (this is on a 4Gb SD card). However, when I try to save the change, I get an error message saying the card is full and I need to delete some files to make space! I'm pretty damn sure there's plenty of space on the card in reality and what I'm trying to do doesn't even require a single bit of extra space anyway, so what's going on here? I'm sure I've had this issue before many years ago but Linux is so reliable I so rarely need to fix anything so forget what I previously did.
Can some kind soul tell me what I'm doing wrong? Thanks.

did you check the inodes? df -i

Originally Posted by pan64 did you check the inodes? df -i

Sorry for the delay; I'm just reading up on inodes (never heard of 'em before). This may take a while longer.....

If the Pi has been running for several years its possible the card has worn out.

If so, I would create a backup if you do not have one ASAP

Logs ?. Let's see

df -hT

Originally Posted by michaelk If the Pi has been running for several years its possible the card has worn out. If so, I would create a backup if you do not have one ASAP

My brain will wear out before the card, since it's write-protected in this application. In fact, maybe that's what's already happened.
I need to sleep on this inode business. Hopefully it'll make more sense in the morning.

Originally Posted by Completely Clueless I'm pretty damn sure there's plenty of space on the card in reality

How sure? Have you checked?
Provide the output requested in post #5.
Use code tags for that (see my signature).

Originally Posted by ondoho How sure? Have you checked? Provide the output requested in post #5. Use code tags for that (see my signature).

Sigh.. I only wish I could. Unfortunately a colleague of mine has slammed the door shut and it's latched again. Now I won't be able to re-open it to get to the Pi and the card until Tuesday. Thanks for trying to help, everyone. I'll have to re-post in a few days' time with the outcomes to your various suggestions.

How have you write protected it? Are you sure it isn't just write protected across the board?

Originally Posted by Roken How have you write protected it? Are you sure it isn't just write protected across the board?

There's a tiny switch on the SD card itself; that's what I used.

Originally Posted by Completely Clueless There's a tiny switch on the SD card itself; that's what I used.

OK, and have you unlocked it to write the file?

Sorry for the delay. Yes, the 'lock' switch on the card has been disabled to make it writable, but it still won't save. And the error message specifically says there's no space on the card, too.

Here's the outputs I'm seeing from the two suggested commands:

bro@bro-laptop ~/Desktop $ df -hT
Filesystem     Type      Size  Used Avail Use% Mounted on
udev           devtmpfs  2.9G  4.0K  2.9G   1% /dev
tmpfs          tmpfs     581M  1.4M  580M   1% /run
/dev/sda6      ext4      123G   65G   52G  56% /
none           tmpfs     4.0K     0  4.0K   0% /sys/fs/cgroup
none           tmpfs     5.0M     0  5.0M   0% /run/lock
none           tmpfs     2.9G   37M  2.9G   2% /run/shm
none           tmpfs     100M   36K  100M   1% /run/user
/dev/sdb2      ext4      1.7G  1.6G     0 100% /media/bro/b7b5ddff-ddb4-48dd-84d2-dd47bf00564a
/dev/sdb1      vfat       56M   19M   38M  34% /media/bro/3312-932F

bro@bro-laptop ~/Desktop $ df -i
Filesystem      Inodes  IUsed   IFree IUse% Mounted on
udev            739446    542  738904    1% /dev
tmpfs           743494    599  742895    1% /run
/dev/sda6      8167424 412295 7755129    6% /
none            743494      2  743492    1% /sys/fs/cgroup
none            743494      1  743493    1% /run/lock
none            743494     63  743431    1% /run/shm
none            743494     21  743473    1% /run/user
/dev/sdb2       114688  68577   46111   60% /media/bro/b7b5ddff-ddb4-48dd-84d2-dd47bf00564a
/dev/sdb1            0      0       0     - /media/bro/3312-932F
bro@bro-laptop ~/Desktop $

The card is mounted on dev/sdb for the avoidance of any doubt.
I'm going to have to return this card to the controller very shortly so if there are any further suggestions requiring access, I may have to defer trying them until Friday when the safe will be open again.
Thanks.

Filesystem     Type      Size  Used Avail Use% Mounted on
/dev/sdb2      ext4      1.7G  1.6G   0   100% /media/bro/b7b5ddff-ddb4-48dd-84d2-dd47bf00564a

The output shows the partition is full. By default ext4 does reserver 5% for root use. With a 1.6G partition reserved space is only 85MBs.

You need to delete some stuff.

Originally Posted by michaelk Filesystem Type Size Used Avail Use% Mounted on /dev/sdb2 ext4 1.7G 1.6G 0 100% /media/bro/b7b5ddff-ddb4-48dd-84d2-dd47bf00564a The output shows the partition is full. By default ext4 does reserver 5% for root use. With a 1.6G partition reserved space is only 85MBs. You need to delete some stuff.

OK, well let's try that, then. How little can I get away with deleting and from which of sdb1 or sdb2 should it come off?

You need to delete to get below 95% and would say at least 100Mb.

sdb2..