Free space is wrongly calculated for USB disk

[MaxWinterstein]

Thanks for that script, might save me a lot of work when getting my broken btrfs up again 👍

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When using a USB disk as a backup target, the free space is calculated wrongly.

sudo -s $PWD/syno_app_mover.sh
Synology_app_mover v3.0.50
DS923+ DSM 7.2.1-69057-5

Running from: /volumeUSB1/usbshare/disaster_recovery/Synology_app_mover-3.0.50/syno_app_mover.sh

1) Move
2) Backup
3) Restore
Select the mode: 2
You selected Backup

Backup path is: /volumeUSB1/usbshare/disaster_recovery/

Do you want to backup All packages? [y/n]
n
[Installed package list]
 1) /volume1  Active Backup for Business
 2) /volume1  Active Backup for Google Workspace
 3) /volume1  Active Backup for Microsoft 365
 4) /volume1  Apache HTTP Server 2.4
 5) /volume1  cloudflared
 6) /volume1  Cloud Sync
 7) /volume1  Container Manager
 8) /volume1  DNS Server
 9) /volume1  Document Viewer
10) /volume1  Hyper Backup
11) /volume1  OctoPrint
12) /volume1  Storage Analyzer
13) /volume1  Synology Application Service
14) /volume1  Synology Photos
15) /volume1  Text Editor
16) /volume1  Web Station
Select the package to backup: 7
You selected Container Manager in /volume1

Destination volume is /volumeUSB1

Ready to Backup Container Manager to /volumeUSB1/usbshare/disaster_recovery/? [y/n]
y

du: cannot access '/volume1/@docker/containers/774f0a6b0838502a0c634ad0ebe6959cb5ce9ba1cfa83d6e2e9464268ae15841/log.db-journal': No such file or directory
vol_free_space called with /volumeUSB1
free is set to 6455240
WARNING Not enough space to backup /volume1/@docker to /volumeUSB1
Free: 6 GB  Needed: 191 GB (plus 50 GB buffer)

ERROR Not enough space on /volumeUSB1 to backup @docker!

the line vol_free_space called with /volumeUSB1 was added by me, but shows the issue.

As the USB volume is mounted within /volumeUSB1/usbshare the free space if / is returned.

df
Filesystem              1K-blocks       Used  Available Use% Mounted on
/dev/md0                  8191352    1617448    6455120  21% /
...
/dev/usb2p1            3844638928 1287314448 2557205696  34% /volumeUSB1/usbshare

[007revad]

Did you also add the free is set to 6455240 line?

I suspect the targetpath variable was empty so df processed / instead of the expected /volumeUSB1

Can you run this test script and confirm that it does not give the same error? All it does it check if there's enough space.
https://github.com/007revad/Synology_app_mover/blob/test/syno_app_mover_test.sh

I've found another bug while testing this. I tested with a USB thumb drive that only had 670MB free and the script said it had 6GB free.

I also notice you got another error:

du: cannot access '/volume1/@docker/containers/774f0 <snipped> 15841/log.db-journal': No such file or directory

That error is harmless, which is probably why you didn't mention it.

[MaxWinterstein]

Did you also add the free is set to 6455240 line?

yes

Can you run this test script and confirm that it does not give the same error? All it does it check if there's enough space.
https://github.com/007revad/Synology_app_mover/blob/test/syno_app_mover_test.sh

max@Synology:/volumeUSB1/usbshare/disaster_recovery/Synology_app_mover-3.0.50$ sudo bash syno_app_mover_test.sh
Password:

You selected Move
You selected Container Manager

debug: backup path: /volumeUSB1/usbshare/disaster_recovery/
debug: target volume: /volumeUSB1

(ditched some i/o errors here)

WARNING Not enough space to backup /volume1/@docker to /volumeUSB1
Free: 6 GB  Needed: 189 GB (plus 50 GB buffer)

ERROR Not enough space on /volumeUSB1 to backup @docker!

I also notice you got another error:

yes, my whole volume1 is dying currently. Somehow the btrfs is corrupted, starting without any reason at all.

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some more df for comparisment:

max@Synology:/volumeUSB1/usbshare/disaster_recovery/Synology_app_mover-3.0.50$ df /volumeUSB1
Filesystem     1K-blocks    Used Available Use% Mounted on
/dev/md0         8191352 1620456   6452112  21% /
max@Synology:/volumeUSB1/usbshare/disaster_recovery/Synology_app_mover-3.0.50$ df /volumeUSB1/
Filesystem     1K-blocks    Used Available Use% Mounted on
/dev/md0         8191352 1620472   6452096  21% /
max@Synology:/volumeUSB1/usbshare/disaster_recovery/Synology_app_mover-3.0.50$ df /volumeUSB1/usbshare
Filesystem      1K-blocks       Used  Available Use% Mounted on
/dev/usb2p1    3844638928 1522498428 2322021716  40% /volumeUSB1/usbshare
max@Synology:/volumeUSB1/usbshare/disaster_recovery/Synology_app_mover-3.0.50$ df /
Filesystem     1K-blocks    Used Available Use% Mounted on
/dev/md0         8191352 1620524   6452044  21% /

[007revad]

I see the problem now. For USB drives the mount point is /volumeUSB1/usbshare and not /volumeUSB1

This new version should work now https://github.com/007revad/Synology_app_mover/releases/tag/v3.0.51

[MaxWinterstein]

Works fine, thanks!