Pihole throwing Disk almost full errors but Ubuntu shows plenty of disk space

The issue I am facing:
Pi-Hole has been showing daily Pihole and Pihole-FTL disk almost full errors (saying 98% full) and I can't delete these error messages in pi-hole diagnosis even though Ubuntu shows plenty of disk space.

Details about my system:
Ubuntu 22.04 on linux/celeron amd64 system. 8 gb memory. 2 tb ssd.

*** [ DIAGNOSING ]: Pi-hole diagnosis messages
   count   last timestamp       type                  message                                                       blob1                 blob2                 blob3                 blob4                 blob5               
   ------  -------------------  --------------------  ------------------------------------------------------------  --------------------  --------------------  --------------------  --------------------  --------------------
   1       2023-02-21 15:57:14  DISK                  /etc/pihole/pihole-FTL.db                                     98                    /etc/pihole: 1.9TB u                                                                  
                                                                                                                                          sed, 2.0TB total                                                                      
   1       2023-02-21 15:57:14  DISK                  /var/log/pihole/FTL.log                                       98      

What I have changed since installing Pi-hole:
Pihole with DOH via cloudflared, keep alive failover installed, this is the primary pihole.

log = https://tricorder.pi-hole.net/tl8gYwS4/

df command (I can't cut and paste it from my rdp window) shows 76% full on ssd drive...

The commands listed here will show the directories with the most space used. In that thread it turned out to be /var/log/pihole/pihole.log, and log rotation not working, which was eating the space. Worth checking in case it's the same for you.

You can disable the disk space checks or change the warning threshold:


They can but that's not advisable in this case.

   [2023-02-21 00:05:19.617 1278/T1320] WARNING: Disk shortage (/etc/pihole/pihole-FTL.db) ahead: 99% is used (/etc/pihole: 2.0TB used, 2.0TB total)
   [2023-02-21 00:05:20.618 1278/T1320] add_message(type=8, message=/etc/pihole/pihole-FTL.db) - SQL error step DELETE: database is locked
   [2023-02-21 00:05:20.618 1278/T1320] Error while trying to close database: database is locked
   [2023-02-21 00:05:20.618 1278/T1320] WARNING: Disk shortage (/var/log/pihole/FTL.log) ahead: 99% is used (/var/log/pihole: 2.0TB used, 2.0TB total)
   [2023-02-21 00:05:21.619 1278/T1320] add_message(type=8, message=/var/log/pihole/FTL.log) - SQL error step DELETE: database is locked
   [2023-02-21 00:05:21.619 1278/T1320] Error while trying to close database: database is locked
   [2023-02-21 00:06:00.007 1278/T1319] Encountered error while trying to store client in long-term database

df does show that the NVMe drive has space but that drive size doesn't match up with what we are seeing.

*** [ DIAGNOSING ]: Disk usage
   Filesystem      Size  Used Avail Use% Mounted on
   tmpfs           773M  6.9M  767M   1% /run
   /dev/nvme0n1p2  1.8T  1.3T  485G  73% /
   tmpfs           3.8G  2.2M  3.8G   1% /dev/shm
   tmpfs           5.0M  8.0K  5.0M   1% /run/lock
   tmpfs           3.8G   60K  3.8G   1% /tmp
   /dev/nvme0n1p1  300M  6.1M  294M   3% /boot/efi

There's an additional drive mounted at /media but it doesn't appear to be part of this issue.

What is your mount output showing?

You can also install the ncdu utility via sudo apt install ncdu and then run sudo ncdu / to see the disk utilization and drill down to see what files are eating up space.

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I also see that you are using this same server for media and adsb. Plex can chew though space really quickly with thumbnails and other metadata. It's possible that you are pushing to full utilization of the drive and then another process dumps that extra data to try to get back to some available space.

Throwing a watch df -h in a terminal could show you if the disk is indeed being overloaded and then purged.

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Lots of good suggestions here. I'll look at the logs and see how big they are and also look at ncdu output.

The /media drive is an external SSD with video files on it.

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Okay, and did you intend to have two IPv4 addresses on the same subnet bound to the same interface?

*** [ DIAGNOSING ]: Networking
[✓] IPv4 address(es) bound to the enp3s0 interface:
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Yes. .50 is virtual for a keep alive failover.

I have 2 separate boxes. .39 and .40. When .39 dies it fails over to .40. .39 is the real ip. .50 is the virtual one. I have my router pointing to .50 as the DNS.

I think this is the answer. Ive been adding to Plex and I have the media on this SSD. The /media drive is an external SSD that's a backup drive.

I bet Plex is dumping a ton of data at once (or when I use winscp to transfer files to .39 from the windows computer in digitizing old VHS gone videos on)

I think at some point I'll need to get a 2nd external drive and just have media on there and off then main SSD.

Ok. I had a very large log file that I deleted and I emptied the trash with a 5.gb.file in it. Since I rdp in I don't see the desktop trashcan.

Ncdu seems to be stymied because of time shift, with it saying I have some crazy high apparent TiB of files . something that isn't possible.

I think it's a transient spike from plex that's freaking out pihole and the longer term solution is getting the files off the main SSD so it has more room to do what it needs to do.

Thanks everyone.

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