Apt speed problems after 6.17.7 on LG N1T1 NAS

Hi!

My LG N1T1 is slow, and normally apt upgrade takes a few minutes. But with 6.17.7 "Building dependency tree" took about 10 hours to 100% but then never continued. I tried:

apt autoremove
rm -f /var/cache/apt/*.bin
rm -rf /var/lib/apt/lists/*
apt clean
apt update

But it did not help.

I also have a backup script that did not work, it stopped at cat /media/data/backup/log/Backup-mail.log | ssmtp -vvv $THEEMAIL when it was supposed to email what it has done

So I tried to go back to 6.16.5 and now it is back to normal. Info about the system (from when I log in):

Model: LG N1T1
Linux version 6.16.5-kirkwood-tld-1 (root@tldDebian) (gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40) #1 PREEMPT Thu Sep  4 15:49:06 PDT 2025
Debian 13.1

What could be the issue?

raffe,

> My LG N1T1 is slow, and normally apt
> upgrade takes a few minutes. But with 6.17.7
> "Building dependency tree" took about 10 hours to
> 100% but then never continued.

It might be a coincidence, but this kernel runs differently from the 6.16.5. The 6.16.5 kernel was built with preemptive scheduler (good for response time), this 6.17.7 kernel was built with non-preemptive scheduler (good for server).

Let me try apt-get upgrade on my lowest memroy and CPU box (Pogo V4) and see if I can repeat your problem.

-bodhi
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BTW, the reason I configured this kernel to server mode was mentioned in the release notes.

Quote
https://forum.doozan.com/read.php?2,12096

- General kernel upgrade.
- This kernel is now running with the non-preempt scheduler. This is to avoid a kernel bug that was introduced recently in mainline Linux. Also, the performance should improve a little bit for Kirkwood boxes running as servers.
- Update the DTS for Promwad Thin Client
- Update the DTS for Synology DS112v10j
- See Important Note in Step 5 about uInitrd size

-bodhi
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Edited 1 time(s). Last edit at 11/11/2025 02:45PM by bodhi.

GoFlex Net

1.2GHz CPU, 128MB RAM, 1Gbs Ethernet
Linux version 6.17.7-kirkwood-tld-1 (root@tldDebian) (gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40) #1 Mon Nov  3 16:38:22 PST 2025
USB 2.0 rootfs

Took 41 minutes to upgrade from Debian 12.8 to 12.12. This is normal for a USB rootfs.

Pogo V4

800 MHz CPU, 128 MB RAM,  1Gbs Ethernet
Linux version 6.17.7-kirkwood-tld-1 (root@tldDebian) (gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40) #1 Mon Nov  3 16:38:22 PST 2025
USB 3.0 rootfs

Taking forever, but still running OK, not stuck. It seems it was spending too much time in usb_storage process. I'm not sure what's the cause.

I've aborted the upgrade and will try again with a new USB 2.0 drive.

-bodhi
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Edited 1 time(s). Last edit at 11/12/2025 03:02AM by bodhi.

raffe,

Pogo V4

800 MHz CPU, 128 MB RAM,  1Gbs Ethernet
Linux version 6.17.7-kirkwood-tld-1 (root@tldDebian) (gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40) #1 Mon Nov  3 16:38:22 PST 2025
USB 2.0 rootfs
2GB swapfile on HDD

Took 42 minutes to upgrade from Debian 12.8 to 12.12. This is normal for a USB rootfs.

It really does not matter about USB 2.0 or 3.0 rootfs. Just that the Pogo V4 draw a lot of power for USB 3.0 so I don't want that to be a factor. But swap space is important for these low power boxes.

The upgrade massively reads and writes to the rootfs, and with the 128MB RAM, the swap process is running all the time. So the swap file must be on the HDD/SSD for this to run smoothly.

Your LG N1T1 has the same specs as the Pogo V4. You need to have your swap file on the HDD. Do you?

-bodhi
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Hi, and thanks for testing!

Yes, all is on the HDD, I do not use USB.

Is there a way to during boot change from server mode?

Or maybe some other tinkering?

raffe,

> Yes, all is on the HDD, I do not use USB.

Then there is something not optimum in your rootfs. The Pogo V4 has the same specs as your LG N1T1, and I had no problem upgrading.

> Is there a way to during boot change from server
> mode?

You don't need to run the latest kernel always. If you think one does not work well for whatever reason, then don't upgrade. Wait until the next one.

> Or maybe some other tinkering?

Check the Wiki thread to see if you have done the recommended tuning.

Quote

Memory & Swap Settings

Tuning for low RAM boxes - System and HDD performance. Also read several posts after for setups for logging to RAM.
logrotate examples
How to create and use a Swap file

-bodhi
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