I have been receiving complaints from my family about my home servers running Immich. They claim that it got significantly slower to load stuff especially videos but also photos. And I can vouch for them. Yes. it got slow more like sluggish…? I’m not sure. But it doesn’t feel normal because even ssh-ing into local server feels kind of sluggish now.

But the only thing that came to my mind was that I recently migrated my router facing WAN to OpenWRT router. So I suspect it has something to do with the underlying issue.

• my previous router: Tplink Archer C80
• my current (new) router: Glinet Flint 2

I flashed vanilla openwrt so the system looks like this:

System

	Hostname
		Flint2
	Model
		GL.iNet GL-MT6000
	Architecture
		ARMv8 Processor rev 4
	Target Platform
		mediatek/filogic
	Firmware Version
		OpenWrt 24.10.4 r28959-29397011cc / LuCI openwrt-24.10 branch 25.292.66247~75e41cb
	Kernel Version
		6.6.110
	Local Time
		2025-12-14 00:09:37
	Uptime
		14d 11h 56m 43s
	Load Average
		0.02, 0.01, 0.00

And CPU usage doesn’t seem to be struggling at all while I play 4k video from immich

	1 Minute Load:
		0.13
		Average:
		0.27
		Peak:
		0.57
	5 Minute Load:
		0.07
		Average:
		0.22
		Peak:
		0.50
	15 Minute Load:
		0.02
		Average:
		0.12
		Peak:
		0.30

the most suggested cause of the slowness is hardware NAT (flow offloading) being disabled by default Yes, it was for me too. But I have spent enough time (more than a week) after changing ‘flow offloading type’ to ‘Hardware flow offloading’ and don’t see any marginal improvement…

I use Tailscale for most of my homelab. I used ping function of Tailscale clients and the ping from a phone to server is 20-30ms (direct connection). I believe it was below 10 ms (direct connection) in the past setup.

It’s such a complicated issue that I need to address bit by bit. And I’ve got little to no clue/knowledge. I appreciate your help. -

I’m going to make a backup of 2TB SSD today. I will use clonezilla mainly because that’s all I know. But do you recommend any other ways for any reason?

I want to keep the process simple and easy. And I will likely take backup once a month or so repeatedly. It doesn’t have to be ready all the time. If you need more clarification, ask away.