Memory Usage at 97%

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jorgsmash

Regular Contributor
My memory usage on my AX88U is at 97%. Is there a way to see which processes are using up the most memory? I only have Diversion, Skynet, and a few other scripts installed via AMTM. I use the VPN client and the media server as well. Is there a debug I can run to post here?

upload_2020-5-17_21-38-1.png
 

ColinTaylor

Part of the Furniture
SSH into the router and run top.

The router is probably doing lots of disk accessing which will use all the memory.
 

ColinTaylor

Part of the Furniture
The CPU activity appears to have stopped now?
 

ColinTaylor

Part of the Furniture
That's fine. You've got 322MB of cache that it will free up when required.

It was almost certainly just doing some disk intensive activity.
 

jorgsmash

Regular Contributor
That's fine. You've got 322MB of cache that it will free up when required.

It was almost certainly just doing some disk intensive activity.

Ok. If I turn the media server off or unmount the disk it goes back down to about 500mb free. Is it not a concern to have the router operating at 97% memory usage for a long period of time if I always have the disk mounted or the media server on?
 

ColinTaylor

Part of the Furniture
Ok. If I turn the media server off or unmount the disk it goes back down to about 500mb free. Is it not a concern to have the router operating at 97% memory usage for a long period of time if I always have the disk mounted or the media server on?
No, that's normal. Unused memory is wasted memory. ;)
 

raven-au

Senior Member
Lol never heard that one before but it makes sense! Alrighty well thanks for helping me and thanks for the fast responses!

In that free memory can be used by the buffer cache if needed.
In that context, if free memory isn't used by the buffer cache it's wasted as it is reclaimed if needed.
 

pl4tin

Occasional Visitor
Recently I faced something similar on ac86u, I detached my external HDD and ram decrease

Enviado do meu Redmi Note 7 através do Tapatalk
 

jeden

Regular Contributor
That RAM usage widget would benefit from not including the disk buffers in the "used" count. Anybody who uses the media server feature will see their RAM is almost full which sounds like a problem, which it isn't.

https://www.linuxatemyram.com/
 

TheOtherOne

New Around Here
SSH into the router and run top.

The router is probably doing lots of disk accessing which will use all the memory.
Is there any easy fix to limit memory usage while still constantly writing to an external USB hdd plugged into the router?

I have 5 IP Cameras recording all motion events to the external hdd I plugged into the router and setup SMB shares on. Memory Usage on my RT-AX88U is always around 97%. I'm thinking this is likely the reason I'm having problems with the router locking up once or twice a week at random, requiring me to power it off and back on to get things going again.

I'm guessing the best fix would be to just not have that hdd plugged directly into the USB port on the router. I was hoping to avoid running a computer 24/7 or getting a NAS or Network drive.
 

CriticJay

Senior Member
Is there any easy fix to limit memory usage while still constantly writing to an external USB hdd plugged into the router?

I have 5 IP Cameras recording all motion events to the external hdd I plugged into the router and setup SMB shares on. Memory Usage on my RT-AX88U is always around 97%. I'm thinking this is likely the reason I'm having problems with the router locking up once or twice a week at random, requiring me to power it off and back on to get things going again.

I'm guessing the best fix would be to just not have that hdd plugged directly into the USB port on the router. I was hoping to avoid running a computer 24/7 or getting a NAS or Network drive.

I think what Colin is saying is there's no problem with an Asuswrt-Merlin router sitting at 97% memory usage, as long as you're not including "cached" in that memory total.
 

cmkelley

Very Senior Member
Is there any easy fix to limit memory usage while still constantly writing to an external USB hdd plugged into the router?

I have 5 IP Cameras recording all motion events to the external hdd I plugged into the router and setup SMB shares on. Memory Usage on my RT-AX88U is always around 97%. I'm thinking this is likely the reason I'm having problems with the router locking up once or twice a week at random, requiring me to power it off and back on to get things going again.

I'm guessing the best fix would be to just not have that hdd plugged directly into the USB port on the router. I was hoping to avoid running a computer 24/7 or getting a NAS or Network drive.
There is no "easy fix to memory usage" because there is quite literally nothing wrong.

Assuming you have a swap file on that external hdd, which I'm guessing you do since (somewhat paradoxically) "used" memory goes down when you remove it, there's no problem at all with having 97% memory "used". The term "used memory" is worse than meaningless with modern memory management. My AC86U runs continuously without reboot between Merlin updates at 94% to 97% "used".

I'd bet the reason your router is locking up is because you're using it to do something it was never intended to do, which is act as a fileserver. Somewhere in the message history here someone has done tests showing how easy it is to overload a router using it as a fileserver. Sure, for occasional use, it's fine, but if all 5 cameras decide to write at the same time, plus some other activity - say, someone streaming a video from the attached hdd, you're toying with overloading the router. The router is designed to pass packets between interfaces using inspection of the packet headers to decide if it should be passed or dropped, and if passed, where to. Sending data to/from the USB is significantly more involved, the read/write speed to a drive connected through USB is dependent on way more than raw bus speed.

TL;DR the "easy fix" is to get an ethernet-connected NAS. Your use case is likely not compatible with using the router as a fileserver.
 

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