RT-AX86U Memory Bloat

[ChrisF60526]

Hi all. I have a RT-AX86U that's been running pretty good for a few months now but over the last few days, the wireless signal has been a bit inconsistent. I took a look at the GUI and noticed that the memory seems to be pegged at around 95% for a long time. I have tried a reboot but the condition comes back.

Is this. normal or cause for concern? A factory reset is what I am thinking.

Thanks!

 

[ColinTaylor]

If you have a USB drive attached that would be normal.

 

[ChrisF60526]

If you have a USB drive attached that would be normal.

OK. Thanks. Interesting. I did add a USB drive for Time machine. So is it an issue to have the router running that full?

 

[ColinTaylor]

No it's not an issue at all. The router is using its unused memory as a disk buffer cache. This is a good thing.

 

[Tech9]

So is it an issue to have the router running that full?

In my experience testing different Asus routers - it is an issue. If you start using your router as NAS, it will run out of memory and break services. I don't know what transfers Time Machine does. I did large transfers tests on 256MB, 512MB and 1GB RAM Asus routers. They all cut Wi-Fi, WAN or other strange things happen after some time. The theory Linux manages RAM very well doesn't work when the amount of RAM is extremely limited. Your inconsistent Wi-Fi may be related issue. Better use your router as a router only.

 

[DarkKnight75]

In my experience testing different Asus routers - it is an issue. If you start using your router as NAS, it will run out of memory and break services. I don't know what transfers Time Machine does. I did large transfers tests on 256MB, 512MB and 1GB RAM Asus routers. They all cut Wi-Fi, WAN or other strange things happen after some time. The theory Linux manages RAM very well doesn't work when the amount of RAM is extremely limited. Your inconsistent Wi-Fi may be related issue. Better use your router as a router only.

Yep, exactly why i have a separate NAS box.

 

[ColinTaylor]

The theory Linux manages RAM very well doesn't work when the amount of RAM is extremely limited.

It's not a theory, Linux memory management is rock solid even on Asus routers. If there is a memory issue it's because of some other component, e.g. Samba, Broadcom kernel module, etc. But Linux can't magically correct bugs in other people's code.

 

[Tech9]

If there is a memory issue it's because of some other component, e.g. Samba, Broadcom kernel module, etc.

I don't know where the issue is. None of 512MB RAM Asus routers could complete 20GB mixed content file transfer without running out of RAM. Surprisingly, 256MB RAM model (AC68U) did it on first attempt, as well as 1GB RAM model (AX88U), but after one failed attempt. So yes, attached USB drive may break router's default functions. It depends what the drive is used for. Could be Samba, Broadcom - for the end user it doesn't matter.

 

[ChrisF60526]

We are not talking about a NAS here. We are talking about a built in feature, Time machine. No one is suggesting using your router as a NAS. My router is used as a router, a charging station (charges my phone and Apple watch), and Time machine via a USB stick.

I am still seeing 95% usage on occasion but right now, the CPU cores are barely moving and the memory is around 59%. I think we all agree that the 86U has more than enough horsepower. I was just curious as to why I was seeing 95% activity for prolonged periods.

 

[Tech9]

We are talking about a built in feature

I'm talking about advertised, but not properly working features.

a charging station (charges my phone and Apple watch)

This use may also cause router instability. Better charge your devices somewhere else.

 

[Lee MacMillan]

OK. Thanks. Interesting. I did add a USB drive for Time machine. So is it an issue to have the router running that full?

I have a USB drive on my AX86u. It was up for 120 days between reboots and RAM usage never exceeded 750MB. The drive is only used for files and is idle 99% of the time.

 

[ChrisF60526]

I continued to see more issues along with the inability to connect to wifi on the 2g band. I factory reset the router and everything cleared up. Memory usage is stable at around 42%, wifi speeds went from 300mb to 600 on my Phone 12. Not sure why but easy fix.

 

[L&LD]

The 'why' is simple to understand. With a proper/full reset to factory defaults, the router will see/use the defaults and variables in the ranges it expects (and not what may have been different in previously flashed firmware that gets carried over with 'dirty upgrades').

 

[SoCalReviews]

Sometimes new owners act like like dirty upgrades and the need to do a full factory reset is a myth. They prefer to take the easy scapegoat path by blaming their router problems on hardware failures. A few go through multiple new replacements and if they run into the same problems they get frustrated and take it even farther to say that the router design or it's components are fundamentally defective.

The key to the full factory reset is the word "proper". It needs to be performed properly to flush the memory and reset the router to the factory defaults.

 

[ChrisF60526]

What is a dirty upgrade? If you mean updating the firmware from ASUS, well, i can't see how thats an issue.

I reset the router from the app (and i have done it from the GUI in years past). That's the way it is intended to work.

 

[Tech9]

The key to the full factory reset is the word "proper".

The proper reset procedure is described clearly by Asus. If this procedure doesn't reset the router "properly", the router has an issue. Proper hardware + software product works always, not only sometimes. If you need to do some extra magic to perform a simple reset on Asus routers, there must be a wide spread flow in Asus routers. I don't think this is the case. All the routers in my collection reset properly. See how many different models here.

What is a dirty upgrade?

Forum slang - firmware update without reset to factory default afterwards. Not necessary every time, only when required in changelog or if you experience abnormal behavior. Reset just in case is only extra work for you. Some people seem to enjoy it.

 

[bbunge]

What is a dirty upgrade? If you mean updating the firmware from ASUS, well, i can't see how thats an issue.

I reset the router from the app (and i have done it from the GUI in years past). That's the way it is intended to work.

Reading over your comments, and the replies, it seems you have two unrelated issues.
First your USB drive and Time Machine. With the USB drive in the router as you are using it it does fall into the category of Network Attached Storage. So others saying NAS is not wrong. And I use my NAS as a time machine (not my router). Whenever you use the router for file storage you can expect the RAM usage to go up. Adding a swap file or partition, even on Asus firmware, can help if RAM usage gets too high. I learned a long time ago it is a good idea to have a swap on Linux just-in-case.
Second. Check the WIFI settings from a web browser. Not the app! Auto channel selection is OK but just the time you are doing something critical the router will switch channel on you. Also, check that the WIFI is using just WPA2, the 2.4 GHz is at 20 MHz and try the 5 GHz at 80 MHz. And do not use DFS channels if you are having disconnect issues! Do use Dual Band Smartconnect.
In spite of what the others have said there is nothing wrong with upgrading from a prior firmware version without a factory reset. Going from Asus to Merlin a default reset is recommended. If you do a default reset it is advisable to not restore a settings file as this could bring the prior issues back.
For a Hard Factory Reset see: https://www.asus.com/support/FAQ/1039074/
And the recent Merlin 386.4 firmware is a good deal if you need extra features!