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RT-AC86U - 384.16 - Frequent Crashes - Please Help

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salieri

Occasional Visitor
Hi,

Could really use some help/guidance here please. I recently purchased an RT-AC86U over the weekend and had frequent crashes (at least 2X a day).

Thanks, appreciate the help in advance. Let me know if there's anything else I can provide to better assist.

---

Setup:

RT-AC86U = Main Router
RT-AC68U = Wireless AiMesh Node
Drive = WD 1TB Model #WDBGPU0010BBK-NESN
Version = 384.16 (Merlin) for both routers

---

Couple of observations:

1) My AC68U was rock solid running Merlin before this upgrade. This new setup is working horribly and I'm not sure why it's so completely unstable.

2) I have a HD connected to a USB 3.0 Port on my AC86U and I'm using Samba. Whenever I seem to browse the drive, I notice my RAM usage creeps up from 75-95%. I suspect it's something with Samba.

3) Here are the items LOGGED right before the router reboots itself:

Apr 24 05:39:44 wsdd2[1688]: error: wsdd-mcast-v4: wsd_send_soap_msg: send
Apr 24 05:39:44 wsdd2[1688]: Terminated received.
Apr 24 05:39:46 kernel: *** ERROR: [udb_shell_mod_exit:661] Udb static = 0, dynamic = 48
Apr 24 05:39:49 kernel: wfd_unregisterdevice Successfully unregistered ifidx 2 wfd_idx 0
Apr 24 05:39:49 kernel: wfd_unregisterdevice Successfully unregistered ifidx 1 wfd_idx 1​

---

4) This was shown after it rebooted itself:

Apr 24 05:40:34 kernel: SHN Release Version: 2.0.1 890c91d
Apr 24 05:40:34 kernel: UDB Core Version: 0.2.18
Apr 24 05:40:34 kernel: sizeof forward pkt param = 280
Apr 24 05:40:35 avahi-daemon[982]: Alias name RT-AC86U: avahi_server_add_cname failure: The requested operation is invalid because redundant
Apr 24 05:40:35 wsdd2[1078]: Terminated received.
Apr 24 05:40:36 avahi-daemon[1663]: WARNING: No NSS support for mDNS detected, consider installing nss-mdns!
Apr 24 05:40:37 avahi-daemon[1663]: Alias name RT-AC86U: avahi_server_add_cname failure: The requested operation is invalid because redundant
---
 
Last edited:
Presume you did a full factory reset after installing Merlin and then configured all from scratch?


Sent from my iPhone using Tapatalk
 
Hmmm, maybe it’s a faulty unit. Does happen occasionally.

I’d go back to latest stock fw and bare minimum config for a day and see what happens. If it still crashes you can then get it RMA’d.


Sent from my iPhone using Tapatalk
 
Hi,

2) I have a HD connected to a USB 3.0 Port on my AC86U and I'm using Samba. Whenever I seem to browse the drive, I notice my RAM usage creeps up from 75-95%. I suspect it's something with Samba.---

I would remove the HD and see if the router is stable.
 
Hi,

Could really use some help/guidance here please. I recently purchased an RT-AC86U over the weekend and had frequent crashes (at least 2X a day).

Thanks, appreciate the help in advance. Let me know if there's anything else I can provide to better assist.

---

Setup:

RT-AC86U = Main Router
RT-AC68U = Wireless AiMesh Node
Version = 384.16 (Merlin) for both routers

---

Couple of observations:

1) My AC68U was rock solid running Merlin before this upgrade. This new setup is working horribly and I'm not sure why it's so completely unstable.

2) I have a HD connected to a USB 3.0 Port on my AC86U and I'm using Samba. Whenever I seem to browse the drive, I notice my RAM usage creeps up from 75-95%. I suspect it's something with Samba.

3) Here are the items LOGGED right before the router reboots itself:

Apr 24 05:39:44 wsdd2[1688]: error: wsdd-mcast-v4: wsd_send_soap_msg: send
Apr 24 05:39:44 wsdd2[1688]: Terminated received.
Apr 24 05:39:46 kernel: *** ERROR: [udb_shell_mod_exit:661] Udb static = 0, dynamic = 48
Apr 24 05:39:49 kernel: wfd_unregisterdevice Successfully unregistered ifidx 2 wfd_idx 0
Apr 24 05:39:49 kernel: wfd_unregisterdevice Successfully unregistered ifidx 1 wfd_idx 1​

---

4) This was shown after it rebooted itself:

Apr 24 05:40:34 kernel: SHN Release Version: 2.0.1 890c91d
Apr 24 05:40:34 kernel: UDB Core Version: 0.2.18
Apr 24 05:40:34 kernel: sizeof forward pkt param = 280
Apr 24 05:40:35 avahi-daemon[982]: Alias name RT-AC86U: avahi_server_add_cname failure: The requested operation is invalid because redundant
Apr 24 05:40:35 wsdd2[1078]: Terminated received.
Apr 24 05:40:36 avahi-daemon[1663]: WARNING: No NSS support for mDNS detected, consider installing nss-mdns!
Apr 24 05:40:37 avahi-daemon[1663]: Alias name RT-AC86U: avahi_server_add_cname failure: The requested operation is invalid because redundant
---
I have the exact setup you do, working splendidly on Merlin 384.16. I also have a samba share from my USB 3.0 SSD on my AC86U. If your drive is spinning rust, is it powered from the USB or does it have its own power supply? Some spinning rust drives can use a lot of power and if it tries to pull too much power from the USB port, it could cause a fault and cause the router to reboot.

I almost wish Merlin would remove the RAM usage meter from the GUI altogether, it doesn't tell you anything useful. Unix has varying degrees of "used" memory, so "used" memory tells a horribly incomplete story. Unix only needs a very small amount of "free" memory to work properly.

My AC86U runs ~ 95% "used" all the time. Yes, I run a lot of scripts, and I have a 2 Gb swap file on my USB drive that typically runs around 75 meg used, but I have zero problems. Perhaps use amtm to create a swap file on your usb drive ... if swap usage keeps growing, that can be a sign of a memory leak somewhere.
 
Hi,

Could really use some help/guidance here please. I recently purchased an RT-AC86U over the weekend and had frequent crashes (at least 2X a day).

Thanks, appreciate the help in advance. Let me know if there's anything else I can provide to better assist.

---

Setup:

RT-AC86U = Main Router
RT-AC68U = Wireless AiMesh Node
Version = 384.16 (Merlin) for both routers

---

Couple of observations:

1) My AC68U was rock solid running Merlin before this upgrade. This new setup is working horribly and I'm not sure why it's so completely unstable.

2) I have a HD connected to a USB 3.0 Port on my AC86U and I'm using Samba. Whenever I seem to browse the drive, I notice my RAM usage creeps up from 75-95%. I suspect it's something with Samba.

3) Here are the items LOGGED right before the router reboots itself:

Apr 24 05:39:44 wsdd2[1688]: error: wsdd-mcast-v4: wsd_send_soap_msg: send
Apr 24 05:39:44 wsdd2[1688]: Terminated received.
Apr 24 05:39:46 kernel: *** ERROR: [udb_shell_mod_exit:661] Udb static = 0, dynamic = 48
Apr 24 05:39:49 kernel: wfd_unregisterdevice Successfully unregistered ifidx 2 wfd_idx 0
Apr 24 05:39:49 kernel: wfd_unregisterdevice Successfully unregistered ifidx 1 wfd_idx 1​

---

4) This was shown after it rebooted itself:

Apr 24 05:40:34 kernel: SHN Release Version: 2.0.1 890c91d
Apr 24 05:40:34 kernel: UDB Core Version: 0.2.18
Apr 24 05:40:34 kernel: sizeof forward pkt param = 280
Apr 24 05:40:35 avahi-daemon[982]: Alias name RT-AC86U: avahi_server_add_cname failure: The requested operation is invalid because redundant
Apr 24 05:40:35 wsdd2[1078]: Terminated received.
Apr 24 05:40:36 avahi-daemon[1663]: WARNING: No NSS support for mDNS detected, consider installing nss-mdns!
Apr 24 05:40:37 avahi-daemon[1663]: Alias name RT-AC86U: avahi_server_add_cname failure: The requested operation is invalid because redundant
---

USB 3.0 mode definitely upsets 2.4 comms. With AiMesh, 2.4 is one of two wireless backhauls. I'd switch to USB 2.0 mode to see if anything improves.

OE
 
Guys, thank you so much for your responses - very much appreciated.

@cmkelley - Helpful you are running a similar config. When I read your post, I didn't really consider there being something wrong with the disk since it was working fine on my AC68U (prior router I used before purchasing this one). To answer your question, I'm running a Western Digital My Passport Ultra Drive that gets its power through the USB port (non-SSD).

On the Router, I clicked on 'USB 3.0' -> 'Health Scanner' and ran the Health Scanner.

It noted one particular thing that it ended up fixing:

Fixing $MFT bitmap
100.00 percent completed
Fixed $MFT bitmap​

I stress tested the drive for a bit (2 movies going, music) and things seem to be stable. I'll continue to monitor and see if that fixed things...
 
Guys, thank you so much for your responses - very much appreciated.

@cmkelley - Helpful you are running a similar config. When I read your post, I didn't really consider there being something wrong with the disk since it was working fine on my AC68U (prior router I used before purchasing this one). To answer your question, I'm running a Western Digital My Passport Ultra Drive that gets its power through the USB port (non-SSD).

On the Router, I clicked on 'USB 3.0' -> 'Health Scanner' and ran the Health Scanner.

It noted one particular thing that it ended up fixing:

Fixing $MFT bitmap
100.00 percent completed
Fixed $MFT bitmap​

I stress tested the drive for a bit (2 movies going, music) and things seem to be stable. I'll continue to monitor and see if that fixed things...
I hope it continues to work well for you. It would be nice if something was easy to fix for a change, eh? ;)

Unsolicited advice: I see you're also using an NTFS-formatted drive. That is perfectly fine for what you're doing, but just as an FYI, if you ever get more adventurous with your router, e.g. running some of the add-on scripts here, you will probably need to back it up, reformat it to ext4 with journaling (amtm can do the formatting for you), and restore to the newly formatted drive. NTFS works okay under linux, but some things require the drive to be in a native format. Samba can share just as well from pretty much any disk format, for instance my home file server runs FreeBSD, so the shares are all actually formatted with ZFS.
 
You need a swap file on a thumb drive.
 
-- UPDATE --- (NOT Fixed)

1) Reset Merlin Firmware 384.16 to Factory Default settings. Did 0 configuration and plugged the drive in. As soon as I started using the drive, the RAM went from ~50% back up to 95%. Letting the drive sit idle, the memory does not free up until I remove the drive from the Asus Router.

2) Flashed the router to the stock firmware 384.81369 + Factory Default Settings. Same routine as #1....0 config, RAM went from ~50% back up to 95%.

3) Prior to that I ran a diagnostic on the drive, defragged it, and it's completely healthy. Drive is a WD 1TB Model #WDBGPU0010BBK-NESN

4) I've used this drive previously on my AC68U (old) with Merlin 384.16 with 0 problems and there was no crazy spike in the RAM either.

I'm at a serious loss here. Do I just have a defective Router at this point? I would blame the drive, but like I said, it worked without a hitch on my AC68U (older) router.

Thoughts? Advice?
 
Last edited:
How are you checking RAM? The graph in the GUI lies as it doesn’t take cached memory into account so always says 95%


Sent from my iPhone using Tapatalk
 
How are you checking RAM? The graph in the GUI lies as it doesn’t take cached memory into account so always says 95%


Sent from my iPhone using Tapatalk

Yeah that's how I'm checking it and that's definitely good to know - thank you for that tip.

I just got done reflashing back the AC86U to Merlin 384.16 with Factory Defaults. I'm going to let it sit with minimal configuration and monitor for the time being.
 
@cmkelley:
I almost wish Merlin would remove the RAM usage meter from the GUI altogether, it doesn't tell you anything useful. Unix has varying degrees of "used" memory, so "used" memory tells a horribly incomplete story. Unix only needs a very small amount of "free" memory to work properly.

The ram usage is of strong value. I recently tried to uninstall "Unbound". The uninstall is broken, so when you answer "Y" it appears nothing happens, you have to watch the ram value drop to know that the action is complete. You're never prompted to reboot. It looks like it just sits there going nowhere.

This is while using "Putty" in a Windows 10 Pro environment, logged in to "AMTM" and the "GUI" at the same time.

If you could shed some light here, I'm all ears.

The reinstall to try and correct my problem was a failure (no help given), as posted here in post #1660:
https://www.snbforums.com/threads/r...or-unbound-recursive-dns-server.61669/page-83

I did find a solution that was easy (on my own) after spending an inordinate amount of time looking for a missing folder. The problem arises when updates are not synced on a more frequent schedule due to the vast frequent changes being made all the time.

Without the RAM USAGE as a visual indicator I would be stuck.
 
Do you have a swap file as @bbunge suggested? Speaking from experience, I 2nd the answer that you need a swap file on a usb key attached to the router. You can easily try this using amtm, option "sw".
 
@cmkelley:


The ram usage is of strong value. I recently tried to uninstall "Unbound". The uninstall is broken, so when you answer "Y" it appears nothing happens, you have to watch the ram value drop to know that the action is complete. You're never prompted to reboot. It looks like it just sits there going nowhere.

This is while using "Putty" in a Windows 10 Pro environment, logged in to "AMTM" and the "GUI" at the same time.

If you could shed some light here, I'm all ears.

The reinstall to try and correct my problem was a failure (no help given), as posted here in post #1660:
https://www.snbforums.com/threads/r...or-unbound-recursive-dns-server.61669/page-83

I did find a solution that was easy (on my own) after spending an inordinate amount of time looking for a missing folder. The problem arises when updates are not synced on a more frequent schedule due to the vast frequent changes being made all the time.

Without the RAM USAGE as a visual indicator I would be stuck.
Okay, so outside of your one edge case, it's doesn't tell you anything of value (the No True Scotsman defense). ;) I'm honestly surprised you could see it in ram usage, my AC86U stays at 94% all the time. It may be a function of the older kernel that the AC68U uses (2.6 vs the 4.1 in the AC86U), maybe it's more aggressive about marking memory free. I presume you've seen: https://www.linuxatemyram.com/

As to your specific problem with unbound, I couldn't tell you, I don't use it.
 
Yeah that's how I'm checking it and that's definitely good to know - thank you for that tip.

I just got done reflashing back the AC86U to Merlin 384.16 with Factory Defaults. I'm going to let it sit with minimal configuration and monitor for the time being.

Just noticed this in the 384.16 Merlin release notes [emoji23]
Code:
CHANGED: Added down/upload monitor to network status page, and removed useless RAM chart to free some space.

You can see used/free/cached on the Sys Info page btw.


Sent from my iPhone using Tapatalk
 
@cmkelley

(the No True Scotsman defense)

It may be an edge case but without the indicator I would have had to wipe and start from scratch.
I don't have experience with other models to compare the ram usage.
I do plan on a model upgrade and have been watching price points and new model releases.
Covid has disrupted so many things.

The only 2 differences between the 2 USB drives (primary and backup) were the pixelserv cert and the (Diversion blocking file size which is now on "standard" for both drives.)
These drives are not clones.
Unbound has its own cert and key and that is most likely different as well. But the uninstall reboot and reinstall did nothing for my problem.

No load ram usage is running about 120-122 but when unbound was uninstalled it dropped to 106.
The router does this:
Apr 26 09:07:53 kernel: nvram: consolidating space!

Thanks for your kind reply.
 

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