AC68U with Merlin 378.51 - 52_2 , losing access to USB storage drives

[Apple3141592]

I have found that the Merlin 378.5x firmware is spinning up the CPU's to peg constantly at 100% where they will not recover.
It seems that any longer duration and consistent router demands such as large file transfers will trigger this effect. Once the effect is triggered and the CPU's are pegged at 100% wireless access seems to still work on 2.5G and 5G, however access to the AC68U web server may no longer be possible, however one or more of the attached USB hard drives will most likely no longer be accessible.
I had this problem with the stock AC68U firmware from ASUS, so I changed to the Merlin firmware version RT-AC68U_3.0.0.4_376.47_0 which seemed to fix the problem. Upgrading to the newer Merlin firmware has brought the problem back. Is it possible the newer versions have incorporated some of the original ASUS code again?
It would be great to get this problem fixed as it causes a number of performance issues that seem to revolve around the CPU maxing out and not recovering.

 

[L&LD]

Did you do a reset to factory defaults after flashing the newest firmware?

 

[RussellInCincinnati]

I have found that the Merlin 378.5x firmware is spinning up the CPU's to peg constantly at 100% where they will not recover. ...

Nice to have more details. You are sharing the USB drives via SMB? Is the DLNA or other media server running, perhaps scanning huge USB drives for media files to share? How many simultaneous users?

If you just plug any old 4 gig USB device into your router with no other drives on the router, does the router still peg itself to 100% cpu usage?

How many USB drives are plugged in? Directly or through what make of hub? What are the brands and sizes of the drives? Are they NTFS/DOS/ext2/ext3 format?

What kind of clients are getting access to the files? Windows desktops, Macs, Android? OS versions of these clients?

Any other optional/installed services running? Am betting you can think of even more clues that might be relevant to someone trying to imagine what might be going on.

 

[Apple3141592]

Nice to have more details. You are sharing the USB drives via SMB? Is the DLNA or other media server running, perhaps scanning huge USB drives for media files to share? How many simultaneous users?

If you just plug any old 4 gig USB device into your router with no other drives on the router, does the router still peg itself to 100% cpu usage?

How many USB drives are plugged in? Directly or through what make of hub? What are the brands and sizes of the drives? Are they NTFS/DOS/ext2/ext3 format?

What kind of clients are getting access to the files? Windows desktops, Macs, Android? OS versions of these clients?

Any other optional/installed services running? Am betting you can think of even more clues that might be relevant to someone trying to imagine what might be going on.

I did the factory reset after the firmware upgrades.

I have no media sharing running or DLNA, it is just a simple local connection pass through to two 4TB USB drives with NTFS format that are directly plugged in to the AC68U USB ports.

There are only 2 users on the network, both are running Win 8.1. For the lock up, it only takes one robocopy script execution attempting to sync a NAS drive to one of the USB drives.
However I just found out tonight, that even playing Battlefield 4 on 2 computers will cause the CPU's to peg and lock at 100% which also results in a loss of access to the USB drives even though there was no USB drive traffic at the time. The WIFI function still seems to work fine though, the internet traffic has no issues even with the CPU's pegged, the only issue is loss of USB drive connectivity.

I am just running the factory reset configuration for this issue at this point.

Thanks for any help,

 

[Apple3141592]

Actually it isn't quite the factory reset configuration. After a few lockups I turned off QOS to attempt to reduce the load.

 

[Apple3141592]

Today I rebooted the router then just let it sit with 2 computers using WiFi for casual internet access only.
After approx. 3 hours I tried looking at the attached USB drives, I found I could no longer access them and as usual the AC68U cores were both pegged at 100%.
The only way get the cores back to normal is a reset.

 

[john9527]

Just to recap, 2 x 4GB drives, NTFS format...are they a single partition (GPT) or multiple partitions (MBR)?
Also, when the CPU goes to 100%, can you see if the drives are being accessed?

 

[bugmenotplz]

Somewhat similar issue here, the last firmware that worked without a problem was version RT-AC68U_3.0.0.4_376.49_5. All that came after exhibited the same problem, after a while, sooner or later, an hour or 2-3 days I cannot write to the disk (NTFS formatted) anymore, I can read and access it but nothing can be copied onto the disk . The drive shows in the interface like it is doing a maintenance:

ntfsck 3014.5.21
Checking NTFS Superblock ...
Device name : /dev/sda1
NTFS volume version: 3.1
Cluster size : 4096 bytes
Current volume size: 2000364237312 bytes (2000365 MB)
Current device size: 2000364240896 bytes (2000365 MB)
Checking for bad sectors ...
Scanning $MFT ...
Checking directory structure ...
Syncing device ...

And the USB icon has the red round halo. If I attempt a disk scan it stops at exactly 40% each time saying that I should remove the disk and scan it on a PC. After I do so, windows does not find any problems. I plug it back in and now I can write again for a while til the problem comes back.

 

[Minglarn]

I have similar problems with my USB flash. Once a day it says unmounted and have to remount it after removing it from the router and reinserted.

 

[Apple3141592]

Just to recap, 2 x 4GB drives, NTFS format...are they a single partition (GPT) or multiple partitions (MBR)?
Also, when the CPU goes to 100%, can you see if the drives are being accessed?

In my case, the drives are a single partition, it is possible the 100% CPU trigger is drive access, however at the time where I notice the 100% peg there is no active drive access. The CPU seems to spin in a loop with no apparent load.

 

[bugmenotplz]

Well, same in my case single partition 2 TB WD passport. In my case just one core of the cpu seem to be at 100%.

 

[Apple3141592]

Somewhat similar issue here, the last firmware that worked without a problem was version RT-AC68U_3.0.0.4_376.49_5. All that came after exhibited the same problem, after a while, sooner or later, an hour or 2-3 days I cannot write to the disk (NTFS formatted) anymore, I can read and access it but nothing can be copied onto the disk . The drive shows in the interface like it is doing a maintenance:

ntfsck 3014.5.21
Checking NTFS Superblock ...
Device name : /dev/sda1
NTFS volume version: 3.1
Cluster size : 4096 bytes
Current volume size: 2000364237312 bytes (2000365 MB)
Current device size: 2000364240896 bytes (2000365 MB)
Checking for bad sectors ...
Scanning $MFT ...
Checking directory structure ...
Syncing device ...

And the USB icon has the red round halo. If I attempt a disk scan it stops at exactly 40% each time saying that I should remove the disk and scan it on a PC. After I do so, windows does not find any problems. I plug it back in and now I can write again for a while til the problem comes back.

I have also seen the problem where a drive scan stops at 40% and reports errors. However if I remove the drive and connect it directly to one of my computers, there is absolutely nothing wrong with the drive or Windows Scans. Plugging it back in works for awhile, however I get the same results by rebooting my AC68U. It really looks like the problem is with the AC68U firmware and how it interfaces with the drives, perhaps the Linux based system is not handling the Windows based formatting properly?

 

[Denny]

I had the same problem with a very slow USB key attached.
The partition was an EXT4 partition and it was taking ages to boot the router (15 to 30 minutes). CPU was completely stuck to do the fsck (I presume).
Honestly I don't know why there was a fsck because the key doesn't have any bad clusters ... potentially because the inodes were not correctly unmounted before the reboot.
I am currently living in a country where power electricity cut is a legion (2 to 10 times a day).
The only workaround found was to boot the router without the key and then when everything was running fine to plug it in.

On this USB key, I have a chroot Debian Wheezy where I start some chrooted services.
I realized some weeks back whatever the firmware (49 to 52_2) that during the fsck, all my permissions on every folders got completely messed up.
I got 777 on every folders and files!!! I don't know what is happening here and was thinking that is was due to my slow USB key.
Then I changed this slow USB Key by a faster one (Sandisk Extreme 64 Gb).
I don't have anymore this issue of waiting ages when I reboot the rooter. At least this is "fixed" because I presume the USB Key is much more faster.
However the permissions get re-initialized at each reboot which is really annoying me. I have created a quick script (based on some FAQs) to re-initialized this but I would really want find the root cause ...
Let's see this when I will get time.

My router is a AC56U so I believe this comes from the way the fsck is implemented in the firmware

 

[Apple3141592]

I tried reverting back to 376.47 yesterday. All seemed to go well, however eventually the problem occurred again, but was a little different (most likely the same mechanism though). I noticed one of the 2 USB storage drives stopped responding, after looking at the AC68U status webpage I noticed one of the CPU cores was pegged at 100% yet the other was still acting normally and changing load as one would expect. There seems to be a problem with the AC68U firmware and how it interfaces with USB storage devices that goes back to at least 376.47. The stock ASUS code demonstrates the same problems.

 

[RussellInCincinnati]

...no media sharing running or DLNA, it is just a simple local connection pass through to two 4TB USB drives with NTFS format that are directly plugged in to the AC68U USB ports.
...even playing Battlefield 4 on 2 computers will cause the CPU's to peg and lock at 100% which also results in a loss of access to the USB drives

NTFS format is good.

What happens if you plug some USB storage device in, NTFS format, with a bunch of files on it, but capacity of less than 2 gigabytes? Without either of your current problematic 4TB devices attached.

By the way, the size of this problem is never bigger than the $100 dollars or so it would take to get a low end NAS that would handle USB storage or the drives directly, way better with far more features than a WiFi router. Or really you can for sure fix it for $40, if you consider getting a Connectland 2-drive USB 3.0 dock, can guarantee it works with an AC68u, and would also handle SATA III drives directly.
Example:
http://www.nextwarehouse.com/item/?1297595_g10e

 

[Apple3141592]

As an experiment I removed the USB storage drive that was on the USB 3.0 connection, I was able to sync files to the remaining USB 2.0 drive with no issues, the CPU load was low and very manageable for at least a day. Next I removed the drive on the USB 2.0 connection and added back the drive on the USB 3.0 connection. Syncing files to the USB 3.0 drive quickly locked up the CPU's just like before.
So... I am not sure if it is an overall load issue or something with having 2 USB drives connected, or .... whether it is a problem with a USB drive connected to the USB 3.0 connection.

 

[RussellInCincinnati]

As an experiment I removed the USB storage drive that was on the USB 3.0 connection, I was able to sync files to the remaining USB 2.0 drive with no issues, the CPU load was low and very manageable for at least a day. Next I removed the drive on the USB 2.0 connection and added back the drive on the USB 3.0 connection. Syncing files to the USB 3.0 drive quickly locked up the CPU's just like before.
So... I am not sure if it is an overall load issue or something with having 2 USB drives connected, or .... whether it is a problem with a USB drive connected to the USB 3.0 connection.

My best USB 3.0 flash drive, a quite fast one with Sandisk controller, will not work on an AC68u with _52 firmware if plugged into the USB 3 port. It works fine in the USB 2.0 port however. It also works great, alongside 3 other flash drives at the same time, when the drive are plugged into any old USB 2 hub that is in turn plugged into either USB port of an AC68u. Asus is totally handling well, multiple devices on a USB 2 hub, even printers work.

Am saying in general the AC68u 3.0 port is relatively finicky with USB 3 devices. The Connectland USB 3.0 hard disk dual bay thingy that have mentioned above does work perfectly in USB3 mode though.

 

[Apple3141592]

NTFS format is good.

What happens if you plug some USB storage device in, NTFS format, with a bunch of files on it, but capacity of less than 2 gigabytes? Without either of your current problematic 4TB devices attached.

By the way, the size of this problem is never bigger than the $100 dollars or so it would take to get a low end NAS that would handle USB storage or the drives directly, way better with far more features than a WiFi router. Or really you can for sure fix it for $40, if you consider getting a Connectland 2-drive USB 3.0 dock, can guarantee it works with an AC68u, and would also handle SATA III drives directly.
Example:
http://www.nextwarehouse.com/item/?1297595_g10e

For the USB 3.0 dock that you mentioned, how do the 2 mapped drives appear within the Router Share? As far as mapping to them do they appear as the normal drive names just as if they were individually mapped to the two USB ports?
However it would still be nice if the AC68U actually supported the features that were claimed and sold.

Thanks

 

[steven168]

i have similar problem.

cpu
Core 1 - 97 to 100%

Memory
Used 170MB
Free 64MB
Total 234MB

i using AC66U with 2 x 2TB Seagate Harddisk attach to the router.

one partition on each harddisk using NTFS.

when i copy many files and huge... sometime it hang and the copy fail and cannot access.

the router admin page also cannot load fully to show the status of the harddisk and i have to power off and on the router and everything work fine.

Asuswrt-Merlin Firmware:378.52_2

having this problem since using Asuswrt-Merlin Firmware:378.51

 

[bugmenotplz]

I've went back to Asus default
Version 3.0.0.4.378.4585
just for checking. The first improvment is that scan of the disk does not stop at 40% anymore and finishes succesfully. Till now all looks fine , will see how long it lasts.