hAP ax S freezing and rebooting during SMB upload to EXT4 drive

RouterOS General
1

I'm hitting a weird issue with my hAP ax S (ROS 7.24.4) and wanted to check if anyone else is seeing this or if there's a known workaround.

Basically, whenever I try to upload files (around 400MB) via SMB to an external drive formatted in EXT4, the router crashes or reboots after a few days of uptime.

What happens:

  • If watchdog is turned on, the router reboots by itself during the upload and the log just shows: "router was rebooted without proper shutdown by watchdog timer".

  • If I disable watchdog, the router doesn't reboot, but all active connections freeze completely during the file transfer and unblock only when the write finishes.

  • Right after a reboot, I can write files to the drive without any problem. The issue only comes back after the router has been running continuously for a few days.

  • No supout.rif is generated automatically after the reboot.

I've already tested this on two different hAP ax S units and tried several external SSDs and HDDs, all with default SMB setup and auto-mount, so it doesn't seem to be an isolated hardware defect or drive issue.

I opened a ticket about a week ago (ticket ID SUP-224396) but haven't received a reply yet, so I wanted to post here to see if this is a known bug...

Thanks for any help!

2

I had the same issue on a hap ax3 with a slow usb thumb drive.
What SSDs have you tried?

3

It gives me comfort to know I'm not the only one; I've been trying to figure out the cause for weeks...

I've tried several USB-SATA adapters, both USB 3.0 and USB 2.0, a Samsung 960 SSD, Crucial BX500, many Kingston USB flash drives, and old Toshiba HDDs.

Now I'll try to downgrade to 7.23.7... I'll let you know.
Please, if you have time, open a ticket as well.

4

Are your USB-SATA adapter bus powered or external?

Bus power might not be enough and might cause short drops on the USB

5

Externally with its own power supply.
I think it's a recent bug because in the past I used it without any issues.

6

ROS 7.23.7

After 24 hours of uptime, the router reboots on its own when I write a file to the disk via SMB.

Now I'm going to try version 7.24.1 to see if it's caused by this change:
*) disk - improve stability of the SMB server;

7

It seems resolved in version 7.24.5, I can no longer reproduce the reboot.

8

Never mind, it just rebooted...

And since support isn't responding to the ticket, I'm switching it off and using it as a doorstop

9

Ive been using btrfs on a fast SSD perfectly fine with other devices (be3 and ax3) i have an ax s i can Test with but im guessing its about device throughput dying on big transfers.

Common issue with USB flash drives when they get hot. Or HDDs with bad sectors. Or broken SSDs.
The ROS SMB Stack can't recover and seems to cause a kernel panic. You'd notice transfer speed dying even when the device is still up and then shortly after it dies

10

I checked the ext4 file system and also disabled Journaling; now CPU usage during writing has decreased a lot, but the router reboots anyway.

For now I give up, as soon as I can I will buy another HDD/SSD and try other file systems.

Thank you for your help!

11

Just tried now with a new Seagate STGX1000400 (tested with ext4 and ExFAT) and the same reboot occurs, so I rule out that the HDDs I previously tested were defective.

The same thing also happens with the hAP ac 2, except in this case there's also a Kernel Failure in the log.

I also tried limiting the write speed with queues to 5MB and it still reboots.

At this point I think it's a RouterOS bug, the only way I have left to write to the disk is WinBox or FTP.