Every couple of weeks, I have to power cycle the switch in order for it to work again. The SwOS is the latest 2.8.
The green lights are still on when the switch hangs but no connection is possible until power is cycled.
Is this a known bug in firmware?
I’ve had this happen too on a couple of these but it’s always been in a production/hurry situation where I haven’t been able to troubleshoot without rebooting. Super pain and sounds similar. Lights are on but no ssh, no GUI, doesn’t pass traffic.
I’m experiencing the exact same thing as well. Wanna add something though, it actually does pass/forward ICMP packets (but not other protocols) during these hangs, which I guess makes watchdog functionality entirely useless
I emailed support@mikrotik.com about this issue.
I hope they get it fixed
I have two of these in production, with one 10Gib fiber, one VLAN trunk port and about 4 VLANs each. Rock solid, with an uptime of 56 and 62 days. True, the traffic is light - but even when stress testing I didn’t get problems.
Maybe some specific configuration, triggering a bug?
Or could it be the power? Some transient, some spike? Noise on the line, maybe? They run quite cool, so I don’t think it would be temperature related.
What firmware version you using?
Are there any special configurations?
RSTP? …
I’m using firmware 2.8
RSTP, IGMP snooping, no LAG, no forwarding, VLANs and no ACLs.
Each of them has a trunk of 10Gb (module S+85DLC03D), and about 15 computers. The trunk connects them to a CRS328, where the servers are connected.
Then it’s either wrong configurations or faulty units. I thought there was something wrong with the firmware. I was on 2.8, now downgraded to 2.7 just in case. I will test it and see but probably will have to wait 6-10 days.
[edit] oops my mistake … the unit I purchased is the CRS326 and not the CCS326.
I just got one of these and under SWOS it states upgrade 2.9 available but when I upgrade and it reboots automatically the upgrade does NOT take. Tried this a few times with the exact same behavior. Not good experience.
Yes, I see this too. I don’t know where it comes from, but there is only 2.8
Don’t even try this upgrade.
It could be a defective device. I have two CSS326. Only one of them has this hangs until now. The well functioning switch has uptime ~38 days now. Could be also because it has much less traffic than the “defective” one.
We still run 2.4 on our CSS326 and it has been running fine so far. We only use it as a basic switch and don’t have any extra features or functionality turned on. I’m pretty sure we did have to reboot it once after some storms, but we are thinking it was do to one or more of our wireless backhaul radios going wacky which they occasionally do during thunderstorms. We had to reboot those as well.
We’ve been reluctant to update past 2.4 because of the reported issues.
Only time I have had one of CSS326 switches hang is when I had a problem DSL modem. The modem would crash, and after power cycling it, the switch would shortly lock up. Replaced the DSL modem after we determined that it was having a problem. Never had a problem with the switch since. Currently it is showing an uptime of 136 days. It is running version 2.8
As I understand it, 2.9 was released and immediately recalled. That left the phantom 2.9 availability.
We see te same problem.
UPDATE:
After downgrading to 2.7, the switch hanged on the fifth day.
I contacted MikroTik support and they provided me with firmware 2.9 (still beta in the testing phase I think) and now it’s been 10 days functioning well with no issues.
I am not sure whether this related or not, but I grounded the switch just before upgrading to 2.9 since I had issues with static electricity building up on the switch case. I don’t think this was the problem because as I said before, the switch keeps forwarding ICMP packets which suggests that it is not a hardware issue. I think 2.9 fixed it.
(just in case, ground your switch if it is not grounded and see if it fixes anything)
Did you receive 2.9 RC7 ?
I’m not sure of the exact version, but SwOS gui says 2.9 (built at Tue Dec 18 2018)
I have the very same problem with my CSS326 for a a very long time now and it happened with basically every firmware since v2.3, currently running v2.8: After some time - sometimes weeks, sometimes a few days, recently it was less than a day (see below) - it just locks up and would not let any traffic go through and I believe it also blocked ICMP but take this with a grain of salt. The lights on the switch’s ports keep on happily blinking, no sign of an issue from the looks of it.
Until just recently I haven’t really found a pattern, but yesterday it locked up when I did a firmware update on one of the UniFi Access Points (UAP-AC-LR) that are connected to the CSS. Power cycle of CSS fixed the issue until I did the firmware update on the other UniFi access point (UAP-AC-Lite) which again caused the CSS to hang.
The setup: UniFi Controller VM running on ESXi which is connected to CSS via 10G (direct attach cable). Each UniFi AP is connected to its respective PoE injector which in turn connects to the CSS. Management of UniFis is done via dedicated management network (which is untagged on the 1G UAP ports and tagged vlan 1 on the 10G port), the SSIDs’ traffic also runs over dedicated VLANs. I also had the UAPs connected to other physical ports until a few months ago but the issues were the same.
Do any of you who see these issues also have UniFi access points connected to your CSSes?
I will try v2.9 but I won’t let my hopes get too high since this is going on for what seems like an eternity.
Do any of you who see these issues also have UniFi access points connected to your CSSes?
Yep, I also see the same thing when I update the UniFi firmware through my CSS326-24G-2S+ but not every time. I just power-cycle the Miktrotik switch when this happens, and it’s fine until the next UniFi firmware is released…
Hi!
A also have the exact same issue, two CSS326-24G-2S+ connected with 10G (Mikrotik 3m SFP), hangs second time in a month. In a production facility.
Same storry at arrounf 6.00 in the morning… ;(
Current Installed Version 2.9 (built at Mon Jan 07 2019 12:05:03 GMT+0100 (Central European Standard Time))
I wish there was at least logging option.. or scheduled time reset.
I had to run to the factory to power cycle swithes.
Will try the lates upgrade, but have little hopes, since is the same version:
Latest Available Version 2.9 (built at Mon Jan 14 2019 07:49:36 GMT+0100 (Central European Standard Time))
Anyone found the solution?
No luck, today it happend again at arround 6 am. 
Since I don’t remember this trouble before attaching second switch on 10G link, I’ve removed it from SFPs and linked the two switches with patch cable.
I know it’s not the best solution, but just to be sure is it SFP link or something other…