Network Share loss

[Bezwick]

Need some ideas on what to look at next.

 

We have a windows Server 2012R2 domain based network. None of the servers are reporting any problems in the logs. However we have a regular (ie more than 3 or 4 times a day) but intermittent problem where network shares randomly disconnect, printers don't deploy through group policies, and sometimes user group policies don't apply during logon but do after a reboot. Also we get random freezes when browsing through network folders for around 30 seconds.

It almost like someone is randomly pulling out a crucial network cable and then plugging it straight back in.

I have checked the switches and they are not reporting any errors, which is backed by a constant ping not being interrupted. This has been going on for a couple of weeks now and its driving me nuts. Any tips on where to look next.

 

 

Thanks

Edited June 24, 2014 by Bezwick

[Grey-gear]

You could use Wireshark to see what traffic is going on the network could give you a clue, could there be high levels of users on the network when the problems happen.

 

run a ping /t and see if any of them drop or have long ping times.

 

Has any new software been installed before this problem started to happen?

[Joanne]

A network loop can cause this issue. Do you have spanning tree enabled on all your switches?

[mikes]

We have a similar thing with Windows Server 2012 R2 and VMware (we also had it back on Server 2008 physical) - same thing - stalling when browsing shares/application hangs at the same time, unreliable print deployment etc. All pings go through OK, no errors etc. Wireshark did pick up a bunch of fragmented packets/errored packets, but it was a tiny fraction of total. We have since replaced our switches (they were Cisco ones) with Netgear stacked switches but the problem seems to remain. STP was on and portfast etc (we also had them checked out by a third party). I checked out the CPU usage/transfer rates/amounts for loops and found no indication of any. I am going to do another Wireshark in a classroom now to see what I can see

 

I am not sure if it is a network issue or a windows server issue - I have a desktop down in my Office at the very edge of the network with a local profile, local documents etc; but I do a lot of work on network shares - and I have no problems whatsoever, which I wouldn't expect if it was a core networking issue. But all of the machines on the domain / roaming profiles etc get this hanging, shares not mapping (actually reverting back to the Offline Files CSC cache despite Offline Files being disabled...)

I am not sure if it is a problem with Server 2008+'s networking stack? I was actually considering setting up a Linux fileserver to act as document/profile storage to see what would happen, but it would be a lot of work if we were barking up the wrong tree...

[pantscat]

Are you using VMware? If so - what NIC type are your VMs using?

[Bezwick]

@Grey Gear - used that a while ago and didnt notice anything out of the ordinary @Joanne - Yes we do and its not showing any issues @mikes - sounds like we are suffering the same problems @pantscat - We are using VMware on some of our servers but the Domain controllers & File server are physical Dell Machines. The servers that are vM's on VMware are either using E1000E's.

Thanks

Edited June 26, 2014 by witch

[mikes]

We had more problems with our VMware servers on E1000E - any file larger than 500mb would corrupt upon filetransfer, there is a well known bug with E1000E and data corruption (MS/VMware say it relates only to PST files, but in reality, any large files corrupt) - changing our NIC to VMXNET3 fixed that issue, but we still have the stalls etc

[pantscat]

Ok - I've seen a few recommendations to avoid using E1000E cards on VMware with iSCSI storage. The recommendation is to use VMXNET3 instead (note that this requires VMTools).

 

It's probably also worth checking out this thread: http://www.edugeek.net/forums/windows-server-2012/136984-windows-server-2012-extremely-slow-performance-executing-files.html - there's some interesting info about the SMB implementation on 2012.

[DrPerceptron]

Have you flicked through this thread? http://www.edugeek.net/forums/windows-server-2012/126721-server-2012-file-server-suddenly-stops-serving-requests-but-otherwise-looks-fine.html