Windows: UNC paths vs mapped drives

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CameronD
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Windows: UNC paths vs mapped drives

Post by CameronD » Mon Jan 27, 2014 2:41 pm

Update: the problem has to a large extent gone away, with no clear-cut reason why.

I came across this (minor) problem while looking at issues around sharing access to network drives.

Win 7 and XP PCs as domain members with a samba PDC (not sure if this is significant).

If I open a mapped drive (using a drive letter) then the response is almost immediate.
If I open the same folder, but use a UNC path reference (\\host-machine\folder\path), then there is initially a long period where XnView becomes unresponsive.
From XP client systems it is about 18 seconds, from Win 7 client systems it is 30 seconds. If the other machine is not running then it is 4 minutes.

The result is the same whether the machine sharing the folder is a Linux/samba machine, a Win 7 pc or an XP PC.

If I type the same UNC path into Windows explorer, or the "run" box, the response is immediate.

This problem does not happen on classic, or at least the problem is shifted to later, as it seems to be related to the length of time it takes the client to build up the list of remote PCs under the "network" link in the folder tree.

On an AD domain it only takes about 10 seconds to display, so I am wondering if it is something specific to Samba, or to my configuration. At least I know each of smdb, nmdb and winbindd are running.

Edit: if I reboot the client PC then the delay does not happen at all. I wonder if strange things happen when I hibernate.
Last edited by CameronD on Tue Jan 28, 2014 2:20 am, edited 1 time in total.

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m.Th.
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Re: Windows: UNC paths vs mapped drives

Post by m.Th. » Mon Jan 27, 2014 5:32 pm

Yes - hibernation definitely causes various problems with the network. Yes, I was there. :(
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CameronD
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Re: Windows: UNC paths vs mapped drives

Post by CameronD » Tue Jan 28, 2014 2:18 am

m.Th. wrote:Yes - hibernation definitely causes various problems with the network. Yes, I was there. :(
Except that there is no apparent problem with Windows explorer itself. On restarting this morning from hibernation the server connection is fast - within 1 second.
The same applies after rebooting the XP pc.
The XP machine had never been hibernated, so it could not explain those delays.

The reason I rebooted was to clear any possible caching in win explorer.

After reboot, connecting via UNC to other windows PCs was still slowish, but not consistently so. XP client to remote win-7 pc still took about 18 sec, but win7 to win-7 was only a few seconds.

I did change the winbind config a few days ago, while trying to track down this problem, but all samba services had been restarted after that. It is possible that the win-7 systems had not been rebooted since that change but the XP systems were definitely rebooted after.

Summary of current situation:
  • Win7 to server or other PC - fast
  • XP to server - 2 to 5 seconds
  • XP to other PC - 25 seconds (initial connection only)

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Re: Windows: UNC paths vs mapped drives

Post by m.Th. » Tue Jan 28, 2014 5:17 pm

I think that the problem is indeed related to your network. You must find the reason for slow discovery of the nodes of your LAN. Perhaps is better to ask on a more specialized forum for this.

Good luck!
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Re: Windows: UNC paths vs mapped drives

Post by m.Th. » Wed Jan 29, 2014 7:29 am

...and please report back your findings. :)

I'm definitely interested.
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Re: Windows: UNC paths vs mapped drives

Post by CameronD » Wed Jan 29, 2014 9:26 am

m.Th. wrote:...and please report back your findings. :)

I'm definitely interested.
At the moment the results are so scattered that I am not inclined to follow it up anywhere.
I cannot see enough consistency that I can pinpoint which group to ask - I suspect there might be multiple issues.

If win-7 starts going slow again then I will definitely follow up.

Partly it seems something to do with how the QT library handles things - At least I presume that is where the relevant code comes from. But I don't know enough to say whether it is in the library itself or how XnViewMP calls it.

I just noticed yet another peculiarity - this time on an enterprise system. If the server is not "registered" on the local section of the AD domain (what I would have previously thought of as a browse list, but don't know what it is called now) then the folder list on left remains empty. With Win explorer it gets populated in some other way. I thought this was just a Samba issue but it seems the server config problem was just revealing a problem in Qt.

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Re: Windows: UNC paths vs mapped drives

Post by m.Th. » Fri Jan 31, 2014 10:12 am

Try with another program. For example:

Free Commander (stunning orthodox file manager written in Delphi - hence no connection with Qt):

http://www.freecommander.com/fc_downl_en.htm

I'd recommend to show the Directory Tree (Alt+T) in order to see what's happening.

Also you can try Double Commander (a cross platform file manager written in Lazarus - so quite different from what we have)

http://sourceforge.net/projects/doublecmd/files/

Both file managers have a 'Thumbnail' mode - of course a very simple one which resembles Windows Explorer and not the power of XnView.

It exhibits the same problems?
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Re: Windows: UNC paths vs mapped drives

Post by CameronD » Sat Feb 01, 2014 2:35 pm

double commander was no use.
It does not even seem to have an option to directly specify a unc path - they are only accessible by following down the domain browse list. In the case of the large AD system, any attempt to browse the network resulted in "an extended error occurred".
Also I can't find a tree view so I could not investigate that problem no matter what.

Freecommander behaves like every other program - once I found the way to enter a UNC path (menu Folder -> goto Folder).
It was fast and expanded the tree list as expected - even when the server was not in the browse list. It is not the same as XnViewMP.

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Re: Windows: UNC paths vs mapped drives

Post by xnview » Tue Feb 04, 2014 3:09 pm

CameronD wrote: It was fast and expanded the tree list as expected - even when the server was not in the browse list. It is not the same as XnViewMP.
And with XnView?
Pierre.

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Re: Windows: UNC paths vs mapped drives

Post by CameronD » Wed Feb 05, 2014 12:52 am

xnview wrote:
CameronD wrote: It was fast and expanded the tree list as expected - even when the server was not in the browse list. It is not the same as XnViewMP.
And with XnView?
For the initial problems, where my samba domain was possibly misconfigured, the symptoms were exhibited by starting the program with the UNC path being the last visited folder from the previous invocation. In that case MP and classic were very different, with MP taking a long time to start up.

But on my home system, all the machines are on my browse list, so the other issue only appears with a large AD network. This network has many thousands of machines addressable by UNC path, but only 200 in the browse list for the local site.
In that case the problem is that if I refer to a server via UNC path, then the server tree does not appear in the tree list. This is the same for MP and for classic, and differs from any other software I can test that for this condition.

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