File Sharing Limits

  • Thread starter Thread starter David Compton
  • Start date Start date
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David Compton

Hi,

We have about 40 client machines accessing (ISAM)
databases on Windows 2000 Server shared folders.
Each machine runs many programs that can access the same
databases.
Every now and then clients experience a delay in response
from the database.

I was wondering if there are any limits to the number of
simultaneous connections that can be made to a shared file
by different processes/users/machines across the network ?

I can't find any documentation on the limits of Windows
File/Print sharing.

Any ideas ?

Thanks,

Dave Compton
Systems Programmer
Autoclimate Ltd.
(e-mail address removed)
 
May depend on the database storage solution you have in place. Better to ask
the storage developer.
 
Hi Dave,

Thanks for the response.

The database files are VB/ISAM, but the problem also seems to affect our
'flat files' (binary files of UDT records accessed with PUT/GET).
We have asked the developers of the ISAM solution and there are no known
problems. They've even checked our code.

I understand that Windows 2000 Server has no limit to the number of
simultaneous connections to shares files, whereas Windows 2000 Pro had a
limit of 10 ?
I haven't seen any official word on this from Microsoft.

I would like to monitor the access to our main stock database files.
I can manually check the 'Computer Management' "System Tools\Shared
Folders\Open Files" snap-in, but I'd like to monitor, filter and log the
values every few seconds to check for patterns. Can this be done with WMI or
the Win32 API ? (I don't think there is a counter in PerfMon for individual
files is there ?).

Hope you can help - we're going to have to change our server if we don't get
this figured out soon...

Thanks again.

Dave.


Dave Patrick said:
May depend on the database storage solution you have in place. Better to ask
the storage developer.

--
Regards,

Dave Patrick ....Please no email replies - reply in newsgroup.
Microsoft MVP [Windows NT/2000 Operating Systems]

David Compton said:
Hi,

We have about 40 client machines accessing (ISAM)
databases on Windows 2000 Server shared folders.
Each machine runs many programs that can access the same
databases.
Every now and then clients experience a delay in response
from the database.

I was wondering if there are any limits to the number of
simultaneous connections that can be made to a shared file
by different processes/users/machines across the network ?

I can't find any documentation on the limits of Windows
File/Print sharing.

Any ideas ?

Thanks,

Dave Compton
Systems Programmer
Autoclimate Ltd.
(e-mail address removed)
Click to expand...
Click to expand...
 
You're correct the connection limit for any version of workstation is 10
while there is no limit for server versions. I have no experience with
VB/ISAM nor would I know what mechanism controls record/table locking, etc.
Perhaps looking at the Server object and possibly 'Files Open' and or 'Files
Opened Total' and maybe 'Server Sessions' may tell you what you want to
know.
 
Thanks again Dave. Don't mean to be rude but I'd like to offer the question out again...

Does anyone know how the 'Computer Management' "System Tools\Shared Folders\Open Files" data is gathered ?

If an MMC snap-in can read the data, then I'm sure that it can be obtained programmatically using the correct calls to the API (or whatever). If only Windows was open-source...

Firstly, the existing Performance Monitor counters are not sufficient (unless more detailed counters can be added ?).

I could enable auditing for a single database file and use DumpEL to output the data to a spreadsheet...
However calculating the concurrent connections and locks would be a nightmare and the format of the output would take a hell of a lot of work to be of use.

Where's Dan Appleman when I need him ? 8^)

I have a hunch that Windows Management Instrumentation (WMI) may be the answer - any experts on this ?

Cheers people.

Dave.

Dave Patrick said:
You're correct the connection limit for any version of workstation is 10
while there is no limit for server versions. I have no experience with
VB/ISAM nor would I know what mechanism controls record/table locking, etc.
Perhaps looking at the Server object and possibly 'Files Open' and or 'Files
Opened Total' and maybe 'Server Sessions' may tell you what you want to
know.

--
Regards,

Dave Patrick ....Please no email replies - reply in newsgroup.
Microsoft MVP [Windows NT/2000 Operating Systems]

David Compton said:
Hi Dave,

Thanks for the response.

The database files are VB/ISAM, but the problem also seems to affect our
'flat files' (binary files of UDT records accessed with PUT/GET).
We have asked the developers of the ISAM solution and there are no known
problems. They've even checked our code.

I understand that Windows 2000 Server has no limit to the number of
simultaneous connections to shares files, whereas Windows 2000 Pro had a
limit of 10 ?
I haven't seen any official word on this from Microsoft.

I would like to monitor the access to our main stock database files.
I can manually check the 'Computer Management' "System Tools\Shared
Folders\Open Files" snap-in, but I'd like to monitor, filter and log the
values every few seconds to check for patterns. Can this be done with WMI or
the Win32 API ? (I don't think there is a counter in PerfMon for individual
files is there ?).

Hope you can help - we're going to have to change our server if we don't get
this figured out soon...

Thanks again.

Dave.
Click to expand...
Click to expand...
 
You can get the same info from a command prompt;
net file

--
Regards,

Dave Patrick ....Please no email replies - reply in newsgroup.
Microsoft MVP [Windows NT/2000 Operating Systems]

:
Thanks again Dave. Don't mean to be rude but I'd like to offer the question
out again...

Does anyone know how the 'Computer Management' "System Tools\Shared
Folders\Open Files" data is gathered ?

If an MMC snap-in can read the data, then I'm sure that it can be obtained
programmatically using the correct calls to the API (or whatever). If only
Windows was open-source...

Firstly, the existing Performance Monitor counters are not sufficient
(unless more detailed counters can be added ?).

I could enable auditing for a single database file and use DumpEL to output
the data to a spreadsheet...
However calculating the concurrent connections and locks would be a
nightmare and the format of the output would take a hell of a lot of work to
be of use.

Where's Dan Appleman when I need him ? 8^)

I have a hunch that Windows Management Instrumentation (WMI) may be the
answer - any experts on this ?

Cheers people.

Dave.
 
Hmmm. I'd overlooked "NET FILE".
A Google search of "NET FILE" "API CALLS" lead me to 'NetFileEnum()'.
Thanks to some sample code from mvps.org/vbnet (Randy Birch) I can now
enumerate all files open across the network.
From there I'll be able to filter down to a specified file and use a timer
to collect data into a log.

Happy days. We've already identified several files that remain open when
they should be closed.

Mr Patrick - Your help has been very much appreciated !
 
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