Corruption of shared files on Citrix

#1

We have a published application (Access front end linked to Access
database) made available on a Citrix server farm. All servers are Win
2003. This application has been running for 7 years with about 50
active users, up to 8 concurrent users. Even though the front end is
shared by all users, we have never had it corrupted. However, the
database was recently corrupted and had to be compacted/repaired.

*What causes the database corruption? We are considering moving this
to SQL Server.
*How is it that we have been able to go this long without a corruption
of the front end? What factors contribute to corruption for a shared
file in a Citrix environment?

Bill Ehrreich
Hollywood, FL

#2

Bill E. wrote:

Quote:

We have a published application (Access front end linked to Access
database) made available on a Citrix server farm. All servers are Win
2003. This application has been running for 7 years with about 50
active users, up to 8 concurrent users. Even though the front end is
shared by all users, we have never had it corrupted. However, the
database was recently corrupted and had to be compacted/repaired.

*What causes the database corruption? We are considering moving this
to SQL Server.
*How is it that we have been able to go this long without a corruption
of the front end? What factors contribute to corruption for a shared
file in a Citrix environment?

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Quote:

*How is it that we have been able to go this long without a corruption
of the front end?

It was Good Luck!

Acquired knowledge is that it is ALWAYS better to have separate front
ends for each user, even in a Citrix environment.

Moving the data to SQL Server won't solve the corruption of a shared
front-end, since the users will still be using the same front-end. The
corruption is of the interface not the data.

..... unless it was the data that was corrupted. You don't say if it was
the data (the back-end) or the front-end that was corrupted. Which was
it?

Back-end corruption is just random. Easily solved by restoring a back
up and/or Compact & Repairing the back-end. Compacting & Repairing the
back-end should be a daily/weekly routine. You may not have been doing
this and it finally reached a saturation point that corrupted the back
end.

HTH,
--
MGFoster:::mgf00 <at> earthlink <decimal-point> net
Oakland, CA (USA)
** Respond only to this newsgroup. I DO NOT respond to emails **

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#3

"Bill E." <billmiami2 (AT) netscape (DOT) net> wrote:

Quote:

We have a published application (Access front end linked to Access
database) made available on a Citrix server farm. All servers are Win
2003. This application has been running for 7 years with about 50
active users, up to 8 concurrent users. Even though the front end is
shared by all users, we have never had it corrupted. However, the
database was recently corrupted and had to be compacted/repaired.

What database? FE or BE?

Quote:

*How is it that we have been able to go this long without a corruption
of the front end? What factors contribute to corruption for a shared
file in a Citrix environment?

This has nothing to do with Citrix but how Access works.

I suspect it's more a matter of programming practices that you do or don't do that
cause Access to want to save objects in the FE and thus cause corruptions.

For example if you develop against the backend then the query plans don't need
redoing on queries when they are executed.

Or sometimes Access wants to save the form in the FE when the user is using it. This
might only happen when, for example, the record source is changed or the form filter
is changed. And maybe if the form is closed specifically without saving any updates
you might not have a problem.

But these are all just guesses on my part.

It also seems that folks who mostly use macros can get away with this as well. But I
suspect it's because their systems are simpler than those who use VBA

Tony
--
Tony Toews, Microsoft Access MVP
Tony's Main MS Access pages - http://www.granite.ab.ca/accsmstr.htm
Tony's Microsoft Access Blog - http://msmvps.com/blogs/access/
Granite Fleet Manager http://www.granitefleet.com/

#4

MGFoster <me (AT) privacy (DOT) com> wrote in
news:yaGdnaFkVOmoTfXXnZ2dnUVZ_o2dnZ2d (AT) earthlink (DOT) com:

Quote:

Back-end corruption is just random.

Not really. There is usually a cause. It may not be one that is easy
to identify, and sometimes rare conditions can cause it. But if it's
happening regularly, you're doing something badly wrong.

--
David W. Fenton http://www.dfenton.com/
usenet at dfenton dot com http://www.dfenton.com/DFA/

#5

"Tony Toews [MVP]" <ttoews (AT) telusplanet (DOT) net> wrote in
news:77qh651s212goor32tb3dgrsqvhkpfmlfh (AT) 4ax (DOT) com:

Quote:

It also seems that folks who mostly use macros can get away with
this as well. But I suspect it's because their systems are
simpler than those who use VBA

It's VBA code that causes most of the problem in a shared front end,
particularly if it's not fully compiled, so that each user keeps
compiling it over and over again (and saving the compiled code).

The other area is saved filters/sorts, and that can happen in a
database without code.

--
David W. Fenton http://www.dfenton.com/
usenet at dfenton dot com http://www.dfenton.com/DFA/

#6

On Jul 24, 12:53*am, "Tony Toews [MVP]" <tto... (AT) telusplanet (DOT) net>
wrote:

Quote:

"Bill E." <billmia... (AT) netscape (DOT) net> wrote:
We have a published application (Access front end linked to Access
database) made available on a Citrix server farm. *All servers are Win
2003. *This application has been running for 7 years with about 50
active users, up to 8 concurrent users. *Even though the front end is
shared by all users, we have never had it corrupted. *However, the
database was recently corrupted and had to be compacted/repaired.

What database? *FE or BE?

*How is it that we have been able to go this long without a corruption
of the front end? *What factors contribute to corruption for a shared
file in a Citrix environment?

This has nothing to do with Citrix but how Access works.

I suspect it's more a matter of programming practices that you do or don't do that
cause Access to want to save objects in the FE and thus cause corruptions..

For example if you develop against the backend then the query plans don'tneed
redoing on queries when they are executed. *

Or sometimes Access wants to save the form in the FE when the user is using it. *This
might only happen when, for example, the record source is changed or the form filter
is changed. *And maybe if the form is closed specifically without saving any updates
you might not have a problem.

But these are all just guesses on my part.

It also seems that folks who mostly use macros can get away with this as well. *But I
suspect it's because their systems are simpler than those who use VBA

Tony
--
Tony Toews, Microsoft Access MVP
Tony's Main MS Access pages -http://www.granite.ab.ca/accsmstr.htm
Tony's Microsoft Access Blog -http://msmvps.com/blogs/access/
Granite Fleet Managerhttp://www.granitefleet.com/

My experience is that corruption goes hand in hand with bloating of
the database, that means saved changes of forms, reports, querydefs
and modules.
With proper design of forms etc. FE-users do not need to change these
objects. Flexibility can be built in through assigning new values to
all kinds of properties of an OPENED form through code. These changes
are temporarely, and are NOT saved in the form-definition.

With this way of working I have not yet experienced one time of
corruption in more than ten years.

Or am I really the lucky guy?

HBInc.

#7

hbinc <j.van.gils (AT) hccnet (DOT) nl> wrote:

Quote:

With this way of working I have not yet experienced one time of
corruption in more than ten years.

Or am I really the lucky guy?

Users only ever see MDEs so they can't changed code.

This all gets back to if you share your FE or not. If you don't then no problem. If
you do then some people get lucky and can get away with it for years.

Tony
--
Tony Toews, Microsoft Access MVP
Tony's Main MS Access pages - http://www.granite.ab.ca/accsmstr.htm
Tony's Microsoft Access Blog - http://msmvps.com/blogs/access/
Granite Fleet Manager http://www.granitefleet.com/

#8

hbinc <j.van.gils (AT) hccnet (DOT) nl> wrote in
news:9f37cf23-87b3-4767-9ace-70012382f531 (AT) r2g2000yqm (DOT) googlegroups.com
:

Quote:

With proper design of forms etc. FE-users do not need to change
these objects. Flexibility can be built in through assigning new
values to all kinds of properties of an OPENED form through code.
These changes are temporarely, and are NOT saved in the
form-definition.

With this way of working I have not yet experienced one time of
corruption in more than ten years.

There are lots of changes that get saved over which you have
absolutely no control (e.g., compiled code, filters/sorts).

Quote:

Or am I really the lucky guy?

You're very, very, very lucky.

--
David W. Fenton http://www.dfenton.com/
usenet at dfenton dot com http://www.dfenton.com/DFA/

#9

Just to clarify, we have not had a corruption of the front end, only
the back end.

Thank you for your responses.

Bill

#10

"Bill E." <billmiami2 (AT) netscape (DOT) net> wrote:

Quote:

Just to clarify, we have not had a corruption of the front end, only
the back end.

I don't think a shared FE could cause a BE to get corrupted although I suppose that's
possible.

FWIW at one client we logged all the folks as they entered the database and then
exited. We'd been doing this for years and it was quite handy. For example this
way we discovered that one printer driver in one dept was intermittently flaky and
would cause Access to crash. Once IT put on the latest drivers all was well.

The client went with a load balancing Citrix farm and it would intermittently corrupt
the back end. By the second or third time, by watching those who had logged in but
hadn't logged out, it was quite obvoius which one of the 4 Citrix servers was causing
the corruptions. Once it was removed/fixed/whatever no more problems.

For more information on corruption including possible causes, determining the
offending PC, retrieving your data, links, official MS KB articles and a list of
vendors who state they can fix corruption see the Microsoft Access Corruption FAQ at
http://www.granite.ab.ca/access/corruptmdbs.htm

Tony
--
Tony Toews, Microsoft Access MVP
Tony's Main MS Access pages - http://www.granite.ab.ca/accsmstr.htm
Tony's Microsoft Access Blog - http://msmvps.com/blogs/access/
Granite Fleet Manager http://www.granitefleet.com/