Backing up and restoring IIS 7.0 shared configuration

I blogged a long time back about using AppCmd to back up and restore IIS 7.0 server configuration.

 

Bill also just posted about backing up and restoring configuration, where he does a great job of telling you why you need to make backups and the options you got between manual AppCmd backups and leveraging automatic Configuration History service backups.

 

This reminded me of a question I often get about backing up and restoring configuration when IIS 7.0 is being used in the Shared Configuration mode.  In this mode, the applicationHost.config file is stored on a UNC share to allow multiple IIS 7.0 servers to share a single configuration file.

 

Let me answer this question by way of illustrating what happens when you run "AppCmd Add Backup" when the IIS 7.0 server is using local configuration (default), vs shared configuration.

 

In the local configuration case, the tool will back-up the following files in the %windir%system32inetsrv directory:

  1. configapplicationHost.config
  2. configadministration.config
  3. configredirection.config
  4. configmetabase.xml
  5. configmbschema.xml
  6. All custom schema files under the configschema directory

In the shared configuration case, the tool does the same thing.

 

So, what’s my point? It’s simply that AppCmd backup commands always work with backups of the local server configuration.

 

This means that in the shared configuration case, the tool WILL NOT back up or restore the configuration located on the UNC share. However, it will back up and restore the local redirection.config file, which contains the details about where the shared configuration file is located.

 

So, if you were using local configuration at the time of backup, then moved to shared configuration, and then restored the backup, you’ll be back to your local configuration. If you were using shared configuration at the time of backup, then moved to local, then restored, you’d be back to using shared configuration (whatever it may be at this time), and your local applicationHost.config will be reset to the one saved at time of backup.

 

There is a specific reason for this design.  Imagine this scenario – you have a web farm with multiple servers using a single shared configuration file.  At some point, someone starts having trouble with one of the servers, and restores a prior configuration backup – all of a sudden, all other servers are falling over because their configuration has been reset to a configuration state that is local to the one server. Besides the fact that this could be unexpected and undesired, it could also cause all kinds of serious issues, including encryption key mismatches and configuration for features that are not installed on other web farm servers.

 

In addition to this, be aware that the Configuration History service will not back up configuration when in shared configuration mode.

 

So, moral of the story is, when using shared configuration, it is your responsibility to manage the backups of the shared configuration files.

 

With that in mind:

 

* DO perform manual backups with AppCmd (or use scheduled tasks, etc) to back up the local state even when using shared configuration. This way, you can restore the redirection.config details later if needed.

* DO perform manual backups of the shared configuration each time you make changes (or on a regular schedule), and perform manual copy of those files to the share to restore the web farm’s configuration.

* DO NOT expect to restore the web farm’s configuration by using AppCmd restore backup commands.

 

You can still depend on the local backup facilities to restore your server to its original local state, or restore the shared configuration settings as needed.

 

The only caveat to this is that if you are directly sharing configuration of one of the servers to other servers (so it’s effectively local for the “master” server), then backup/restore operations on that server will affect the entire web farm. However, I do not generally recommend doing this has its own set of limitations out of the scope of this post.

 

Hopefully this clarifies things a bit.

 

Thanks,

 

Mike

 

 

15 Comments

  1. Anonymous

    Bill’s recent post reminded me of a question I often get about backing up and restoring configuration

  2. Anonymous

    Thanks for this post. Can you say at least something about the caveat/limitations you mention in the last paragraph? Just a ballpark of what they are. Also, do you have any recommendations to handle the failure of the master server in a shared configuration setting — so that using shared configuration doesn’t result in a single point of failure?

  3. Anonymous

    Az IIS 7 egyik legfontosabb architekturális újdonsága, hogy a webkiszolgáló beállításai XML formátumú

  4. Anonymous

    In IIS6, if you didn’t backup the metabase with a password it wouldn’t let you restore it to a different server (since the encryption keys wouldnt match). Is this an issue with IIS7 or shared configuration you talk about?

  5. Anonymous

    I have a question: I ran appcmd add backup “redirect” on an IIS7.5 machine with shared config enabled, and in the backup folder there are copies of all the config files (administration.config, applicationhost.config, and redirection.config). In your post, you indicate that appcmd backups when on shared config will only backup the redirection.config file. Since my environment settings are not likely to change (with respect to configuration storage, backup, and restore), I only see reason to have one copy of this file. However, what I am concerned about is that running appcmd restore backup “redirect” will also restore the other configuration files in that folder (I am positive it will), and that copy will be much older than any backups I have made of the UNC shared config location (or the configHistory backup set).

    I suppose a better strategy would be to restore the good admin and apphost.config’s, then copy the redirect file from the backup into C:WindowsSystem32inetsrvconfig? I haven’t found a way to specify individual file restores (such as only restore apphost) using appcmd.

  6. Anonymous

    Also I noticed that the configHistory does work on shared config, you also indicate here that it won’t. Is that a change in 7.5?

  7. Anonymous

    Áttekintés Az IIS 7 egyik legfontosabb architekturális újdonsága, hogy a webkiszolgáló beállításai XML

  8. Anonymous

    Áttekintés Az IIS 7 egyik legfontosabb architekturális újdonsága, hogy a webkiszolgáló beállításai XML

  9. Anonymous

    Áttekintés Az IIS 7 egyik legfontosabb architekturális újdonsága, hogy a webkiszolgáló beállításai XML

  10. Anonymous

    IS there a way to programmatically backup IIS 7.0 and 7.5 Metabase using C#?

    The only information that I could find was using DirectoryEntry’s invoke(“Backup”, new object[0]) method, but that did not worked either

  11. Anonymous

    But how is it on IIS7 ?

    On new IIS7… this is not possible via GUI …we have to do it the old fashioned way, by typing commands on the CMD console…(running as administrator if you are on Win7 or WinServer2008)

    Gotta do as follows:
    Go CMD on windows (as adminsitrator) and go to the IIS install folder (say C:windowssystem32inetsrv) and type:

    appcmd list site

    This will list all the sites on the server…. take note of the ID for these sites, the new site you create must have a new ID.

    arcpmd list site “myOldSite” /config /xml > myXMLFile.xml
    This will create a file named “myXMLFile.xml” on the current IIS Install folder
    Edit (with notepad maybe) this file and change the ID values on the XML so it won’t conflict with any of the sites previously listed. Also change the name of the site and the binding information..

    appcmd add site “myNewSite” /in < myXMLFile.xml this will take that XML File and turn it into a new website on the server .... a perfect replica of the original ... http://churubox.blogspot.com/2010/12/iis7-how-to-backup-and-restore-one.html

    i follow the above given steps on the above link.

    but when i am restoring this single backedup website it is giving me the folowing error. would you please check and update

    Failed to process input: Invalid XML input – please make sure that your XML is
    ell-formed and follows the required format (HRESULT=8000ffff).

    pls reply on my mail id

    [email protected]io.com

  12. Akshay

    Hi,

    Is there any way to backup entire IIS along with its Website directory. that just restore it and Bingo.

    Thank you

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