SharePoint 2013 Site Collection | HTTP 404 error intermittently

Problem Description

Recently I came across a weird issue, a site collection in the SharePoint farm was giving HTTP 404 intermittently. My initial thought was maybe the whole web application had the issue but didn�t see this happening with any other site collections on the same web application. And I got this error only 1 out of 10 times. But another user seemed to have got it from the first try itself. It really baffled me for couple of hours. So I did an IIS reset and even restarted the SharePoint timer service on the SharePoint web front ends. That didn�t seem to help either.

Resolution

At some point, I realized that this was a site collection specific issue. This site collection had its own dedicated database. I had to detach and attach the content database of this site collection from the web application using Powershell(read dismount and mount)to resolve this issue.

Few weeks back I had done a detach/attach of the same content database from Central Administration. I think performing dismount and mount from Central Administration console led to this behavior. I still find this weird though.

P.S.: Please make a note of the Content DB name before you start this operation

Dismount-SPContentDatabase"<ContentDBName>"

Mount-SPContentDatabase"< ContentDBName >" -DatabaseServer"<DBServerNAme>" -WebApplicationhttp://SiteName

Error while restoring a site collection in the same content database

I wanted 2 sites to be the exact same. So I was performing a backup of a site collection http://sharepoint.fahad.com/sites/siteAand was trying to restore it as http://sharepoint.fahad.com/sites/siteB.

Backup-SPSite -Identity "http://sharepoint.fahad.com/sites/siteA" -Path "C:\ Backups\siteA.bak� -force -verbose

Restore-SPSite -Identity "http://sharepoint.fahad.com/sites/siteB" �Path "C:\ Backups\siteA.bak" -force -verbose

The restore operation failed and gave me the below error:

Restore-SPSite: The operation that you are attempting to perform cannot be completed successfully.  No content databases in the web application were available to store your site collection.  The existing content databases may have reached the maximum number of site collections, or be set to read-only, or be offline, or may already contain a copy of this site collection.  Create another content database for the Web application and then try the operation again.

Reason

Both these site collections were in the same web application and it had only one content database. Microsoft uses the source site collection GUIDs during the installation. Though you delete the site collection from the web application, it leaves the GUIDs behind, and if you try to restore same site collection (same GUID) into same web application and content database, it would throw an error.

To resolve the issue, new content database needs to be created in the web application to restore the site collection.

Resolution

1.Create a new content database WSS_Content_siteB from Central Administration for your web application where your site collection is going to reside. Reference

2.Restore-SPSite -Identity "http://sharepoint.fahad.com/sites/siteB" -Path "C:\ Backups\siteA.bak" -force -verbose -ContentDatabase WSS_Content_siteB