SharePoint 2010 Configuration Database has a huge LOG File size problem.

You detected that SharePoint 2010 configuration database has a big LOG file size and you have  a low disk space problem.

This is happening because SharePoint Configuration Database are set to full recovery mode by default. Full recovery mode does not auto shrink / truncate the log files on a full backup. In this mode System Admins are responsible to maintaining getting Transactional Log Backups and Shrinking Log files. If Simple recovery mode is selected when you get a full backup the log files will be shrinked. But Microsoft does not recommend changing to simple recovery mode in a production environment.

You can check the Recovery mode by using SQL Server Management Studio (SSMS) by selecting “SharePoint Config” database (Right Click)-> Properties -> Options.

Full recovery mode allows the SQL admins to backup the transcation logs incrementally, simple recovery mode does not allow this and only allows full or differential backups, no transaction log backups. And Full Recorvery mode has provide you to recovery at specific time manner.

For more information about SQL Server Recovery Models
http://msdn.microsoft.com/en-us/library/ms189275.aspx

SharePoint Configuration Database is the heart of a SharePoint farm and according to size of farm lots of transactions happens.Especially every Timer Job run can cause high transactions on SharePoint Configuration Database. And There are nothing to prevent or reduce this logs rate by making any changes on SharePoint Side.

So for production enviroments SQL Admin should make a recovery and maintenance plans for preventing unnecessary growth of log files. It should be done by getting frequently Transactional Log backups and shrinking transaction log files.

The frequency has changed  system by system. It could be done 30 min to 1 day frequency, according to your transaction log growth.To prevent this kind of problem, make automize or manuelly get your Transactional backups and shrink the log files for a defined period.

For Backup Transaction Log Please check fallowing artcile:
http://msdn.microsoft.com/en-us/library/ms179478.aspx

For Shrink Transaction Log file:
http://msdn.microsoft.com/en-us/library/ms190757.aspx

Recovery Sharepoint 2010 farm when app server crushed but db is not

First do not panic . If your database is alive ,this position is not bad as seems. We have a small farm in one app server and one db. Last night app server crushed with hardware failure with unrecoverable disk error when we were getting disk image for backup purpose. If we restore last backup  so we lost last 3 days. Then we decided that setting up app server and provide to use alive db.

  1. Backup your DB for safety.
  2. Setup Sharepoint 2010 to server with “farm” and “complete” option.
  3. Do not run Sharepoint 2010 product configuration wizard if you have language packs to apply.Use your language packs first.
  4. Run Sharepoint 2010 product configuration.
  5. Do not create new farm select Connect to an existing farm option.
  6. Select your configuration DB.
  7. Click Advanced button and select  Central Administration application host for this server .
  8. After wizard finished configure your server service applications. Re-Provision if you have missing service application.
  9. You will see in IIS your  sites automatically created.
  10. Configure your web.config again and apply necessery solutions,wsp,webpart, dlls, usercontrols etc .
  11. If everything is ok. You will see your site with your content

Alternatively you can backup your site content db . Create a new farm and configure it . restore last sharepoint backup for get back in past  days and restore your site content db (Sql backup) to database for missing days.