multiple content database in SharePoint 2007 Site

Attaching Database in case there are multiple content database in SharePoint 2007 Site

If the SharePoint 2007 site contains multiple databases, then the order of attaching the content database is as follows:

1. The Content DB containing the root site collection is always applied first.
2. The other content DBs can be applied in any order.

Attach the Content DB To SharePoint 2010 Application

The process of attaching the content DBs in the SharePoint 2010 Web Application should be done through STSADM tool. For Attaching the Content DB to a SharePoint 2010 Web application, you should perform the tasks in the following order:

1. Restore the Content DBs to New SQL Server Instance
2. Delete the existing content DB of the Web application
3. Attach the Content DB of the Root Site collection

        Test-SPContentDatabase -Name -WebApplication [-AssignmentCollection ]
       [- DatabaseCredentials ] [-ServerInstance ]

      Mount-SPContentDatabase -Name <DatabaseName> -DatabaseServer <ServerName> -      WebApplication <URL> [-Updateuserexperience]

1. Attach the Content DB of other Site / Site Collections if any
2. perform an iisreset
3. Open the SharePoint 2010 Web Application
4. Perform the Visual upgrade to get the SharePoint 2010 Look and Feel

Upgrade MySite

To upgrade the MySite to SharePoint 2010, you should perform the following activities

1. Configure the My sites in SharePoint 2010
2. Perform the Content DB attachment method as discussed earlier.

SharePoint 2010 Upgrade Options

UPGRADE TYPE	PROS	CONS
In-place upgrade You have the ability to install SharePoint 2010 on the same hardware as the current version of SharePoint. You can also upgrade the content and settings in the server farm as part of a single process.	Farm-wide settings are preserved and upgraded. Customizations are available in the environment after the upgrade, although manual steps may be required to upgrade or rework them.	Servers and farms are offline while the upgrade is in progress. The upgrade proceeds continuously. Consequently, you must allocate enough time for all content to be upgraded in sequence.
Database attach upgrade You can upgrade the content for the environment on a separate farm. The result is that you do not upgrade any of the services or farm settings. You can upgrade the databases in any order and upgrade several databases at the same time.	You can upgrade multiple content databases at the same time, which results in faster upgrade times overall than an in-place upgrade. You can use a database attach upgrade to combine multiple farms into one farm.	The server and farm settings are not upgraded. You must manually transfer settings that you want to preserve from the old farm to the new farm. Any customizations must also be transferred to the new farm manually. Any missing customizations may cause unintended losses of functionality or user experience issues. Copying databases over a network takes time and bandwidth. You must plan for that. You need direct access to the database servers.
Hybrid approach 1: Read-only databases You can continue to provide read-only access to content during the upgrade process. For this approach, you set the databases to read-only while the upgrade is in progress on another farm.	The existing farm can continue to host non-upgraded sites (in read-only mode) while you upgrade the content. As a result, there is minimal downtime for users. You can upgrade multiple content databases at the same time, which results in faster upgrade times overall than an in-place upgrade. You can upgrade hardware in addition to software.	The server and farm settings are not upgraded. You must manually transfer settings that you want to preserve from the old farm to the new farm. Any customizations must also be transferred and upgraded manually. Any missing customizations may cause unintended losses of functionality or user experience issues. Copying databases over a network takes time and bandwidth. You must plan for that. You need direct access to the database servers.
Hybrid approach 2: Detach databases You can take advantage of an in-place upgrade’s ability to upgrade content and settings while adding the speed of a database attach upgrade. For this approach, you use an in-place upgrade to upgrade the farm and settings and to detach and upgrade multiple databases in parallel (on the same farm or a separate farm).	Farm-wide settings can be preserved and upgraded. Customizations are available in the environment after the upgrade, although manual steps may be required to upgrade or rework them. You can upgrade multiple content databases at the same time, which results in faster upgrade times overall than an in-place upgrade.	Copying databases over a network takes time and bandwidth. You must plan for that. You need direct access to the database servers.