Q:

Move site between site collections

I have a sharepoint 2010 environment with a site collection with many subsites. I want to re-structure the sites in the site collection into multiple site collections i.e. I want to move a site from one site collection to a different site collection. What is the best way to do this and what are the factors that I need into take into consideration (like data on the site). 
Also I want to create the new site collection on different content db.

A:

To export a site, list or document library by using Windows PowerShell
1.
Verify that you meet the following minimum requirements: See Add-SPShellAdmin.
2.
On the Start menu, click All Programs.
3.
Click Microsoft SharePoint 2010 Products.
4.
Click SharePoint 2010 Management Shell.
5.
At the Windows PowerShell command prompt (that is, PS C:>), type the following command, and then press ENTER:
Export-SPWeb -Identity  -Path  [-ItemUrl ] [-IncludeUserSecurity] [-IncludeVersions] [-NoFileCompression] [-GradualDelete] [-Verbose]
If you are exporting a large site, list, or document library, you can use the GradualDelete parameter. When this parameter is used, the site collection is marked as deleted, which immediately prevents any further access to its content. The data in the deleted site collection is then deleted gradually over time by a timer job instead of all at once, which reduces its impact on the performance of farm servers and SQL Server.
To specify which version of the site, list, or document library to include, use the IncludeVersions parameter and specify “LastMajor” (default), “CurrentVersion”, “LastMajorandMinor”, or “All”. To include the user security settings with the list or document library, use the IncludeUserSecurity parameter. If you want to overwrite the file that you specified, use the Force parameter. To view the progress of the backup operation, use the Verbose parameter.
The NoFileCompression parameter lets you specify that no file compression is performed during the export process. Using this parameter can lower resource usage up to 30% during the export process. Using this parameter will result in a backup folder being created instead of a compressed file. If you use the NoFileCompression parameter in the Export-SPWeb command, you must also use it when you import the content by using the Import-SPWeb command.
Use Central Administration to export a site, list, or document library
You can use Central Administration to export a site, list, or document library. You can only export one site, list, or document library at a time.
To export a site, list, or document library by using Central Administration
1.
Verify that the user account that is performing this procedure is a member of the Farm Administrators group.
2.
In Central Administration, on the Home page, click Backup and Restore.
3.
On the Backup and Restore page, in the Granular Backup section, click Export a site or list.
4.
On the Site or List Export page, in the Site Collection section, select the site collection from the Site Collection list, and then select the site from the Site list. 
5.
If you are exporting a site, skip this step, Select the list or document library from the List list.
6.
In the File Location section, in the Filename box, type the UNC path of the shared folder and the file to which you want to export the list or document library. The file name must use the .cmp extension.
7.
If the file already exists and you want to use this file, select the Overwrite existing files check box. Otherwise, specify a different file name.
8.
If you want to export all the security and permissions settings with the list or library, in the Export Full Security section, select the Export full security check box.
9.
If you want to specify which version of the list or library to export, select one of the following versions from the Export versions list:
 All Versions
Last Major
Current Version
Last Major and Last Minor
10.
When you have specified the settings that you want, click Start Export.
11.
You can view the status of all backup jobs at the top of the Granular Backup Job Status page. You can view the status of the current backup job in the Content Export section of the page. The status page updates every 30 seconds automatically. You can manually update the status details by clicking Refresh. Backup and recovery are Timer service jobs. Therefore, it may take several seconds for the backup to start.
If you receive any errors, you can review them in the Failure Message column of the Backup and Restore Job Status page. You can also find more details in the .export.log file at the UNC path that you specified in step 6.
http://technet.microsoft.com/en-us/library/ee428301.aspx

