Sometimes we need to install a very large Sitecore package. Depending on the size of the package and speed of your server this can be a painfully slow process. This is because Sitecore starts building indexes during the installation which can slow down everything to a crawl. To improve the speed you can simply disable Sitecore search index, install your yuuuge Sitecore package (or packages) and finally re-enable Sitecore search index again.
Below is a quick and dirty way to get this done or if you wish to implement a permanent solution you can read the article by Christian Engvall in which he walks you though steps to accomlish this.
Starting with Sitecore 7.0 rev.130810 (7.0 Update-1) you can temporarily pause indexing by executing following line of code. You can find this in the Sitecore.ContentSearch.dll
Then you install your gigantic package or packages.
And finally re-enable Sitecore search index by executing this code.
Or if you have older Sitecore version just look for the following setting in the configuration file and set the value to false to disable indexing. Then once you are done with package installation(s) set it back to true.
<setting name="Indexing.Enabled" value="false" />
TIP: If you want to monitor a Sitecore package install in real time here is a great article that shows you how to do it using PowerShell.
There you have it. If you have any questions let me know