What determines the size of the .ci and .edb files in the Windows indexer?

Question

I noticed that the size of the .ci and .edb files in the Windows indexer are almost 30 GB:

What determines the size of the .ci and .edb files in the Windows indexer? I have around 4 million files, and 2 TB. I assume the more files, the larger the index files are. But is 30 GB expected for ~4 million files? I may have had more than 4 million files in the past. Does that matter?

I use Windows 7 SP1 x64 Ultimate.

Answer 1

The Windows Search Service may bloat the Windows.edb file, e.g. The Windows.edb file grows very large in Windows 8 or Windows Server 2012

How to delete and rebuild index:

1. Swipe in from the right edge of the screen, and then tap Search. Or, if you are using a mouse, point to the lower-right corner of the screen, and then click Search.
2. Tap or click Settings.
3. In the search box, type indexing options.
4. Tap or click Indexing Options.
5. Tap or click Advanced.
6. Tap or click Rebuild on the Indexing Settings tab.
7. Tap or click OK to confirm.

Answer 2

The Windows Search Service may bloat the Windows.edb file, and Exchange Search Service can influence .ci file.

From my search:

it is safe to delete the catalog files. (stop the service first) However, it is part of the Search index and some things will not be available for searching. If search isn’t that necessary, stopping the service altogether and just deleting the files. Then, he can have people use Cached Exchange mode and search the local machine (.ost file) for the messages. Having that search index is for server side searching only; such as when you search while NOT using cached exchange mode, or Outlook Web Access (OWA).

By design, you can either index or not. MS does not allow moving the content index to another drive.