The Server stores all of its working data in its own central repository.  This includes all of the session data that flows through it, a full text search engine, as well as configuration data.

Enterprise Edition  vs. Standard Edition

In Standard Edition there is just one repository for the server.  In Enterprise edition you can define as many repositories as you like.  Each gets its own file storage area, storage quota, and SQL Database.

Things to Consider

When you first start the Server Administrator you must specify the directory to use for this purpose, since it has to be created to store the rest of the server configuration.  When selecting a directory, consider:

• Size:  By default, the Server can store up to 20GB of session data at any time, plus temporary working copies.  You can configure the session data pruning limits on the Loupe Server Administration - Storage Limits tab.  The total disk space used by the server is more than this space, see below.
• Accessibility:  The Server has two processes that both run with different privileges (by default).  This means the repository folder should be in a place that it can be accessible to low privilege users.  In particular, don't store the repository in a user-specific location (like My Documents or anything under the local "Users" folder) or where User Access Control restricts writing data (everywhere in the Operating System folders as well as Program Files).
• Stability:  The location takes time to change, during which the server can't receive data.  You don't want to pick a removable drive or a place you may want to relocate it from later.  It's possible to move, but involved. 

How much disk space should I have?

The server uses disk space for a few things:

• Data Retention:  This is capped once an hour to the limit you specify, but may grow by as much as an hour's worth of data between prunings.
• Transfer Cache:  When sessions are being transferred they are copied into a cache.  This cache has a limit of 2GB of size and keeps data for at least 15 minutes.  In extraordinary cases it may exceed its limit if you are transferring extremely large sessions, but will rebound into the limit within minutes of the transfers completing.
• Upload Cache:  As sessions are being uploaded they are first uploaded into a temporary area until the upload is complete.  This space isn't specifically limited but at most contains one partial session per remote client uploading data.

Taken together, we recommend having at least enough disk space to fit the repository data retention setting plus 2.5GB.  If the repository data retention setting is less than 2GB then the space reserved by cache can be similarly reduced.

What about Performance?

The server repository is not particularly disk intensive.  It is designed to work well on low performance disks as well as virtual disks.  Processor and adequate RAM are more significant concerns than disk throughput.  The SQL Server generates the most disk IO and is typically limited by disk performance.  When it is local to the server and the Server Repository then it should be located on disks with adequate performance.

Backing Up and Restoring the Server

All of the repository configuration information and data is stored underneath the folder you select.  It can be backed up as part of a routine operating system backup using Volume Shadow Copy.  The repository database file is frequently opened & closed so that it can be safely captured by a snapshot of the file and is designed to recover from any minor data issues that may result.  To restore the Server you will need to stop the web site and team service to ensure they don't interfere with the restore.  If you find yourself in this situation, please contact support so we can discussion your options to have the best result.