Capacity Planning

The first aspect of capacity planning is separation of development, testing, quality assurance, production environments along with the separation of CMS and runtime environments.

The performance of a Sitecore runtime web server with detached database storage depends on the complexity of the site implemented and its caching configuration. Average CPU utilization per page can be used to approximate the number of pages which can be served in a given time – if each page takes 25ms to render, the machine cannot serve more than 40 pages per second, 2,400 pages per minute or 144,000 pages per hour; a rendering time of 10ms per page would result in closer to 360,000 pages per hour. Average page rendering time and peak expected user load can be used to estimate required capacity.

It is possible to host multiple websites under a single Sitecore installation by configuring the hostName for <site> entries in the <sites> section of /web.config. This may be appropriate when there is a large amount of code and/or content overlap between the sites, but when sites are independent they can also be hosted under separate document roots. Sitecore’s architecture allows multiple web and CMS servers to share the same security and extranet databases. Each website or database consumes resources.

Consider recommendations below when planning disc space for the databases:

The disc space required depends on the size of the site. 1GB would generally be a minimum disc space. A larger site may require more storage.
The databases are separated for easier administration in large-scale environments where web, extranet and/or other databases are hosted or duplicated in one or more environments. Many item properties can be inherited, which minimizes storage requirements. A Sitecore item contains all of the data for a page. An item's size can vary from 1KB to 15KB or even more, depending on the amount of content, specific layout and security settings and other values applied. This description does not account for the file system data (media and code), but the term item includes metadata about such files. This document assumes SQL Server is used.

There are seven databases behind a standard Sitecore installation, each of which varies in size and growth rate.

The size of the web and master databases depends on the number and size of items stored. The size of the master database also depends on the number of versions per item, the amount of workflow history stored and possibly other factors. An item can vary in size from 1KB. Approximate database size requirements can be calculated as follows:

50MB + (Years * Items * Versions/Year * Bytes/Version * Languages)

For instance, if four versions of 10,000 15KB items are created each year, item requirements for the master database in 5 years should be:

50 MB + (5 * 10,000 * 4 * 15,360 * 1) ~ 3 GB

Requirements for the web database would be the same if only one version of each Item is considered. So, the web database contains only the most recent version of each Item:

50MB + (Items * Bytes/Version * Languages)

The implementation of the Workflow should not make the master database more than 5% larger.

In general the remaining five databases will be more than covered by 500MB.

The archive database contains items which have been removed from the CMS and the published site but have not been permanently deleted; reserve 100MB unless archiving requirements are high, in which case, reserve enough space for the number of items which will need to be archived over the life of the database.
The core database controls the Sitecore UI and should grow minimally; reserve 100MB unless customization requirements are extreme.
The recycle bin contains items which have been removed but not purged from the CMS; reserve 100MB unless deletion will be constant or the recycle bin cannot be emptied periodically.
The sizes of the extranet and security databases depend on the number of roles and users in each domain; reserve a minimum of 10MB for each plus at least 10KB per user or simply 200MB. Multiple Sitecore instances can share individual extranet and security databases, and content can be published from a single master database to multiple web databases.

In general this analysis would indicate that one or two GB should be adequate for most Sitecore implementations.

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