> #### Sizing guidelines for the FathomTrendDatabase

> As Fathom runs, it gathers statistics on defined Fathom resources. These statistics are accumulated in several tables in the FathomTrendDatabase. Every time Fathom trends data from a resource, a sample is added to that particular table. The following example shows how the amount of data trended affects the size of the FathomTrendDatabase.

> ##### Example

> For this example, the following quantities of trends are used for one trend sample:

> - 5 alerts
> - 10 tasks (jobs and/or reports)
> - 25 database files
> - 10 areas
> - 10 checkpoints
> - 25 system disks
> - 25 file systems
> - 5 FileSize
> - 50 Database Analysis
> - 50 Index Analysis

> The following are single rows in the FathomTrendDatabase:

> - Samples
> - Activity for APW
> - Buffers
> - Index
> - I/O by type
> - Locks
> - Logging (AI and BI)
> - Records
> - Servers
> - Summary
> - Network
> - CPU
> - Memory
> - Status
> Note: If Table Statistics and Index Statistics are trended, there are 50 rows of each.

> The above resources will render approximately 12.2K worth of data stored in the FathomTrendDatabase, broken down as follows:

> - Database — 3.4K
> - System information — 4.1K
> - Configuration information (including tasks) — 3.0K
> - Index information (for all of the above samples) — 1.7K

> If Table Statistics and Index Statistics are trended, they result in 5.4K and 7.1K worth of data, respectively. Additional index information for Table and Index Statistics rows results in approximately 920 bytes.

> ##### Scenario one

> Using the quantities and values defined for the example, trending every 5 minutes for 24 hours over a 7-day period results in 2016 samples (288 5-minute periods in a day multiplied by 7 days). These 2016 samples result in a FathomTrendDatabase of approximately 28.3MB.

> ##### Scenario two

> Using the quantities and values defined for the example, trending every 15 minutes for 24 hours over a 7-day period results in 672 samples (96 15-minute periods in a day multiplied by 7 days). These 672 samples result in a FathomTrendDatabase of approximately 22.5MB.

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