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Disk Space and Memory

This appendix describes the disk space and memory requirements of the calendar server. These requirements can be broken down into the following categories:

Database Disk Space Requirements

Persistent data

Local users, resources and event calendars require disk space for calendar data. Disk space requirements for these local items can be estimated at approximately 2.5 MB per user per year, depending on usage. Note that yearly disk space requirements may be higher with heavy usage of attachments or if scheduling frequent meetings on a daily basis. The disk space requirements for remote users, resources and event calendars are therefore considerably less than those for local items, although the exact figure will depend on usage. For most deployments, where users schedule meetings with other users on the same node, this data is excluded from the preceding estimation.

Non-persistent data

Each active calendar user also has temporary data files located in the $ORACLE_HOME/ocal/db/tmp subdirectory, whose combined size should not exceed 2 MB total per configured user.

NFS Storage

UNIX installations of the Oracle Calendar server support linking the calendar database on a remote NFS file system. If you choose to do so, only the $ORACLE_HOME/ocal/db directory may be stored remotely. All other directories must remain local. This option is not recommended unless you use high-performance NFS equipment.

Large Deployment Disk Storage Recommendation

Calendar data can be broken down into two categories: persistent data and non-persistent data.

Persistent data is stored in the db/nodes directory. It is recommended to use a Redundant Array of Independent Disks (RAID) 0+1 disk storage, striped on a few disks using 8K stripe-sized blocks.

Non-persistent data is stored in the db/tmp directory. For this type of data, it is recommended to use RAID 0 disk storage, striped on a few disks. However, RAID 0+1 disk storage striped on a few disks can be used for failover. Note that a higher number of writes can be expected for non-persistent data. It is therefore recommended to optimize the db/tmp directory for write access.

Memory Requirements

The following is recommended for any large deployment with a minimum of 500 configured users on a given calendar server.

Memory requirement formula

The following general formula is used to determine the memory required on your system to offer calendar services to your user population:

Memory required = calendar sessions + calendar infrastructure + disk cache

Where a calendar session is defined as a connection to the calendar server. There is 750K of memory used per session, excluding Oracle Calendar Web client sessions.

The value calendar infrastructure is the memory used by the different calendar server processes such as CWS, DAS, etc. which adds up to 250K per user.

The disk cache is the memory required by the OS to ensure sufficient cache exists for the disk virtual memory to enhance performance. The disk cache memory needed is 250K per user.

For more information on the deployment and installation of your calendar server, see Chapter 3, "Calendar Deployment".

Table A-1 Variable definitions

Variable	Definition
`TOTAL_USERS`	Total number of configured users hosted by the server on one or many nodes.
`OCFO_USERS`	Number of configured users using Oracle Connector for Outlook.
`DESKTOP_USERS`	Number of configured users using Oracle Calendar Desktop client.
`WEB_USERS`	Number of configured users using Oracle Calendar Web client.
`FCGI_SESSIONS`	Number of fastCGI required to serve `WEB_USERS` concurrently without having a large fastCGI wait time. Varies between 2.5% to 5% of configured users.

Using the values that you determine for these variables, the following formula determines memory requirements:

(DESKTOP_USERS / 2) * 1 Meg +

(OCFO_USERS * 1 Meg) +

(FCGI_SESSIONS * 15 Meg) +

(TOTAL_USERS * 0.25 Meg)

Assumptions

`(DESKTOP_USERS / 2) * 1 Meg`

This represents the memory used by the different processes (engines, DAS, etc.) for Oracle Calendar desktop client users. The assumption is that 50% of the configured users will be logged on at the same time.

`OCFO_USERS * 1 Meg`

This represents the memory used by the different processes (engines, DAS, etc.) for Oracle Connector for Outlook configured users. The assumption is that all configured users will be remain connected throughout the day.

`FCGI_SESSIONS * 15 Meg`

For Oracle Calendar Web client sessions, the concurrency rate as well as the memory used by the different processes (engines, DAS, etc.) will be much higher than the other clients. The relationship between Web calendar users and calendar sessions is not one-to-one, one FCGI session serves many Calendar Web client users. Depending on the load and the desired peak usage, the number of FCGI sessions needed is between 2.5% and 5% of the total number of configured calendar users.

`TOTAL_USERS * 0.25 Meg`

This represents the memory required by the OS to ensure sufficient cache exists for the disk virtual memory. This is not required for disks with large cache such as EMC disks.

Note:

Additional memory will be needed if Oracle Calendar synchronization clients are used.

Example

Let us calculate the memory requirements for an organization where there will be 2500 configured calendar users. First, the number of users for each type of calendar client must be determined:

1000 Oracle Calendar Web clients

800 Outlook clients with the Oracle Connector for Outlook

700 Oracle Calendar desktop clients

Based on this distribution, compute memory requirements using the defined formula.

Memory for desktop users:

(DESKTOP_USERS / 2) * 1 Meg = (700 / 2) = 350 Meg

Memory for Outlook users:

(OCFO_USERS * 1 Meg) = 800 Meg

Memory for Web client users:

(FCGI_SESSIONS * 15 Meg) = (5% of 1000) * 15 = 50 * 15 = 750 Meg

Disk cache memory for all users:

(TOTAL_USERS * 0.25 Meg) = 2500 * 0.25 = 625 Meg

Total memory requirements for all users:

2525 Meg needed to serve this organization's 2500 calendar users.

A Disk Space and Memory