Capacity Planning for Windows Azure Cache Service (Preview)
The required capacity of a Cache Service (Preview) cache is determined by several factors, including the amount of data to be placed in the cache, the frequency and amount of reads and writes to the cache, and what options, such as high availability, are specified for the cache. Once the cache requirements are determined, the cache offering and size can be determined. This topic provides an overview of how to use the Capacity Planning Guide spreadsheet to determine the required capacity of the cache, and the settings to configure to provision a cache to meet the requirements.
|This topic provides guidance on how to use the Cache Service (Preview) Capacity Planning Guide spreadsheet to determine the capacity and the settings to provision a cache of the desired size. For additional guidance on determining what size may be appropriate for your application, see the Capacity Planning Methodology section of the Capacity Planning for Caching in Windows Azure whitepaper. Although the Capacity Planning for Caching in Windows Azure whitepaper contains guidance that is specific to Windows Azure Shared Caching, the guidance in the Capacity Planning Methodology section is applicable for Cache Service (Preview) and may help you determine the size of cache that meets your application's requirements. Note that this guidance is a starting point to get a sense of the capacity required based on caching requirements, and that testing is required before going into production, even for configurations recommended by this guide.|
Using the Capacity Planning Guide Spreadsheet
The Capacity Planning Guide spreadsheet is a spreadsheet that can be downloaded from the Microsoft Download Center, and can be used to assist with capacity planning.
The Windows Azure Cache – Planner worksheet is the only worksheet in the Capacity Planning Guide spreadsheet and it is used to help determine the settings for a Cache Service (Preview) cache.
The Windows Azure Cache – Planner worksheet takes several types of input. The first section, Input: Data Requirements, is used to calculate the maximum size of data for the cache. For up to ten data types, you can enter the Average Object Size (Post-Serialization), Maximum Number of Objects, and Have a backup copy of data (HA). In the previous example, there is one data type modeled. The average size is 2,048 bytes, with 250,000 as the maximum number of objects in the cache. High availability is not enabled.
The second section, Input: Throughput Requirements, is used to calculate the bandwidth requirements for the cache, and has as inputs the Number of Reads/sec and Number of Writes/sec at peak load. In this example the peak load for Data Type 1 is 1,000 reads per second and 100 writes per second.
The third section, Input: Advanced Options, provides several additional input settings. Cushion for peak load - data and Cushion for peak load - Throughput provide a buffer for surges in application load. These settings provide a convenient way to increase or decrease the desired buffer for the amount and throughput of data in the cache.
Number of named caches is used to specify how many named caches you would like for your cache. Named caches provide a way to have different caching options for different sets of data in your cache. The Basic cache offering supports a single default named cache, and the Standard and Premium cache offerings support up to ten named caches, including the default named cache.
Notifications is used to specify whether you want to use cache notifications. Cache notifications allow your applications to receive asynchronous notifications when a variety of cache operations occur on the cache. Cache notifications also provide automatic invalidation of locally cached objects. Notifications are supported in the Standard and Premium cache offerings, and are not supported in the Basic cache offering.
Once the inputs are configured, the tool provides proposals in the Output: Possible Configurations section. In this example the recommended configuration is a Basic cache with a size of 768 MB.
To use the Windows Azure Cache – Planner worksheet, enter values into the Input sections that match your caching requirements. You can use the recommended proposals as a starting point for configuring your cache. To configure your cache, see Configure the Cache.
Once your cache clients are deployed, you can monitor the health and performance of your cache by following the guidance in Monitor Windows Azure Cache Service (Preview). If you need to scale your cache up or down, follow the steps in Scale a Cache for Windows Azure Cache Service (Preview).