Page performance is dependent on a number of variables—whether the user has caching enabled on the desktop, whether the IIS web servers are caching artifacts such as graphic and text content, how SharePoint is caching information, and how quickly SQL Server can provide content to the SharePoint farm.
SharePoint makes use of three distinct caching mechanisms by default: ASP.NET output cache, BLOB cache, and the page object cache. Each of these caching mechanisms has a representative set of counters in Performance Monitor.
ASP.Net output cache counters
Output cache setting effectiveness can be monitored by viewing the values for the following ASP.NET Applications counter group in Performance Monitor (shown in Table 5-1).
TABLE 1 Output cache counters and optimal values
| Counter name | Optimal Value | Notes |
| Cache API trim | 0 | Increases the amount of memory that is allocated to the ASP.NET output cache. |
| Cache API hit ratio | 1 for read-only sites <1 for read-write sites | Low hit ratios have mostly to do with content that has not been cached, frequently edited pages, or customized cache profiles that prevent effective caching. |
BLOB cache counters
BLOB cache setting effectiveness can be monitored by viewing the values for the following SharePoint Publishing cache counter group in Performance Monitor (shown in Table 5-2).
TABLE 2 BLOB cache counters and optimal values
| Counter name | Optimal Value | Notes |
| Total number of cache compactions | 0 | A consistently high number indicates that the cache size is too small. |
| BLOB cache % full | < 80% | Values between 80% and 100% indicate that the cache size is too small. |
| Publishing cache flushes/second | 0 | When the cache is flushed, performance is negatively affected. Site owners may be performing actions on the sites that are causing the cache to be flushed. To improve performance during peak-use hours, make sure that site owners perform these actions only during off-peak hours. |
| Publishing cache hit ratio | 1 for read-only sites <1 for read-write sites | Any time that unpublished or draft items are being interacted with, the read-write ratio is less than 1. |
Page object cache counters
Object cache setting effectiveness can be monitored by viewing the values for the following SharePoint Publishing cache counter group in Performance Monitor (shown in Table 5-3).
TABLE 3 Object cache counters and optimal values
| Counter name | Optimal Value | Notes |
| Total number of cache compactions | 0 | If this number is high, the cache size is too small for the data being requested. To improve performance, increase the size of the cache. |
| Publishing cache flushes/second | 0 | Site owners might be performing actions on the sites that are causing the cache to be flushed. To improve performance during peak-use hours, make sure that site owners perform these actions only during offpeak hours. |
| Publishing cache hit ratio | 1 for read-only sites <1 for read-write sites | If the hit ratio starts to fall, either the cache has been flushed or a significant amount of content has been added to the site. |
