Cache utilization

View cache utilization statistics for an IBM® TS7700 Disk only or Object store cluster (TS7700 not attached to a tape library or cloud).

For each cluster, cache utilization statistics are displayed as bar graphs and tables. If a cluster is attached to a physical library or cloud, cache partitions provide statistics for each cache partition in the cache.

To view a cache utilization statistic, select it from the Select cache utilization statistics drop-down menu. Available statistics include the following.
Note: The system updates some caching statistics in the management interface, for example Physical Cache and Data in Cache, at different intervals. As a result, minor discrepancies might be observed during normal operation.
Number of virtual volumes currently in cache
The number of virtual volumes present in a cache.
Note: The number that is shown does not include flash copies of volumes.
Number of objects currently in cache
The number of objects present in a cache.
Total amount of data in cache
Total amount of data present in volumes that are assigned to a cache. If the selected cluster is a TS7720D flash copy data is not shown.
Note: Refer to the topic Data storage values in the Related Information section for additional information concerning the use of binary prefixes.
Mean duration that virtual volumes have remained in cache
The longest time a virtual volume has remained in cache preceding the end of the defined time period (last 4 hours, 48 hours, 35 days). The longest time a virtual volume has remained in cache is sampled every hour and all samples for the defined period are averaged together. Each hourly sample discards "outliers" that are greater than one and a half times the interquartile range past the third quartile. The outliers are small numbers of virtual volumes that are not representative of the cache as a whole.
Number of virtual volumes removed from cache
The number of virtual volumes that are removed from cache within the last 4 hours, according to retention group.
This statistic is only shown when the selected cluster is a non-deduplication TS7700.
Total amount of data held in cache to be copied to other clusters
Amount of data that needs to be copied to another cluster in the grid. The total amount does not include data pending replication to clusters that are unavailable or blocked. This statistic is visible only when the selected cluster is part of a grid.
Cache removal threshold setting
The removal threshold setting for the selected cluster.
This statistic is only shown when the selected cluster is a non-deduplication TS7700.

For information about the steps you can take to achieve peak network performance, refer to IBM TS7700 Series Best Practices - Understanding, Monitoring and Tuning the TS7700 Performance, WP101465, available from the TechDocs link in the Related information section.