About the Blockstore Metrics report

The blockstore is a feature of the Edge device installed at the branch-end of the WAN connection (typically included inside a Core at the branch site). The blockstore is an on-disk local cache that mirrors the complete persistent storage on the Core-side LUNs. The blockstore manages the block pages in the system. It reads block pages as needed, and writes block pages as they are scheduled to flush back through the Core.

The Blockstore Metrics report provides information on how well the Edge keeps up with the Core blockstore transfers, both in terms of time as well as the amount of uncommitted bytes. blockstore metrics appear only on an Edge appliance.

The Blockstore Metrics report answers these questions:

• How many read hits and misses were recorded for the blockstore for the selected LUNs for the specified period?

• How many uncommitted bytes were recorded for the blockstore for the selected LUNs for the specified period?

Mouse over a specific data point to see what the y values and exact time stamp were in relation to peaks.

The Riverbed system reports on performance for periods up to one month. Due to performance and disk space considerations, the display granularity decreases with time passed since the data was sampled.

You view the Blockstore Metrics report under Storage > Reports: Blockstore Metrics.

Use these controls to customize the report:

Specifies a report time interval of 5 minutes (5m), 1 hour (1h), 1 day (1d), 1 week (1w), All, or type a custom date. All includes statistics for the last 30 days. Time intervals that do not apply to a particular report are dimmed and unavailable.

For a custom time interval, enter the start time and end time using the format yyyy/mm/dd hh:mm:ss.

Because the system aggregates data on the hour, request hourly time intervals. For example, setting a time interval to 08:30:00 to 09:30:00 from two days ago does not create a data display, whereas setting a time interval to 08:00:00 to 09:00:00 from two days ago will display data.

When you request a custom time interval to view data beyond the aggregated granularity, the data is not visible because the system is no longer storing the data. For example, the following custom time intervals do not return data because the system automatically aggregates data older than seven days into two-hour data points:

Specifies the LUNs whose statistics you want to see from the drop-down list or select All to view all LUNs.

Specifies one of these data series from the drop-down list:

• Read Hit/Miss displays the total data read hits and average miss rate between the blockstore and the Core-side LUN(s). If no I/O occurs during a time period, the report does not include the idle time when calculating the hit rate.

• Uncommitted Data displays the amount of data committed, data written, and data uncommitted between the local Edge blockstore and the Core-side LUN(s).

Data committed is new data written to Edge and then written through Core to the back-end SAN array. The system commits all writes to Core in the order they were received.

Uncommitted data is new data written to Edge but not written through Core to the backend storage array.

Because each Edge is linked to a dedicated LUN at the data center, the blockstore is authoritative for both reads and writes, and can tolerate WAN outages without worrying about cache coherency.

• Commit Throughput displays the amount of data throughput between the blockstore and the Core-side LUN(s).

• Commit Delay displays the average time delay between a request to commit data to the blockstore and the time the data is actually committed. For example, if the Commit Delay value is 1d 3h, and the Edge at the branch office is down, any data written at the Edge in the last 1d 3h will be lost.