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Storage Analytics: Transform

Storage Infrastructure into a

Business Enabler

WebTech Q&A Session September 20, 2012

1. I see on the dashboard that there are 2 ways to monitor service level objectives (SLOs) 1 for

response time and another for IOPS. Whats the difference? The average storage response time SLO monitors the weighted average of the I/O response times for all the

volumes used by the application. The response time of each volume is measured at the storage system port

and is compared to the specified SLO thresholds.The total IOPS SLO monitors an application's total I/Ooperations per second when reading from or writing to a volume.

2. What are unmonitored applications?

An unmonitored application is one not having an assigned SLO. This condition can occur when an application is

defined manually without assigning an SLO profile. Applications automatically defined by Hitachi Command

Director have a default SLO profile (monitored on response time metric) assignment and will be monitored.

Even after the SLO profile (default response time) has been assigned, the application continues to be

unmonitored until the response time data has been gathered from Hitachi Tuning Manager.

3. How can I tell if an application is frequently missing its SLO?

The SLO Investigation Unit (SIU) includes a go-back capability. In the upper left corner of the SIU, click on the

Date Time link and select a time period to display. Go to the Resources tab and click on the application of

interest. The "SLO Status (Last 24 hrs)" pane shows the applications status over the past 24 hours.

4. Is there a way Command Director can tell me which components within a storage array have reached

or are approaching their limits?

Storage Port Workload: This report shows the current workload on existing storage ports, enabling the storage

administrator to assign the best ports for new application storage or for storage offload. You can also verify hot

and cold ports by looking at fan-in/fan-out ratio as well as performance statistics. You can access this report

from the Performance category in the report gallery.

Write Pending: Average write pending percentage is the percentage of data in the cache/CLPR (cache logical

partition) that is to be written to the storage system disk. You can display the average write pending

percentage by each storage system for the past hour. Display Write Pending % By Storage System by selecting

the Avg Write Pending link in the Storage System Performance Overview report displayed on the dashboard.

Hover over the various bars to view the absolute CLPR percentage value and storage system detail.

Read Hit Ratio: This is the percentage of total read operations that are cache hits (i.e., read operations accessed

from cache) for all parity groups. You can display the total read hit ratio by each storage system for the past

hour. Display the Read Hit % By Storage System report by selecting the Avg Read Hit link in the Storage System

Performance Overview report displayed on the dashboard. Hover over the various bars to view the absolute

read hit percentage value and storage system details.

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2012, Hitachi Data Systems Corporation. All Rights Reserved.

HDP Pool Storage Performance: This report provides drill-down reports for key performance metrics that will

enable you to determine if a storage pool is overutilized from a performance perspective (IOPS, DTR, etc.). You

can access this report from the Performance category in the report gallery.

Top 20 Busiest Storage System Ports: This report provides information about the 20 busiest storage ports that

potentially impact your applications. For each port, you can drill down into the potentially impacted

applications. You can access this report from the Performance category in the report gallery.

Top 20 Busiest Parity Groups: This report provides information about the 20 busiest parity groups that could

impact back-end storage performance, applications, or the storage pools that serve your applications. You can

access this report from the Performance category in the report gallery.

Top 20 Busiest Volumes: This report provides information about the 20 busiest volumes that could impact

back-end storage performance, applications, or the storage pools that serve your applications. You can access

this report from the Performance category in the report gallery.