Performance SLA
NetApp Keystone offers latency-based SLA per service level, as described in the Keystone order for consumed capacity up to the burst limit, according to the following listed terms and conditions.
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SLAs and guarantees are available on a nomination basis. |
Metrics
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Degraded performance: The amount of time, in minutes, per incident, during which the 90th percentile latency target is not met.
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The 90th percentile latency is measured per volume, per performance level, for all volumes within a Keystone Order. Latency is sampled every five minutes, and the 90th percentile value calculated over a 24-hour period is used as the daily measure, considering the following points:
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The volumes that record at least five IOPS at the time of metrics collection are considered for a sample.
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Volumes with greater than 30% write operations at the time of metrics collection are excluded from the sample.
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Latency added by AQoS for requested IOPS/TiB that is greater than target IOPS/TiB are excluded from the sample.
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Latency added by AQoS to maintain minimum IOPS per volume are excluded from the sample.
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For volumes that have FabricPool enabled, the latency incurred due to the transfer of data to and from the target (cold) storage is not counted.
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Latency caused by the application, host, or customer network outside of the ONTAP cluster is not counted.
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When using the advanced data protection add-on service, the target latency includes only IO operations to and from the local storage array.
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During a 24-hour period, at least ten valid metrics should be available. If not, the metrics will be discarded.
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If one or more volumes on a storage array do not have a valid AQoS policy applied, then number of IOPS available to other volumes may be affected, and NetApp will not be responsible for targeting or meeting performance levels on that storage array.
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In FabricPool configurations, performance levels are applicable when all requested data blocks are on FabricPool source (hot) storage and the source storage is not in a SnapMirror Synchronous relationship.
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Service levels
All service levels that ONTAP flash storage arrays support are eligible for Performance SLA and guarantee meeting the following target latency:
Service level |
Extreme |
Premium |
Performance |
Standard |
Target 90th percentile latency |
<1ms |
<2ms |
<4ms |
<4ms |
To learn more about the latency requirements of the service levels, refer to Service Levels in Keystone.
Service credits
NetApp issues service credits for the degraded performance:
Performance threshold |
Service credit |
90th percentile latency > target latency |
3% for each calendar day of occurrence |
Service credit calculation
Service credits are determined using the following formula:
Service credits = (impacted capacity / total committed capacity) X capacity fees X affected days X credit percentage
Where:
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impacted capacity: The amount of stored capacity affected.
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total committed capacity: The committed capacity for the service level for the Keystone order.
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capacity fees: The fees for the affected performance level as per the Keystone order.
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affected days: The number of calendar days impacted.
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credit percentage: The predetermined percentage for service credit.
Example
The following example shows the method of calculation for service credits:
Service level |
Impacted capacity |
Total committed capacity |
Capacity fees |
Affected calender days |
Credit percentage |
Extreme |
10 Tib |
50 Tib |
$1000 |
2 |
3% |
Using the formula:
Service credits = ( 10 / 50 ) X 1000 x 2 x 0.03
Based on calculation, the service credits will be $12.
Service credit request
If a breach of the SLA is detected, open a priority 3 (P3) support ticket with Keystone Global Services and Support Center (GSSC).
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The following details are required:
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Keystone subscription number
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Volumes and storage controller details
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Site, time, date, and description of the issue
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Calculated time duration of latency detection
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Measurement tools and methods
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Any other applicable document
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Provide the details in the excel sheet as shown below for a P3 ticket opened with Keystone GSSC.
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