The Index Protection Level for an HCI Index determines the number of identical copies of that index exist in the system. For example, for an index with an Index Protection Level of 2, two copies of that index exist in the system. If the index has multiple shards, two copies exist for each shard.
Each copy of an index is managed by one instance of the Index service. This means that in order to maintain two copies of an index, your system must have at least two instances of the Index service.
Increasing the protection level for an index has these benefits:
- An index with multiple copies remains available in the event of an outage. For example, if an index has an Index Protection Level of 2 and an instance fails, one copy of the index remains available for servicing user requests.
- Query performance is improved for an index with multiple copies because the Index service automatically directs user query requests among the index copies.
Editing Index Protection Level for an index
Your administrator can increase or decrease the Index Protection Level for all indexes.
You can increase or decrease the Index Protection Level for an index at any time. Increasing the Index Protection Level improves the availability and performance of a search index, but at the expense of requiring more disk space for storing the index.
Valid values range from 1 to a number equal to the number of instances in the system that run the Index service.
Admin App Procedure:
Click the Services window.
Click Manage Services.
Click the Index service. Then click Next.
Click the Configure window.
For each index you want, specify a value for the Index Protection Level setting.
The maximum value you can specify is equal to the number of instances that run the Index service.
Click Update Service.