index-gw sts doc fix. closes #4583 (#4616)

* index-gw sts doc fix. closes #4583

* Update docs/sources/operations/storage/boltdb-shipper.md

Co-authored-by: Kaviraj <kavirajkanagaraj@gmail.com>

Co-authored-by: Kaviraj <kavirajkanagaraj@gmail.com>

docs/sources/operations/storage/boltdb-shipper.md

@@ -104,7 +104,7 @@ This avoids running Queriers and Rulers with a disk for persistence. Disks can b
 To run an Index Gateway, configure [StorageConfig](../../../configuration/#storage_config) and set the `-target` CLI flag to `index-gateway`.
 To connect Queriers and Rulers to the Index Gateway, set the address (with gRPC port) of the Index Gateway with the `-boltdb.shipper.index-gateway-client.server-address` CLI flag or its equivalent YAML value under [StorageConfig](../../../configuration/#storage_config).
 
-Within Kubernetes, if you are not using an Index Gateway, we recommend running an Index Gateway as a StatefulSet with persistent storage for downloading and querying index files. This will obtain better read performance, and it will avoid using node disk.
+When using the Index Gateway within Kubernetes, we recommend using a StatefulSet with persistent storage for downloading and querying index files. This can obtain better read performance, avoids [noisy neighbor problems](https://en.wikipedia.org/wiki/Cloud_computing_issues#Performance_interference_and_noisy_neighbors) by not using the node disk, and avoids the time consuming index downloading step on startup after rescheduling to a new node.
 
 ### Write Deduplication disabled