chore(unified-storage): add comment on new configs and some cleanup

pkg/setting/setting.go

@@ -604,7 +604,6 @@ type Cfg struct {
 	MinFileIndexBuildVersion                   string        // Minimum version of Grafana that built the file-based index. If index was built with older Grafana, it will be rebuilt asynchronously.
 	EnableSharding                             bool
 	SubIndexesPerNamespace                     int // Number of sub-indexes per (namespace, group, resource) for sharding. 0 = disabled.
-	LargeFolderThreshold                       int // Folders with more resources than this threshold get sub-sharded. 0 = disabled.
 	QOSEnabled                                 bool
 	QOSNumberWorker                            int
 	QOSMaxSizePerTenant                        int

pkg/setting/setting_unified_storage.go

@@ -102,21 +102,33 @@ func (cfg *Cfg) setUnifiedStorageConfig() {
 	}
 	cfg.EnableSearch = section.Key("enable_search").MustBool(false)
 	cfg.MaxPageSizeBytes = section.Key("max_page_size_bytes").MustInt(0)
+	// Index storage path. For Kubernetes Deployments without PVCs, use emptyDir:
+	//   index_path = /var/lib/grafana/unified-search/bleve
+	// Indexes are derived data and will be rebuilt from SQL on pod restart.
 	cfg.IndexPath = section.Key("index_path").String()
 	cfg.IndexWorkers = section.Key("index_workers").MustInt(10)
 	cfg.IndexRebuildWorkers = section.Key("index_rebuild_workers").MustInt(5)
+	// Sharding configuration for large-scale deployments (200k+ dashboards)
+	// When enable_sharding=true, indexes are distributed across pods using a ring.
+	// Each pod owns a subset of sub-indexes and rebuilds them from SQL on startup.
+	// This enables horizontal scaling without requiring PVCs (use emptyDir volumes).
 	cfg.EnableSharding = section.Key("enable_sharding").MustBool(false)
-	cfg.SubIndexesPerNamespace = section.Key("sub_indexes_per_namespace").MustInt(0) // 0 = disabled, recommended: 64 for large scale
-	cfg.LargeFolderThreshold = section.Key("large_folder_threshold").MustInt(0)      // 0 = disabled, recommended: 10000
+	cfg.SubIndexesPerNamespace = section.Key("sub_indexes_per_namespace").MustInt(0) // 0 = disabled, recommended: 64 for 1M scale
 	cfg.QOSEnabled = section.Key("qos_enabled").MustBool(false)
 	cfg.QOSNumberWorker = section.Key("qos_num_worker").MustInt(16)
 	cfg.QOSMaxSizePerTenant = section.Key("qos_max_size_per_tenant").MustInt(1000)
+	// Memberlist ring configuration for distributed search
+	// For Kubernetes Deployments, use DNS-based discovery with headless services:
+	//   memberlist_join_member = dnssrv+grafana-memberlist.namespace.svc:7946
+	// The dnssrv+ prefix triggers SRV record lookup for pod IPs.
 	cfg.MemberlistBindAddr = section.Key("memberlist_bind_addr").String()
 	cfg.MemberlistAdvertiseAddr = section.Key("memberlist_advertise_addr").String()
 	cfg.MemberlistAdvertisePort = section.Key("memberlist_advertise_port").MustInt(7946)
 	cfg.MemberlistJoinMember = section.Key("memberlist_join_member").String()
 	cfg.MemberlistClusterLabel = section.Key("memberlist_cluster_label").String()
 	cfg.MemberlistClusterLabelVerificationDisabled = section.Key("memberlist_cluster_label_verification_disabled").MustBool(false)
+	// SearchRingReplicationFactor configures replication factor of indexes across multiple instances.
+	// Recommended: 2 for production deployments using emptyDir volumes to provides availability during pod restarts/rebuilds.
 	cfg.SearchRingReplicationFactor = section.Key("search_ring_replication_factor").MustInt(1)
 	cfg.InstanceID = section.Key("instance_id").String()
 	cfg.IndexFileThreshold = section.Key("index_file_threshold").MustInt(10)

pkg/storage/unified/resource/search_server_distributor.go

@@ -44,7 +44,6 @@ func ProvideSearchDistributorServer(cfg *setting.Cfg, features featuremgmt.Featu
 		clientPool:             ringClientPool,
 		tracing:                tracer,
 		subIndexesPerNamespace: cfg.SubIndexesPerNamespace,
-		replicationFactor:      cfg.SearchRingReplicationFactor,
 	}
 
 	healthService, err := ProvideHealthService(distributorServer)
@@ -94,7 +93,6 @@ type distributorServer struct {
 	log                    log.Logger
 	tracing                trace.Tracer
 	subIndexesPerNamespace int // Number of sub-indexes per namespace (0 = disabled)
-	replicationFactor      int // Ring replication factor for replica failover
 }
 
 var (
@@ -271,7 +269,7 @@ func (ds *distributorServer) getClientToDistributeRequest(ctx context.Context, n
 		return ctx, nil, err
 	}
 
-	rs, err := ds.ring.GetWithOptions(ringHasher.Sum32(), searchRingRead, ring.WithReplicationFactor(ds.ring.ReplicationFactor()))
+	rs, err := ds.ring.GetWithOptions(ringHasher.Sum32(), searchRingRead)
 	if err != nil {
 		ds.log.Debug("error getting replication set from ring", "err", err, "namespace", namespace)
 		return ctx, nil, err
@@ -343,13 +341,7 @@ func (ds *distributorServer) getReplicasForSubIndex(subIndex SubIndexKey) ([]rin
 	if err != nil {
 		return nil, fmt.Errorf("error hashing sub-index key: %w", err)
 	}
-
-	replicationFactor := ds.replicationFactor
-	if replicationFactor <= 0 {
-		replicationFactor = ds.ring.ReplicationFactor()
-	}
-
-	rs, err := ds.ring.GetWithOptions(ringHasher.Sum32(), searchRingRead, ring.WithReplicationFactor(replicationFactor))
+	rs, err := ds.ring.GetWithOptions(ringHasher.Sum32(), searchRingRead)
 	if err != nil {
 		return nil, fmt.Errorf("error getting replication set from ring for sub-index %s: %w", subIndex.String(), err)
 	}

pkg/storage/unified/search/bleve.go

@@ -93,11 +93,6 @@ type BleveOptions struct {
 	// This enables horizontal scaling for large namespaces (1M+ documents).
 	// Recommended: 64 for large scale deployments.
 	SubIndexCount int
-
-	// LargeFolderThreshold is the resource count above which folders get sub-sharded.
-	// When a folder has more than this many resources, additional sub-sharding is applied.
-	// 0 = disabled. Recommended: 10000.
-	LargeFolderThreshold int
 }
 
 type bleveBackend struct {

pkg/storage/unified/search/options.go

@@ -55,7 +55,6 @@ func NewSearchOptions(
 			OwnsSubIndex:           ownsSubIdx,
 			IndexMinUpdateInterval: cfg.IndexMinUpdateInterval,
 			SubIndexCount:          cfg.SubIndexesPerNamespace,
-			LargeFolderThreshold:   cfg.LargeFolderThreshold,
 		}, indexMetrics)
 
 		if err != nil {

pkg/storage/unified/sql/service.go

@@ -265,7 +265,7 @@ func (s *service) OwnsSubIndex(key resource.NamespacedResource, subIndexID int)
 		}
 	}
 
-	rs, err := s.searchRing.GetWithOptions(ringHasher.Sum32(), searchOwnerRead, ring.WithReplicationFactor(s.searchRing.ReplicationFactor()))
+	rs, err := s.searchRing.GetWithOptions(ringHasher.Sum32(), searchOwnerRead)
 	if err != nil {
 		return false, fmt.Errorf("error getting replicaset from ring: %w", err)
 	}