diff --git a/cortex/config.libsonnet b/cortex/config.libsonnet
index e5622b27..d8ce8d6b 100644
--- a/cortex/config.libsonnet
+++ b/cortex/config.libsonnet
@@ -287,7 +287,8 @@
       //   max_series_per_user:   0 (disabled)
       //   max_series_per_metric: 0 (disabled)
       //
-      //   max_global_series_per_user:   100,000
+      //   // Our limit should be 100k, but we need some room of about ~50% to take rollouts into account
+      //   max_global_series_per_user:   150,000
       //   max_global_series_per_metric: 20,000
       //
       //   max_series_per_query: 10,000
diff --git a/cortex/ingester.libsonnet b/cortex/ingester.libsonnet
index d4969de1..2201351c 100644
--- a/cortex/ingester.libsonnet
+++ b/cortex/ingester.libsonnet
@@ -22,7 +22,7 @@
 
       // Limits config.
       'ingester.max-chunk-idle': $._config.max_chunk_idle,
-      'ingester.max-global-series-per-user': 100000,  // 100K
+      'ingester.max-global-series-per-user': 150000,  // 150K
       'ingester.max-global-series-per-metric': 20000,  // 20K
       'ingester.max-series-per-user': 0,  // Disabled in favour of the max global limit
       'ingester.max-series-per-metric': 0,  // Disabled in favour of the max global limit