Update readme

Author: YuryHrytsuk

charts/longhorn/README.md

@@ -2,7 +2,7 @@
 
 ### How does LH decide which node's disk to use as storage
 
-There are 3 ways https://longhorn.io/kb/tip-only-use-storage-on-a-set-of-nodes/
+There are 3 ways (could be combined together) https://longhorn.io/kb/tip-only-use-storage-on-a-set-of-nodes/
 * storag tag feature https://longhorn.io/docs/1.8.1/nodes-and-volumes/nodes/storage-tags/
 * node selectors that will restrict LH to certain nodes only (and disks on these nodes)
 * using https://longhorn.io/docs/archives/1.2.2/references/settings/#create-default-disk-on-labeled-nodes
@@ -12,3 +12,8 @@ There are 3 ways https://longhorn.io/kb/tip-only-use-storage-on-a-set-of-nodes/
 Use 2 articles below to get detailed information
 * https://longhorn.io/kb/tip-only-use-storage-on-a-set-of-nodes/
 * https://longhorn.io/docs/1.8.1/nodes-and-volumes/nodes/default-disk-and-node-config/
+
+### Running LH on subset of Nodes (via nodeSelectors) has a limitation
+
+The workloads that use PV (from LH) can only run on the nodes where LH runs. Check the Result description in the article below:
+* https://longhorn.io/kb/tip-only-use-storage-on-a-set-of-nodes/#deploy-longhorn-components-only-on-a-specific-set-of-nodes