[Documentation] update doc/use_multiple_volumes_how_to.md (#614)

Signed-off-by: yandongxiao <[email protected]>

doc/use_multiple_volumes_how_to.md

@@ -1,6 +1,7 @@
 # Deploy StarRocks with Multiple Volumes
 
 This document describes how to use multiple volumes to store StarRocks data.
+> Note: After installation, you are not allowed to modify the volume related fields no matter in the CRD or Helm Chart.
 
 # Deploy StarRocks with Multiple Volumes By Helm Chart
 
@@ -47,36 +48,6 @@ starrocks:
       name: be-storage
       storageCount: 2   # specify the number of volumes
       storageSize: 10Gi # the size of each volume
-  starrocksCluster:
-    enabledBe: true
-    enabledCn: true
-  starrocksCnSpec:
-    cnEnvVars:
-    # add storage_root_path in StarRocks config
-    config: |
-      sys_log_level = INFO
-      # ports for admin, web, heartbeat service
-      thrift_port = 9060
-      webserver_port = 8040
-      heartbeat_service_port = 9050
-      brpc_port = 8060
-      storage_root_path = /opt/starrocks/cn/storage0;/opt/starrocks/cn/storage1;/opt/starrocks/cn/storage2
-    image:
-      repository: starrocks/cn-ubuntu
-      tag: 3.2.2
-    replicas: 1
-    resources:
-      limits:
-        cpu: 8
-        memory: 8Gi
-      requests:
-        cpu: 1m
-        memory: 10Mi
-    storageSpec:
-      logStorageSize: 1Gi
-      name: cn
-      storageCount: 3   # specify the number of volumes
-      storageSize: 10Gi # the size of each volume
   starrocksFESpec:
     image:
       repository: starrocks/fe-ubuntu
@@ -95,7 +66,39 @@ starrocks:
 ```
 
 Note:
-
 1. add `storage_root_path` field in StarRocks config.
 2. use `storageCount` to specify the number of volumes.
-3. the `storage` directory still exists in the container, but will not be used to store data.
+3. the `storage` directory still exists in the container, but will not be used to store data.
+
+## What if I want to use different storageClass or storageSize for each volume?
+
+This feature is not supported in Helm Chart. The following is a workaround:
+
+```bash
+# starrocks-community is a helm chart repository, you can show yours by `helm repo list`
+# kube-starrocks is the name of the helm chart
+helm template starrocks starrocks-community/kube-starrocks -f ./values.yaml >./sr.yaml
+
+# From the sr.yaml, there will a Custom Resource Definition (CRD) named StarRocksCluster.
+# You can modify the CRD to use different storageClass or storageSize for each volume.
+storageVolumes:
+- name: be0-data
+storageClassName: "standard" # you can change the storageClassName
+storageSize: "10Gi"          # you can change the storageSize
+mountPath: /opt/starrocks/be/storage0
+- name: be1-data
+storageClassName: "standard"
+storageSize: "10Gi"
+mountPath: /opt/starrocks/be/storage1
+- name: be-log
+storageClassName:
+storageSize: "1Gi"
+mountPath: /opt/starrocks/be/log
+- name: be-spill
+storageClassName:
+storageSize: "0Gi"
+mountPath: /opt/starrocks/be/spill
+
+# After modifying the CRD, you can apply it to your Kubernetes cluster.
+kubectl apply -f sr.yaml
+```