HDDS-8373. Document that setquota doesn't accept decimals (#4856)

* HDDS-8373 In quota documentation setquota doesn't accepts decimals

* HDDS-8373 Addressed review comments

* HDDS-8373. Fixed checkstyle issue

---------

Co-authored-by: Arun Sarin <asarin@cloudera.com>

Author: arunsarin85

hadoop-hdds/common/src/main/java/org/apache/hadoop/hdds/client/OzoneQuota.java

@@ -191,9 +191,10 @@ public static OzoneQuota parseSpaceQuota(String quotaInBytes) {
       nSize = Long.parseLong(size);
     } catch (NumberFormatException e) {
       throw new IllegalArgumentException("Invalid values for quota, to ensure" +
-          " that the Quota format is legal(supported values are B," +
-          " KB, MB, GB and TB). And the quota value cannot be greater than " +
-          "Long.MAX_VALUE BYTES");
+              " that the Quota format is legal(supported values are B," +
+              " KB, MB, GB and TB with positive long values)." +
+              " And the quota value cannot be greater than " +
+              "Long.MAX_VALUE BYTES");
     }
 
     if (nSize <= 0) {

hadoop-hdds/docs/content/feature/Quota.md

@@ -70,6 +70,12 @@ f. If the cluster is upgraded from old version less than 1.1.0, use of quota on
 ### Storage Space level quota
 Storage space level quotas allow the use of units B, KB, MB, GB and TB. Represents how much storage Spaces will be used.
 
+#### Note:
+
+- Decimals are not supported while setting quota for volume and bucket. For example, 1.5 TB.
+
+- Ensure that the minimum storage quota is default block size * replication factor. If you set the value lesser than the default block size * replication factor, while writing the data (key put) operation, an operation error is displayed.
+
 #### Volume Storage Space level quota
 ```shell
 bin/ozone sh volume create --space-quota 5MB /volume1

hadoop-hdds/docs/content/feature/Quota.zh.md

@@ -67,6 +67,11 @@ menu:
 ## 客户端用法
 ### Storage space级别配额
 Storage space级别配额允许使用 B, KB ，MB ，GB ，TB 等单位。表示将使用多少个存储空间。
+
+#### 注意:
+- Volume 和 Bucket 不支持设置带小数点的配额值，例如 1.5 TB.
+- 最小的有效空间配额，是一个数据块需要的存储空间，即默认块大小 * 副本数. 请确保设置的空间配额不小于这个数值，不然对象/文件写入操作，会失败。
+
 #### Volume Space quota用法
 ```shell
 bin/ozone sh volume create --space-quota 5MB /volume1