Table 8-4 shows the possible alert severities. Table 8-4 Alert severities Option Description Critical Alert is critical and needs to be resolved. For example, alerts that  notify you when the amount of available space on a file system falls  below a specified threshold. Warning Alerts that are not critical, but represent potential problems. For  example, alerts that notify you when the status of a data collection job  is not normal. Informational Alerts that might not require any action to resolve and are primarily for  informational purposes. For example, alerts that are generated when a  new pool is added to a storage system In this example, we created three thresholds: Adjust the percentage levels to the required levels as needed. Keep in mind that the process  to extend storage might take its time (ordering process, installation, provisioning, and so on). The advantage of this way to setup an  Alert Policy  is, that you can add various IBM  FlashSystem 9100 (or even other storage subsystem such as the IBM FlashSystem 900) to  this customized alert. Figure 8-23 shows how to start creating a new Alert Policy which monitors the remaining free  capacity in the RAID Array. The customized Alert is not tied to the Data Reduction Pool, as it  works regardless of the pool type. GLYPH<SM590000> Critical (15% space in the RAID Array left) GLYPH<SM590000> Warning (20% space in the RAID Array left) GLYPH<SM590000> Information (30% space in the RAID Array left) In the following example we create a new Alert Policy by copying the existing one. You might  change an existing Alert Policy (in our example the Default Policy) as well. Keep in mind, a  storage subsystem can be active in only one Alert Policy.  Figure 8-23 Create new Alert Policy 304  IBM FlashSystem 9200 and 9100 Best Practices and Performance Guidelines