Snapshots are read-only, point-in-time copies of data in a volume, volume group, virtual machine (VM), or file system. In Oracle environments, snapshots are commonly used to create copies of databases for use with new applications or for development and testing of existing databases applications. The PowerStore T can also take snapshots of volumes that are used for file systems (SMB and NFS) and data for other applications that use block storage.
The PowerStore administrator can create write-ordered consistent and application consistent snapshots even for I/O consistency-critical applications like Oracle RAC. With write-ordered snapshots, the array creates a copy of the volumes in which all the writes are committed in the exact order they were submitted. This ensures that the database or application can be recovered and repurposed. With write-ordered consistent snapshots, no database or application recovery is required.
PowerStore T also provides the option to specify a read/write thin clone for application access when you create a copy of the database. You can update and modify both the original source database and the thin clone of the database in isolation. Even if the original source database is removed, the thin clone is unaffected and the business can continue using the cloned database. With thin clones, the business can establish hierarchical snapshot copies to preserve data in different states over time.
Both snapshots and thin clones can be used to refresh a modified storage resource. The process starts with removing the existing data. For example, you might want to take a snapshot of the data or database before removing it as a backup. If the original data must be recovered, it is easy to retrieve it from the backup snapshot. The refresh operation completes when all data has been copied. Refreshing a database from array-based copies enables activities like incremental testing or destructive tests common in software test/dev and many other scenarios. Both snapshots and thin clones benefit from data reduction, which saves substantial space on PowerStore T systems.
We configured all the volume groups with thin provisioning for the validation tests. We did not see any performance issues, which means that Oracle databases can safely use thin-provisioned volumes.