White Papers

SC Series array and Oracle storage management
70 Dell EMC SC Series: Oracle Best Practices | CML1114
6 SC Series array and Oracle storage management
Two Oracle features to consider for managing disks are Oracle Managed Files and ASM, a feature introduced
with Oracle 10g. Without these features, a database administrator must manage database files in native file
systems or as raw devices. This could lead to managing hundreds or even thousands of files. Oracle
Managed Files simplifies the administration of a database by providing functionality to automatically create
and manage files. ASM provides additional functionality for managing not only files but also the disks. ASM
handles the tasks of striping and providing disk redundancy at the operating system level, including
rebalancing the database files when new disks are added or removed from the system. The use of dynamic
multipath I/O combined with ASM and SC Series arrays yields high availability and performance for a
database server. ASM is the recommended and the preferred storage solution of Oracle.
When preparing disks for ASM, several different storage resource can be used:
• Logical unit numbers (LUNs)
LUNs are presented to the Linux server by SC series storage. Oracle recommends that hardware
RAID functionality is used within a LUN.
• Entire raw disk or partition of the raw disk
A disk partition can be the entire disk or part of the disk. However, the partition used by ASM cannot
be the partition that contains the partition table because Oracle would overwrite the partition table.
With SC series storage, raw disk or partitions of raw disk are created from LUNs.
• Logical volumes (LVM)
LVMs are typically used in less complicated environments and are mapped to a LUN or used raw disk
or partitions of a raw disk. As stated in Oracle’s ASM administrator’s guide, Oracle does not
recommend LVMs because they create duplication of functionality, and adds a layer of complexity
that is unnecessary with Oracle ASM. Also, Oracle does not recommend using LVMs for mirroring as
ASM provides mirroring. Since LVMs are not recommended by Oracle, they are not covered in this
document.
• NFS files
ASM disk groups for database files can be created from NFS and Oracle Direct NFS (dNFS). NFS or
dNFS files are not supported for Oracle Clusterware files. NFS files are available with the Dell EMC
FS8600 and FS7600 NAS appliances and are not covered in this document. See the document
Running Oracle over NFS with FS8600 scale-out file system on Dell TechCenter for additional
information.
6.1 ASM
After SC volumes are presented to a SC server object, the corresponding physical server can discover the
volumes as devices and condition them if necessary. ASM can then be used to define pools of storage from
these devices. These storage pools are called ASM disk groups and are comparable to LVM volume groups.
Once a disk group is created, the Oracle kernel manages naming and placement of the database files in the
disk group. ASM administrators can change the storage allocation (adding or removing disks) in disk groups
with SQL commands create diskgroup, alter diskgroup, and drop diskgroup. ASM
administrators can also manage disk groups with Oracle Enterprise Manager (EM), ASM command-line utility
(asmcmd), ASM Configuration Assistant (asmca), and Database Configuration Assistant (dbca).