Using the appropriate hardware, operating system, or database features can improve the downtime security of a
database instance.If you want to ensure a high level of security, we recommend the use of RAID-5 or RAID-1 configurations for the
system devspace and the data devspaces. A failure and the exchange of a disk does not impair database operation if the RAID system can carry out a restore process.Every devspace category should be stored on a different disk.
In a productive system, the log devspaces should always be mirrored for security reasons. The DUAL
log mode of the SAP DB database system can be used to this end. If the log entries are mirrored using other available hardware or software tools, then the SINGLE log mode can be used.You should not use RAID-5 configurations for the log devspaces. RAID-5 systems do not allow full mirroring. Because the database instance writes log entries sequentially, this can lead to a loss in performance.
In a productive system, never use the DEMO log mode, even when you are using RAID systems.
If you want to mirror the system devspace or the data devspaces, we recommend that you use RAID-1 configurations.
When using fault-tolerant hardware, it is best to only use the same type of hardware when you want to extend the capacity. For example, RAID-5 systems should only be extended using RAID-5 systems and mirroring disks with mirroring disks.
UNIX: In a productive system, data devspaces and log devspaces should be used in conjunction with raw devices. In the event of a system crash, raw devices are extremely secure.