This topic discusses iSeries™ storage management methods.
When Linux® is running on the Integrated xSeries® hardware, it uses a portion of the iSeries disk capacity. For this reason, the administration of a Linux server’s disk storage has both an i5/OS™ component and a Linux component. The i5/OS component is used to create and link a chunk of storage to the Linux server. The storage management function of i5/OS relieves the Linux server from the responsibility of providing physical device support. Therefore, many of the common disk administration tasks encountered in stand-alone PC servers (disk drivers, addressing, configuration and protection) are eliminated when you use an integrated Linux server. The Linux component of disk storage administration is used to perform the remainder of the disk administration tasks, including formatting and partitioning. These tasks are performed on an integrated Linux server in exactly the same way as they are on a stand-alone Linux server.
The key to understanding how disk storage is allocated to integrated Linux and Windows® servers is an understanding of how i5/OS storage management works on the iSeries. The heart of storage management on the iSeries is a technology called single-level storage. Single-level storage is a revolutionary storage management architecture that not only gives the iSeries outstanding disk I/O performance, but greatly reduces the amount of administration required.
The major features of single-level storage are:
The management of physical disk drives is implemented in the Systems Licensed Internal Code (SLIC), which is similar in concept to the BIOS on a PC.
By default, the operating system and applications see only a single large pool of virtual storage (called the System Auxiliary Storage Pool or system ASP) rather than physical drives. Therefore, the management of physical storage is hidden from the user.
To increase the size of the pool, simply add disk drives to the iSeries system and they automatically become part of the system ASP. Note that under some circumstances you might wish to create additional storage pools that are called user ASPs and independent ASPs.
Instead of an object being stored on a single physical disk drive, single-level storage scatters objects across all physical drives, transparently to the user.
iSeries disk management supports fully parallel disk I/O, which provides outstanding disk I/O performance because each object on the system is accessible by multiple disk arms concurrently.
There is no need to be concerned about particular disk drives filling up, or moving data from one disk to another to improve performance because all data management is taken care of by SLIC. Therefore, iSeries does not require a Database Administrator. SLIC also ensures that there is no disk fragmentation.
Memory and disk on iSeries form a single 64-bit address space.
A single address space enables objects to be accessed by name rather than hardware address, which provides additional integrity and reliability.