Integrated direct attach storage

IBM i offers a sophisticated, high performance, automated, integrated storage solution. IBM i Integrated Direct Attach Storage offers high performance and large capacities.

Self-optimizing and self-configuring storage automation is provided by including automatic protection and distribution of data (data spreading) across disk pools offering excellent performance and minimal operator involvement. Storage management is further simplified by extensive graphical interfaces provided by the IBM i Navigator. Integrated IBM i storage offers RAID-5 or RAID 6 data protection as well as complete data and I/O path storage redundancy (bus, adapter, cache, device) which can be provided via Disk Mirroring (similar to RAID-10).
Highlights of the high performance PCI-X integrated disk storage adapter for SAS:

• Up to 1.5 GB of write cache and 1.6 GB of Read Cache per controller with compression.
• The controller (#5904/5906/5908) attaches up to 5 (5886) 12 EXPS SAS storage drawers (12 SAS disk drives/box) .  This adapter is PCI-X and can be housed in a HSL (5790, 5094, 5294, 5096, 5296, 0595, 5095), or a 12X (5796, 5797, 5798) I/O drawer.
• With V5R4 the controllers no longer require any I/O Processor(IOP), improving PCI-X slot availability.
• The controller has Auxiliary Write Cache to maximize protection of the data in cache.

Highlights of the PCI-e integrated Storage Adapter for SAS:

• Up to 380MB of write cache. The adapters use a shared cache technology. This requires that they be installed in pairs. The adapter mirrors the write cache information between the paired adapters.
• With the paired adapter set, there is the capability to set up two adapters in the same SAS loop. Each adapter is assigned a primary set of disks in the loop. If one adapter fails the remaining adapter will assume control of all the disks in the loop and continue to run. Write caching is disabled when only one adapter in the pair is operational.
• The PCIe SAS controller (#5903) can be housed in the Power Systems main I/O complex or in the PCIe 12X I/O drawers (#5802/5803 with disks or #5877/5973 without integrated disks). The adapter pair can control SAS disk drives or SSDs in the system complex, in the PCIe 12X I/O drawer or in the standalone EXP12 Storage Drawer (#5886). This controller can attach up to 4 EXP12 Storage Drawers.

Transition from SCSI to SAS (Serial Attached SCSI)

With the introduction of POWER6, Power Server is moving from the SCSI based disk technology to a SAS based disk technology. SAS works in serial loop configuration, giving it performance and availability advantages over the older SCSI technology.

All of the POWER6 and new POWER7 System units will house only SAS disk drives. The 12X I/O drawers (#5802 and #5803) only support SAS disk drives.

• ALL SCSI Drives have been withdrawn from sales as of August 2009
• SUPPORT FOR SCSI DRIVES WILL CONTINUE BEYOND 2010

New Solid State Disk (SSD) technology

New 69 GB Solid State Drives (SSD) provide for storage and retrieval of data which is much, much, MUCH faster than spinning disk drives. These 69.7 GB drives allow you to leap over bottlenecks in disk drive technology. The root cause for disk's slower performance is waiting for the movement of the disk platter and the disk arm. SSD random reads/writes can occur in microseconds, not the milliseconds that it takes for spinning drives (also called Hard Disk Drives or HDD). The size of the I/O performance increase and resulting overall system performance increase will depend upon your configuration and applications.

SSD has more than just performance advantages. SSD has no moving parts increasing its reliability. SSD has no motor and needs far less electrical power or cooling than disk drives. And unlike HDD which are often run at less than 50% storage capacity to help maintain consistent performance, SSD can be run much closer to 100% storage capacity and still provide excellent performance.

The 69 GB SSD plugs into a standard SAS disk bay slot and is controlled by a SAS controller (5904, 5906, 5908). SSD is offered in two form factors, a 3.5-inch (#3587) and an SFF (#1909). The 3.5-inch SSD is used in the #5886 EXP 12S Disk Drawer and is controlled by the PCI-X 1.5GB Cache SAS RAID adapter. The SFF SSD is also used in Power 520/550 System base SFF slots and is controlled by the imbedded controller.