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There are several considerations and components that make up a SAN solution with IBM i. These include selecting the right fibre channel adapter, SAN switches and also the version of the operating system to benefit from connectivity to IBM System Storage® DS series, IBM System Storage Enterprise Tape Libraries, and IBM System Storage Ultrium (LTO) Tape devices.
POWER6 and IBM i 6.1 (i5/OS V6R1) have made significant improvements in connectivity and performance of SAN attach subsystems.
The new Fibre Channel controllers 5749 (PCI-X), 5774 (PCIe) and, 5735 (PCIe) have the following enhancements:
- Connectivity:
- The controllers are Smart IOAs so an IOP is no longer required. This improves the number of ports per slot by 2X.
- These controllers have 2 ports , a 2X improvement in number of ports per slot.
- The number of LUNs (Logical Unit Number) supported for disk attach is 64, a 2X improvement in number of LUNs per port.
- The combination of these improvement give a 4X improvement in number of ports per I/O slot and a 8X improvement in the number of LUNs per I/O slot. A LUN is how a single storage entity is defined on the SAN to the IBM i storage management (looks like a disk drive).
- The #5749 is supported on POWER5 systems, with IBM i 6.1.
- The Fibre channel controllers (#5749, #5774 and #5735) will allow IPL directly from SAN attached tape (alternate IPL) but only when used on POWER6 systems.
- Performance:
- The new controllers have hardware enhancements that reduce data transfer overhead times and better utilize bus bandwidth.
- The removal of the requirement for the IOP reduces the overall overhead of the subsystem.
- These enhancements enable SAN attached disk to approach integrated storage performance levels. Performance is very dependant on workloads and environments, work with your technical sales rep to understand how your environment will perform.
- Copy Services (Flash Copy, Remote Mirroring):
- o DS8000 and DS6000 have integrated Copy Services capabilities. For details on these capabilities refer to:
- DS4700, DS4800, DS5100 and DS5300 have a unique set of copy services capabilities that differ from DS8000 and DS6000. For an understanding of how these work in the IBM i environment refer to the Open Storage Read Me (PDF, 772KB) document.
- DS3400 has no copy services capability at this time
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IBM i 6.1 capabilities:
- IBM i 6.1, leveraging the capabilities of a Virtual I/O Server (VIOS), enables the attachment of the IBM System Storage DS5100, DS5300, DS4800, DS4700 and DS3400 SAN storage devices, plus the SVC appliance. This provides additional performance and price points for those considering SAN attached disk.
- With i 6.1 IBM i can run as a client of another partition. VIOS runs in a separate partition and is transparent to the Storage Manager in the IBM i client partition.
- DS5300, DS5100, DS4700, DS4800, DS3400 and SVC attach through VIOS using AIX Fibre Channel adapters #5716, #5758, #5759, #5773, #5774 and #5735.
- When purchasing these midrange storage products it is recommended that the user select the Fibre Channel disk drives option over the SATA disk drives, to optimize performance. If minimal cost is the main concern in the purchase decision, then SATA drives can be considered.
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