IBM TotalStorage DS6000 Series: Performance Monitoring and Tuning

Chapter 2. Hardware configuration planning 45

2.10.1 Host adapter configuration

When planning the configuration of the DS6000 host adapters that you will need, consider the

following:

1. Make a list of all the servers that will be connected to the DS6000, documenting the

amount of storage capacity they will be using, and the type of I/O workload they will

execute.

2. For the zSeries servers, document the type and number of channels you have available for

DS6000 connection. Channels can be only FICON. FICON Express2 surpasses former

FICON performance and connectivity capabilities, so it is the recommended option.

3. For the open systems servers you should also document the type and number of host bus

adapters (HBA) you have available for DS6000 connection.

4. For FICON and Fibre Channel connectivity you have the additional consideration of the

speed of the connecting ports. 2 Gbps should be the option for the servers’ HBAs and

SAN switches that connect to the 2 Gbps Fibre Channel/FICON host adapter ports of the

DS6000.

5. For all types of servers, the more DS6000 host adapters they connect to, the more I/O

bandwidth they will have available for their I/O processing. You must evaluate which is the

optimum number for each application/server, beyond which the significance of adding

more host attachment connections is negligible from a performance point of view.

Once the necessary information is ready, then Disk Magic can be run to evaluate the

alternatives for the DS6000 hardware configuration. As with other components of the DS6000

hardware configuration, consider that the DS6000

host adapters are not an isolated factor

when estimating the overall DS6000 performance. But instead, they must be considered

together with other important factors like the I/O workload characteristics, the cache size, the

disk drives capacity and speed, and the backend data layout and FC-AL loops.

2.10.2 FCP attachment

Fibre Channel is a technology standard that allows data to be transferred from one node to

another at high speeds (up to 200 MB/s) and greater distances (up to 10 km).

It is the very rich connectivity options of the Fibre Channel technology that has resulted in the

Storage Area Network (SAN) implementations. The limitations seen on SCSI in terms of

distance, performance, addressability, and connectivity are overcome with Fibre Channel and

a SAN.

46 IBM TotalStorage DS6000 Series: Performance Monitoring and Tuning

Figure 2-24 Fibre Channel/FICON host adapters - FCP attachment

The DS6000 with its Fibre Channel/FICON host adapters provides Fibre Channel Protocol

(FCP, which is SCSI traffic on a serial fiber implementation) interface, for attachment to open

systems that use Fibre Channel adapters for their connectivity.

The DS6000 supports up to 8 host ports, which allows for a maximum of 8 FCP ports per

DS6000. Each Fibre Channel/FICON host port provides one port with an LC connector type.

There are cable options that can be ordered with the DS6000 to enable connection of the

adapter port to an existing cable infrastructure.

As SANs migrate to 2 Gbps technology, your storage should be able to exploit this bandwidth.

The DS6000 Fibre Channel/FICON ports operate at up to 2 Gbps. The adapter

auto-negotiates to either 2 Gbps or 1 Gbps link speed, and will operate at 1 Gbps unless both

ends of the link support 2 Gbps operation.

There are two types of host adapter ports you can select:

Longwave or shortwave. With the

longwave laser, you can connect nodes at distances of up to 10 km (non-repeated). With the

shortwave laser, you can connect at distances of up to 300 meters. The distances can be

extended if using a SAN fabric.

When equipped with the Fibre Channel/FICON host ports, these ports can participate in three

types of Fibre Channel topology by setting the port topology:

򐂰 Port topology: SCSI-FCP

– Fibre channel topology: Point-to-point or Switched fabric

򐂰 Port topology: FC-AL

– Fibre channel topology: Arbitrated loop

Fibre Channel distances

The type of DS6000 Fibre Channel/FICON host port, shortwave or longwave, and the

physical characteristics of the fiber used for the link, will determine the maximum distances for

connecting nodes to the DS6000.

Note: The Fibre Channel/FICON host port supports both FICON or FCP, but not

simultaneously; the protocol to be used is configurable on a port-by-port basis.

intel

UNIX

iSeries

SAN Switch

SAN Switch

FCP attachment

•Up to 8 FCP ports per DS6800

•One port with an LC connector type

•Long wave or short wave option

•Up to 200 MB/sec full duplex

•Up to 10 km distance with long

wave and 300m short wave

•Fibre Channel Protocol (FCP)

•Supports switched fabric

•Fully participates in Storage Area

Networks (SANs)

•LUN masking