Specifications

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Summary of Best Practices for Storage Area Networks

with multiple ports will help prevent a single storage port from being the source or cause

a performance bottleneck due to high latency or outfight congestion.

One overall theme for SAN best practice guidelines is consistency, and this concept is

equally applicable to zone element naming conventions. A zone name should indicate

which devices are enabled to communicate by the specific zone along with enough info

to determine which fabric the zone can be found. At a minimum, the zone name should

provide information about the following items:

 Location

 Server

 Server port

 Storage resource

 Fabric

For example, the zone name “PilRd_SQL12_ed74_DS8K1_1132_A” denotes the data

center location (Pilgrim Road), the server (SQL12), which port on the server (ed74 -

which are the last 2 bytes of the server port’s WWPN), the storage system (DS8K1), the

storage port (1132 - DS8000 rack 1, IO bay 1, slot 3, port 2) and which fabric (A) within

the SAN environment.

Never mix tape and disk traffic on the same server Host Bus Adapter (HBA) port with

one or more zone definitions. This issue is a source of confusion for many

administrators due to a number of reasons. Most HBA vendors state that they support

mixing tape and disk traffic on the same port. Based on the collective experience of the

IBM SAN Central team, customer environments with tape and disk traffic on the same

HBA port will eventually experience problems.

Fibre channel is nothing more than a transport mechanism, and the bulk of the traffic is

SCSI. So consider this question: would you mix tape and disk devices on an older style

parallel SCSI controller bus? Most SCSI logical interfaces associated with an HBA port

will use optimized settings for either tape or disk. The unit of time for disk IO operations

is measured in milliseconds compared to seconds or even minutes for tape. Thus, it

should be obvious that the expected timing parameters used for one type of traffic is

radically different for the other traffic type.

Keep test and production environments separated by zoning. This suggested best

practice statement is due to the high risk of disruptions that typically occur in test and