Technical data

A-2 Fabric OS Administrator’s Guide
Publication Number: 53-0000518-09
Impact of Changing the Fabric PID Format
A
• core
The default for SilkWorm 200E, 3016, 3250, 3850, 3900, 4012, and 4100 switches and SilkWorm
12000, 24000, and 48000 directors, this is the recommended format for Brocade switches and
fabrics. It uses the entire 8-bit address space and directly uses the port number as the area_ID. It
supports up to 256 ports per switch.
• extended edge
This format generates the same PID for a port on switches with 16 ports or less as would native PID
format, but it also supports up to 256 ports per domain. It should be used only in cases where you
cannot upgrade devices to dynamic PID binding and you absolutely cannot reboot your servers.
Extended edge PID is supported in Fabric OS v2.6.2 and later, v3.1.2 and later, and v4.2.0 and later.
In addition to the PID formats list here, Interoperability mode supports additional PID formats that are
not discussed in this guide.
Impact of Changing the Fabric PID Format
If your fabric contains switches that use Native PID, it is recommended that you change the format to
Core PID before you add the new, higher port count switches and directors. Also, it is recommended
that you use Core PID when upgrading the Fabric OS version on 2000 and 3000 series switches.
Depending on your situation, the PID change might or might not entail fabric downtime:
• If you are running dual-fabrics with multipathing software, you can update one fabric at a time
without disrupting traffic. Move all traffic onto one fabric in the SAN and update the other fabric.
Then move the traffic onto the updated fabric, and update the final fabric.
• Without dual-fabrics, stopping traffic is highly recommended. This is the case for many routine
maintenance situations, so dual-fabrics are always recommended for uptime-sensitive
environments. If your fabric contains devices that employ static PID binding, or you do not have
dual-fabrics, you must schedule downtime for the SAN to change the PID format.
You can find more details on the impact of PID changes in the following publications, which are
available on the Brocade partner Web site. If you do not have access to this site, ask your support
provider for these documents:
• Brocade SilkWorm Design, Deployment, and Management Guide (Publication Number: 53-
0000366)
• Brocade SAN Migration Guide (Publication Number: 53-0000360)
The following sections describe various impacts of PID format changes in greater detail.
Host Reboots
In some Fibre Channel SAN environments, storage devices and host servers are bound to the host
operating system by their PIDs (called their Fibre Channel addresses). In these environments, the hosts
and target HBAs in a SAN need to know the full 24-bit PIDs of the hosts and targets they are
communicating with, but they do not care how the PIDs are determined. But, if a storage device PID is
changed, the host must reestablish a new binding, which requires the host to be rebooted.