Posts Tagged ‘fibre channel’

Merging Brocade Fabrics

February 23, 2016

fibreRecently I needed to merge two pairs of Brocade fibre channel fabrics for one of the customers. When I was doing a bit of my own research I realised that there is very scarce information on how to do that on the Interwebs. There were a few community posts on the Brocade forums, but there seemed to be some confusion around how zoning should be configured to let the switches merge successfully. I thought I would fill the gap with this post and share my own experience.

Prerequisites

First, make sure you have the right transceivers. Short wave 8Gb FC transceivers are limited to 190m when using OM4 fibre. If you need to connect switches over a longer distance, use long wave SFP+ modules, which have maximum distance of 10km.

Second, change the default switch Domain IDs. All switches within the same fabric must have unique IDs. By default Brocade switches come with the Domain ID set to 1. If you’re merging two redundant fabrics, make sure that the second pair of the switches have Domain IDs set to 2.

Third, verify that the switches you’re interconnecting have compatible zoning configuration. Brocade is very specific on how zoning should be configured for two fabrics to merge. There are at least nine different scenarios, but we’ll touch only on three most common ones. If you want to get more details, refer to the Brocade Fabric OS Administrator’s Guide and specifically the section called “Zone merging scenarios”.

Zone merging scenarios

Scenario 1: Switch A does not have a defined configuration. Switch B has a defined configuration.

This is the most straightforward scenario when you are adding a brand new Switch A to an existing fabric. As a result of the merge configuration from the Switch B propagates to the switch A.

Scenario 2: Switch A and Switch B have different defined configurations. Switch B has an effective configuration.

This is the scenario where you have two individual fabrics with their own set of aliases, zones and defined configurations. There is a catch here. If you want to merge such fabrics, you MUST have unique set of aliases, zones and configurations on each fabric. If this requirement is not met, fabrics won’t merge and you will end up with two segmented fabrics because of the zoning conflict. You also MUST disable effective zoning configuration on Switch A.

Outage is not required, because typically you have two redundant fabrics – fabric A and B in each location. And you can do one switch at a time. If you are still concerned, implement Scenario 3.

Scenario 3: Switch A and Switch B have the same defined and effective configuration.

This is the easiest path and is what Brocade calls a “clean merge”. Under this scenario you will have to recreate the same configs on both fabrics. That means you MUST have completely identical aliases, zones and configs on Switch A and Switch B.

This is the easiest and least disruptive path if you are worried that disabling effective configuration on the switches may cause issues.

Real world scenario

In my case I went with scenario 2 for two reasons: one – it was a DR site where I could temporarily bring down both fabrics and two – I didn’t need to manually add aliases/zones/configs to the switches as I would have to in scenario 3. Once fabrics are merged, zones from Switch B propagate to Switch A and you can simply combine them in one zone in the GUI, which is just a few mouse clicks.

site_topology

Here is the step by step process. First step is to change Domain IDs on the second pair of switches. You can do that both from GUI and CLI. Bear in mind that even if you’ve picked scenario 3 as the least disruptive approach for merging zones, changing Domain IDs will still be disruptive. Because switch has to be disabled before making the change.

From the Web Tools go to Switch Administration, disable the switch in the Switch Status section, type in the new Domain ID and re-enable the switch:

domain_id

If you want to take the CLI path, run the following. Switch will ask you a series of questions. You can accept all defaults, except for the Domain field:

> switchdisable
> configure
> switchenable
> fabricshow

Next disable the effective configuration on the Switch A either from GUI or CLI:

> cfgdisable
> cfgactvshow

At this point you can interconnect the switches and you should see the following log entry on Switch A:

The effective configuration has changed to SWITCHB_CONFIG

The fabrics are now merged an you should see both switches under the Web Tools. If you see the switch in the Segmented Switches section, it means that something went wrong:

merged_fabrics

Clean up steps

Once the fabrics are merged you will see all zones in the Zone Admin interface, however, the effective configuration will be configuration from the Switch B. You will need to create a new configuration which combines all zones to enable connectivity between the devices connected to the Switch A.

From the operational perspective you can now manage zoning on either of the switches and when you save or enable a configuration it will propagate to all switches in the fabric automatically.

If you have redundant fabrics, which you normally do, repeat the steps for the second pair of switches.

Conclusion

Steps described in this post are for a basic switch setup. If you have a non-standard switch configuration or using some of the advanced features, make sure to check “Zone Merging” section in the Fabric OS Administrator’s Guide for any additional considerations.

Let me know if this was helpful.

 

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Brocade 300 Firmware Upgrade

December 14, 2015

In my previous post Brocade 300 Initial Setup I briefly went through the firmware upgrade process, which is a part of every new switch installation. Make sure to check the post out for instructions on how to install a FTP server. You will need it to upload firmware to the switch.

I intentionally didn’t go into all details of firmware upgrade in my previous post, as it’s not necessary for a green field install. For a production switch the process is different. The reason is, if you’re upgrading to a Fabric OS version which is two or more versions apart from the current switch firmware revision, it will be disruptive and take the FC ports offline. Which is fine for a new deployment, but not ideal for production. 

Disruptive and Non-Disruptive Upgrades

Brocade Fabric OS major firmware release versions are 6.3.x, 6.4.x, 7.0.x, 7.1.x, 7.2.x, etc. For a NDU the rule of thumb is to apply all major releases consecutively. For example, if my production FC switch is running FOS version 6.3.2b and I want to upgrade to version 7.2.1d, which is the latest recommended version for my hardware platform, then I’ll have to upgrade from 6.3.2b to 6.4.x to 7.0.x to 7.1.x and finally to 7.2.1d.

First and foremost save the current switch config and make a config backup via FTP (give write permissions to your FTP user’s home folder). Don’t underestimate this step. The last thing you want to do is to recreate all zoning if switch loses config during the upgrade:

> cfgSave
> configUpload

configUpload

In case you need to restore, you can run the following command to download the backed up config back to the switch:

> configDownload

Next step is to install every firmware revision up to the desired major release (-s key is not required):

> firmwaredownload

brocade_ndu.JPG

Brocade switch has two firmware partitions – primary and secondary. Primary is the partition the switch boots from. And the secondary partition is used for firmware upgrades.

After each upgrade switch does a warm reboot. All FC ports stay up and switch continues to forward FC frames with no disruption to FC traffic. To accomplish that, switch uses the secondary partition to upload the new firmware to and then quickly swap them without disrupting FC switching.

At a high level the upgrade process goes as follows:

  • The Fabric OS downloads the firmware to the secondary partition.
  • The system performs a high availability reboot (haReboot). After the haReboot, the former secondary partition is the primary partition.
  • The system replicates the firmware from the primary to the secondary partition.

Each upgrade may take up to 30 minutes to complete, but in my experience it doesn’t take more than 10 minutes. Once the first switch is upgraded, log back in and check the firmware version. And you will see how secondary partition has now become primary and firmware is uploaded to the secondary partition.

brocade_upgrade3

As a last step, check that FC paths on all hosts are active and then move on to the second switch. The steps are exactly the same for each upgrade.

Firmware Upload and Commit

Under normal circumstances when you run the firmwareDownload command, switch does the whole upgrade in an automated fashion. After the upgrade is finished you end up with both primary and secondary partitions on the same firmware version. But if you’re a large enterprise, you may want to test the firmware first and have an option to roll-back.

To accomplish that you can use -s key and disable auto-commit:

single_mode

Switch will upload the firmware to the secondary partition, switch secondary and primary partitions after a reboot, but won’t replicate the firmware to the secondary partition. You can use the following command to restore firmware back to the previous version:

> firmwareRestore

Or if you’re happy with the firmware, commit it to the secondary partition:

>  firmwareCommit

The only caveat here, a non-disruptive upgrade is not supported in this scenario. When switch reboots, it’ll be disruptive to FC traffic.

Important Notes

When downloading firmware for your switch, make sure to use switch’s vendor web-site. EMC Connectrix DS-300B, Brocade 300 and IBM SAN24B-4 are essentially the same switch, but firmware and supported versions for each OEM vendor may slightly vary. Here are the links where you can get FC switch firmware for some of the vendors:

  • EMC: sign in to http://support.emc.com > find your switch model under the product section and go to downloads
  • Brocade: sign in to http://www.brocade.com > go to Downloads section > enter FOS in the search field
  • Dell: http://www.brocadeassist.com/dellsoftware/public/DELLAssist includes a subset of Fabric OS versions, which are tested and approved by Dell
  • IBM: http://ibm.brocadeassist.com/public/FabricOSv6xRelease and http://ibm.brocadeassist.com/public/FabricOSv7xRelease are the links where you can download FOS for IBM switches. You can also go to http://support.ibm.com, search for the switch in the Product Finder and find FOS under the “Downloads (drivers, firmware, PTFs)” section

References

VNX/VNXe array negotiates FC port as L-Port

March 23, 2015

Hit an issue today where VNXe array FC ports negotiate to L-port instead of F-port when Fill Word is set to Mode 3 (ARB/ARB then IDLE/ARB). Result – loss of connectivity on the affected link.

vnx_lport

Recommended FC Fill Word for VNX/VNXe arrays is Mode 3. Generally it’s a good idea to set them according to best practice as part of each installation. Apparently, when changing Fill Word from legacy Mode 0 (IDLE/IDLE) to Mode 3 (ARB/ARB then IDLE/ARB) array might negotiate as L-port and FC path goes down.

Solution is to statically configure port as F-port in port settings.

vnx_lport_sol

Environment:

  • Dell M5424 8Gb Fibre Channel Switch: Brocade FOS v7.2.1b
  • EMC VNXe 3200: Block OE v3.1.1.4993502

Random DC pictures

January 19, 2012

Several pictures of server room hardware with no particular topic.

Click pictures to enlarge.

10kVA APC UPS.

UPS’s Network Management Card (NMC) (with temperature sensor) connected to LAN.

Here you can see battery extenders (white plugs). They allow UPS to support 5kVA of load for 30 mins.

Two Dell PowerEdge 1950 server with 8 cores and 16GB RAM each configured as VMware High Availability (HA) cluster.

Each server has 3 virtual LANs. Each virtual LAN has its own NIC which in its turn has multi-path connection to Cisco switch by two cables, 6 cables in total.

Two Cisco switches which maintain LAN connections for NetApp filers, Dell servers, Sun tape library and APC NMC card. Two switches are tied together by optic cable. Uplink is a 2Gb/s trunk.

HP rack with 9 HP ProLiant servers, HP autoloader and MSA 1500 storage.

HP autoloader with 8 cartridges.

HP MSA 1500 storage which is completely FC.

Hellova cables.