关注Brocade 8Gb SAN交换机的Fill Words参数

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最近学习IBM V7000存储，偶然在红皮书《Implementing the IBM Storwize V7000 V6.3》（sg247938）上看到了以下内容：

Connectivity issues: If you have any connectivity issues between IBM Storwize

V7000 ports and Brocade SAN Switches or Directors at 8 Gbps, see

http://www-01.ibm.com/support/docview.wss?rs=591&uid=ssg1S1003699 for the

correct setting of the fillword port config parameter in the Brocade operating system.

这里面提到了SAN交换机端口的一个参数fillword。大体了解一下这个参数，也不知道理解的是否正确。

Fill-Word是一种primitive signal，用于在两个端口间传输状态消息，在端口没有用户数据传输的时候，端口就会发送fillword，用来保持端口间的位和字同步。

Fillwords主要有三种，分别为IDLE、ARB（F0）和ARB（FF）。

在1G/2G/4G标准中，链接初始化和发送fillword，Brocade SAN交换机都用IDLE primitive signal。随着端口速率升级到8Gbps，时钟速度的增加，这种IDLE的模式会造成高消耗，影响了端口的链接问题。为了解决这个问题，在FC-PI-4和FC-FS-3标准中使用了ARB（FF）这种模式作为8G FC的fillword。

但是可惜的是，有些8Gbps的设备在ARB/ARB或IDLE/ARB模式下不能与8G FC交换机建立起正常的链接，因此存储厂商和交换机厂商都有针对性的建议。

IBM针对这种情况给了类似的一些tips

http://www-947.ibm.com/support/entry/portal/docdisplay?brand=5000028&lndocid=MIGR-5083089

http://www-01.ibm.com/support/docview.wss?rs=591&uid=ssg1S1003699

HP也有这方面的说明：

http://h20565.www2.hp.com/portal/site/hpsc/template.PAGE/public/psi/troubleshootDisplay/?sp4ts.oid=3984629&spf_p.tpst=psiContentDisplay&spf_p.prp_psiContentDisplay=wsrp-navigationalState%3DdocId%253Demr_na-c02619780%257CdocLocale%253Dzh_CN&javax.portlet.begCacheTok=com.vignette.cachetoken&javax.portlet.endCacheTok=com.vignette.cachetoken

Brocade公司也有类似的文档，例如 FOS 8G Link Init Fillword Behavior v1.pdf

总结这些内容如下：

1. 在Brocade SAN交换机FOS版本为6.2.x的时候，使用IDLE也就是mode 0。

查看当前端口的工作模式，假设查看端口14，portCfgShow <PortNumber>

>portcfgshow 14

Area Number: 14

Speed Level: AUTO(HW)

Fill Word: 1(Arbff-Arbff)

修改为mode 0，portCfgFillWord <PortNumber> <Mode>

>portcfgfillword 14 0

portcfgshow 14

Area Number: 14

Speed Level: AUTO(HW)

Fill Word: 0(Idle-Idle)

2. 在FOS版本6.3.1或以上时，Brocade提供了4种fillword模式，如下：

MODE	MEANING
Mode 0	Use IDLE in link init and IDLE as fill word
Mode 1	Use ARB in link init and ARB as fill word
Mode 2	Use IDLE in link init and ARB as fill word
Mode 3	Try mode 1 first; if it fails then try mode 2

在8Gbps接口的时候，选择使用Mode 3是合理的一个参数，至少Brocade是这么建议的，这种模式更灵活能够适应大部分环境，与大量设备相兼容，如果还是有问题，那就需要联系存储厂商了。

> portcfgshow 14

Area Number: 14

Speed Level: AUTO(HW)

Fill Word: 3(A-A then SW I-A)

需要注意的是，该参数的修改都会引起端口通讯中断，所以要注意安全哦。

转:danny0571@gmail.com

Abstract

Starting with FOS levels v6.2.0, v6.2.0a & v6.2.0b, Brocade introduced arbff-arbff as the new default fillword setting. This caused problems with any connected 8Gb SVC ports and these levels are unsupported for use with SVC, Storwize V7000 or Storwize V7000 Unified.
In 6.2.0c Brocade reintroduced idle-idle as the default fillword and the also added the ability to change the fillword setting from the default of idle-idle to arbff-arbff using the portcfgfillword command. For levels between 6.2.0c and 6.3.1 the setting for SVC, Storwize V7000 and Storwize V7000 Unified should remain at default mode 0.
From FOS v6.3.1a onwards Brocade added two new fillword modes with mode 3 being the new preferred mode which works with all 8Gb devices. This is the recommended setting for SVC, Storwize V7000 and Storwize V7000 Unified.

Content

This affects the following IBM/Brocade switches:

IBM Model	Brocade Model
2498-B24	Brocade 300
2498-B40	Brocade 5100
2498-B80	Brocade 5300
2499-192	Brocade DCX-4S
2499-384	Brocade DCX

Recommendations
The recommended solution is to use FOS v6.3.1a or above and ensure all 8Gb SVC, Storwize V7000 or Storwize V7000 Unified ports are set to use fillword mode 3.

Note
This only affects 8Gbps switch ports with SVC, Storwize V7000 and Storwize V7000 Unified devices connecting at 8Gb port speeds, if using 4Gb or below with SVC, Storwize V7000 or Storwize V7000 Unified the fillword settings can still be set to 3 and this mode will be used if and when the fabric or SVC, Storwize V7000 or Storwize V7000 Unified are upgraded to 8Gbps.

Instructions
1) To check the fillword mode setting for a particular port use the portcfgshow command:

example:
IBM_2499_192:FID128:admin> portcfgshow 1/0
Area Number: 0
Speed Level: AUTO(HW)
Fill Word: 3(A-A then SW I-A)
AL_PA Offset 13: OFF
------------------- cut -------------------

2) To change the fillword mode setting for a port use the portcfgfillword command:

example (setting fillword mode 3 on blade 1 port 0):
portCfgFillWord 1/0 3

交换机

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