Fcp Partner Path Misconfigured

8/11/2019 Fcp Partner Path Misconfigured

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Answer

AutoSupport message: FCP PARTNER PATH MISCONFIGURED

Syslog and EMS messages

[hostname: scsitarget.partnerPath.misconfigured:error]: FCP Partner PathMisconfigured.[hostname: scsitarget.partnerPath.misconfigured:error]: FCP Partner PathMisconfigured - Host I/O access through a non-primary and non-optimal pathwas detected.

Terminology

Partner Path: Any path to LUNs that utilizes the partner node to access a LUN hosted by

the local node. The LUNs are in an active-active cluster.

Non-primary path: Synonymous with partner path, proxy path and secondary path. All

are examples of a non-primary path.

FCP target port: The fibre channel interface that provides FCP service to hosts.

Virtual Target Interconnect (VTIC): The virtual FCP target interface seen in the initiator

group list. VTIC is used to indicate that the initiator has access to a secondary path.

Problem DescriptionNetApp active-active clustered storage controllers allow access to logical units (LUNs) through

FCP ports on both nodes of the cluster. Hosts should, under normal circumstances, only access

LUNs through ports on the cluster node which hosts the LUN. I/O paths that utilize the ports ofthe cluster node that host the LUN are referred to as primary paths or optimized paths. I/O paths

that utilize the partner cluster node are known as secondary paths, partner paths or non-optimized

paths. A LUN should only be accessed through the partner cluster node when the primary ports

are unavailable.

I/O access to LUNs using a secondary path indicates one or both of the following conditions: theprimary path(s) between host and storage controller have failed, or host MPIO software is not

configured correctly. These conditions indicate that the redundancy and performance of the SAN

has been compromised. Corrective action should be taken immediately to restore primary paths

to the storage controllers.

In some circumstances, this error may also be triggered by non-I/O activity such as MPIO path

management operations or host clustering software performing status checks to LUNs. If either

of these situations is determined to be responsible for triggering the error, steps may be taken todecrease this activity or specify custom thresholds for the trigger conditions. Beginning with

Data ONTAP 7.2.2, non-read and non-write operations will not trigger this error message.

FCP Partner Path Misconfigured errors may spuriously occur following storage controller boots,


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storage controller cluster takeover and giveback operations or host reboots. These instances of

the error are normal and are usually corrected once the host's MPIO software detects the changed

path status. These occurrences of the error may be ignored if they are not continuous. DataONTAP 7.2.2 and later releases have enhancements to prevent spurious triggers of this error

following storage controller boot or cluster takeover or giveback operation.

NetApp now recommends adjusting the thresholds that control the trigger for the FCP PartnerPath Misconfigured message to avoid spurious and unnecessary occurrences. Please issue the

following commands on both nodes of the storage controller cluster.

options lun.use_partner.cc.warn_limit 300options lun.use_partner.cc.bytes 2457600

The first option increases the time interval from 10 seconds to 300 seconds and the second option

increases the bytes transferred threshold from 512000 bytes to 2457600 bytes.

If the warning message continues after making these changes then please follow the stepsoutlined in the remainder of this document.

The following diagrams illustrate I/O access through a primary path and non-primary path.


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b. lun show -v (LUN CONFIGURATION)

c. igroup show -v (INITIATOR GROUPS)

3. Identify the primary storage controller FCP target ports available for access to the LUN:

a. fcp show cfmode (FCP CFMODE)

b. fcp show adapters (FCP TARGET ADAPTERS)

4.

Verify the host initiator connectivity to primary FCP target ports and the host MPIOsoftware configuration.

5. Verify use of the partner path has ceased from both cluster nodes:sysstat -b 1

Procedure and Example Data

1. Identify the LUNs being accessed through the partner node's FCP target port as well as

the type of operation.

The error threshold may be triggered by either the number of kilobytes read and written

or the number of non-read and non-write operations performed. Examples of non-readand non-write SCSI operations are Inquiry, Persistent Reserve, Report LUNS, and Test

Unit Ready. Data ONTAP 7.2.2 and later releases will not trigger this warning for non-read and non-write operations.

The LUN STATISTICS section of the Autosupport will display the read and writeoperations for both local and partner paths per LUN. This output may also be obtained

using the command lun stats -o. The counters may also be zeroed using the command

lun stats -zwhich is useful for determining how often the counters are increasing.

The output of lun statsmight show that no counters have exceeded the threshold. Inthis case, the LUNs that are being accessed by a partner path may reside on the partner

node. Once the affected LUNs have been identified, continue to Step 2 to locate theresponsible host.

Example of lun stats -ooutput from Autosupport:

===== LUN STATISTICS =====/vol/esx_luns/guest001.lun (32 minutes, 39 seconds)

Read (kbytes) Write (kbytes) Read Ops Write Ops OtherOps QFulls Partner Ops Partner KBytes

13510011357 12648494826 707504214932701251 251651 0 263445977 2123914089

In the example above, both Partner Ops and Partner Kbytes have exceeded the threshold

in the given time interval. The hosts accessing the LUN in this way should be identified

and the reasoning for the access evaluated. Possible solutions are to restrict access, ortune the host MPIO software so that it will not attempt access through the partner path.

2. Identify the host initiators that are performing the I/O through the partner path.

Using the LUNs identified in Step 1, locate the suspect initiators by cross-referencing the


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LUN configuration with the initiator group mapping. This information can be found in

the AutoSupport section titled LUN CONFIGURATION and by using the command lun

show -v. Once the LUN's initiator groups have been identified, the initiator WWPNs that

are members of the initiator group can be found in the Autosupport section INITIATOR

GROUPS and with the command igroup show -v.

Example oflun show -vand igroup show -vfrom the AutoSupport:

===== LUN CONFIGURATION =====/vol/esx_luns/guest001.lun 2.0t (2194459852800) (r/w, online,mapped)Comment:Serial#: XXXXXXXXXShare: noneSpace Reservation: enabledMultiprotocol Type: linuxMaps: igroupA=0 igroupB=0

===== INITIATOR GROUPS =====igroupA (FCP) (ostype: vmware):

21:00:00:e0:8b:92:da:ef (logged in on: 0a, vtic)igroupB (FCP) (ostype: vmware):

21:00:00:e0:8b:82:d0:09 (logged in on: 0c, vtic)

In this example, the LUN /vol/esx_luns/guest001.lun is mapped to two initiator groups,igroupA and igroupB. Each initiator group contains one WWPN. These WWPNs belong

to different ports which may be on the same host or on different hosts, depending on the

deployment. The WWPNs that were identified in the initiator groups comprise a list ofsuspect initiators that could be accessing the LUN through a non-primary path. This list

of suspect initiators will need to be checked in Step 4.

To reduce the suspect list, Data ONTAP 7.2.2 and later releases provide a list of initiatorsperforming I/O access using the partner path. This information can be found in the LUN

CONFIG CHECK section of the AutoSupport and the output of the command lun

config_check -A(Caution: The output of lun config_check -A is only valid whenincluded in AutoSupport). In addition to listing initiator access through the partner path,

lun config_check -vwill check and display a variety of other possiblemisconfigurations. Any issues presented in the output should be addressed before

proceeding.

Example of lun config_check -Afrom the AutoSupport:

===== LUN CONFIG CHECK =====

The following FCP Initiators are sending Read/Write i/o over theFCP Partner Paths during the last 15 secondsWWPN Partner's Port ops bytes21:00:00:e0:8b:25:0c:10 0c 34 1740821:00:00:e0:8b:25:03:66 0c 186 111769621:00:00:e0:8b:25:0c:18 0c 1618 1086668821:00:00:e0:8b:25:0b:b0 0c 1693 13290496


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In this example, four initiators are accessing LUNs through the partner path. Some

amount of operations are acceptable and normal for MPIO path management. The high

operation count and byte count initiators are the ones that must be examined forMPIO configuration issues.

3.

Identify the primary storage controller FC target ports available for access to the LUN.

In the active-active storage controller configuration, primary versus secondary ports will

depend on the cluster failover mode (cfmode) employed. For example, the single_image

cfmode allows each FC target port to be used for primary path access to LUNs hosted onthe local node and partner path access for LUNs hosted on the partner node. For

information about cfmode and port configurations, please see theData ONTAP Block

Access Management Guidefor your version of Data ONTAP..

The cfmode might be identified using the command fcp show cfmode. It can also belocated in the FCP CFMODE section of the AutoSupport.

===== FCP CFMODE =====fcp show cfmode: single_image

The FCP target ports can be displayed using the command fcp show adapterand in theAutoSupport section FCP TARGET ADAPTERS.

This example shows the target adapters when using the cfmode single_image. When

using single_image cfmode, either port may be used to access LUNs hosted on both thelocal and partner nodes.

> fcp show adaptersSlot: 0cDescription: Fibre Channel Target Adapter 0c (Dual-channel,QLogic 2322 (2362) rev. 3)Adapter Type: LocalStatus: ONLINEFC Nodename: 50:0a:09:80:86:17:c3:ac (500a09808617c3ac)FC Portname: 50:0a:09:81:96:17:c3:ac (500a09819617c3ac)

Slot: 0dDescription: Fibre Channel Target Adapter 0d (Dual-channel,QLogic 2322 (2362) rev. 3)Adapter Type: Local

Status: ONLINEFC Nodename: 50:0a:09:80:86:17:c3:ac (500a09808617c3ac)FC Portname: 50:0a:09:82:96:17:c3:ac (500a09829617c3ac)

Verify the host initiator connectivity to primary FCP target ports and the host MPIOsoftware configuration, using the suspect list generated in Step 2.

Once the primary and secondary FCP target ports have been identified, confirm that thehost initiators are logged in. Connectivity of host initiators to the fabric and FCP target
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ports can be checked from the host. While the storage controller is capable of

determining which initiators have been logged in, this information is not always current.

Only the host initiators are able to provide current login status information. Tools such asEmulex's HBAnywhere and QLogic's SANSurfer may be used to determine the state of

the initiators. If the initiator is no longer logged into the primary FCP target port, then the

fabric should be inspected for link failures or zone restrictions that would preventconnectivity to the FCP target ports.

The following articles provide detailed procedures to verify host initiator connectivity

and MPIO configuration for each host operating system:

1010434:How to verify HP-

UX fibre channel configurations with multipathing I/O (MPIO)

1011509:

How to Verify VMWare ESX 3.x Fibre Channel Configurations with Multipathing I/O (MPIO)

1011577:

How to Verify VMWare ESX 4.x Fibre Channel Configurations with Multipathing I/O (MPIO)

1012650:

How to verify Windows fibre channel configurations with multipathing I/O (MPIO)

1010943:How to verify Solaris fibre channel configurations with multipathing I/O (MPIO)

1010260:

How to verify Linux fibre channel configurations with multipathing I/O (MPIO)

1011508:How to verify AIX fibre channel configurations with multipathing I/O (MPIO)

1011507:

How to verify NetWare fibre channel configurations with multipathing I/O (MPIO)

3011171:How to verify VMware ESXi configurations with multipathing I/O

Verify use of the partner path has ceased from both cluster nodes.

The sysstat -b 1command might be used to monitor SAN-related summary performance

counters. The 'Partner' counter monitors I/O operations and data transfers that use the partner

path. Monitoring these counters is an effective method to verify that the source of partner path

traffic has been corrected. Be sure to check for partner path access from both cluster nodes as

partner path traffic could be entering the cluster from both nodes.

CPU FCP iSCSI Partner Total FCP kB/s iSCSI kB/s

Partner kB/s Disk kB/s CP CP Diskin out in out in out r

ead write time ty util

0% 0 0 0 0 0 0 0 0 0 0

8 24 0% - 2%

0% 0 0 0 0 0 0 0 0 0 0

16 8 0% - 1%

0% 0 1 0 1 0 0 1 0 0 0

0 0 0% - 0%
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Fcp Partner Path Misconfigured