6-1 © 2013 VMware Inc. All rights reserved VMware vSphere: Troubleshooting Workshop – Revision A...

6-1

© 2013 VMware Inc. All rights reserved

VMware vSphere: Troubleshooting Workshop – Revision A

Lesson 2:Troubleshooting

Fibre Channel Storage

6-2



After this module, you should be able to do the following:

Troubleshoot Fibre Channel Storage

This lesson was added by instructor. Slides can be downloaded at www.renright.com/work/fc.pptx

Learner Objectives

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Components in a Fibre Channel Storage Area Network

SPA

SPB

ESXi

ESXi

VM

K

VM

K

FCHBA’s

kernelqueue

FCSwitches

Storage Processers

FEPorts

AB

CD

SPA

AB

CD

0

1

3SPB

Disk Array Enclosure

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Storage Processors

Storage Processors. SP’s consist of three major components – Ports, cache and processors SP are always pair for redundancy.

Sometimes they are designated SP A & SP B

SPB

A

B

C

D

SPB

0

1

2

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Logical front end

A

B

C

D

A

B

C

D

FE Fibre

ChannelPorts

Front End Ports are used for host connectivity

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Cache

Directory Table(TOC)Cache is always

configured in pairs.

Parity or Mirrored

Protected

What Should

goes throughcache?

Everything.

Reads

WritesCommands

Cache slots

Memory is either

configurable or global

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SPA

SPB

0

1

2

Logical Back End

0

1

2

Back End Ports to connect to physical disks

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Physical Disks

A

B

C

D

SPA

A

B

C

D

SPB

Disk Array Enclosure

Most arrays use fiber cable through hubs to connect to the disks.

Disks are dual ported fibre channel or SSD disks

Link Control Cards

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Cache Function

Directory Table(TOC)

A

B

C

D

SPA

A

B

C

D

SPB

Read Hits, Read Misses, Fast Writes, Delayed Fast Writes

Read hit

ACK

Fast Write

0

1

2

3

0

1

2

3

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Module 2: VMware ESX/ESXi Server and Symmetrix VMAX Connectivity - 10

SPC-2 Bit Compliance Devices

Required for the proper functioning of:

VMware vSphere

VMware Site Recovery Manager

With SPC-2 enabled, devices are identified by their proper Network Authority Address (NAA)

vSphere will identify the devices as naa.DeviceWWN

• e.g. naa.60000970000194900632533030303444

The NAA identifier is unique for all paths where the ESXi host sees the device

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Fibre Channel SAN Components

VMware vSphere 4.1: Install, Configure, Manage – Revision A

FC FE Ports

StorageAdmin

SANAdmin

vSphereAdmin

FC Switch Ports

FC HBA Ports

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The FC HBA storage array is not supported.

Check VMware Compatibility Guide.

Verify that the LUN is presented correctly to the ESXi host.

The LUN is LUN Masked all the ESXi hosts.

The LUN Zoned to the ESXi hosts.

The LUN is not set to read-only on the array.

HOST ID on the array for the ESXi LUN is between 0 - 255.

The storage device is malfunctioning.

Use hardware diagnostic tools to identify the faulty component.

Mixing multivendor HBA’s

Never mix Qlogic with Emulex or Brocade

Possible Cause: Hardware-Level Issues

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Located in /proc/scsi/lpfc/# or /proc/scsi/qlaxxxx/#

For example: /proc/scsi/qla320/4 & /proc/scsi/qla320/5

The last number is a file without an extension. Reading the file will give you:

• Vender

• Model

• speed

• WWNN & WWPN

• FE Ports connected

• etc

Locating Fibre Channel HBA Properties

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Viewing FC HBA Information

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Viewing FC Storage

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90% of FC storage problems

Check to see that the Limit for maximum LUNs not reduced

• In advanced options, check to see that disk.MaxLUN is set to 256

Check to see that sparse LUNs not initiated

• In advance options, check to ensure that disk.SupportSparseLUN is set to 1

Back End Thin Provisioned storage not oversubscribed

• Ensure that VAAI is utilized

Possible Causes - Misconfiguration

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19

VMFS Volume Resignaturing – Mechanics (1)

AAAA

MyDatastore

(Signature)

naa.123456

With SPC-2, array serial number plus LUN ID are used to create naa ID. naa ID is used to create a disk signature.The disk signature is stored in hidden files, called metadata, at the base of each VMFS datastore.

Metadata

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22

VMFS Volume Resignaturing – Mechanics (4)

Replicating a LUN replicates original disk signature. ESXi will detect it is a replica because the replica’s disk signature does not match naa number.

BBBB(Computed signature)

Computed signature and volume

signature not the same. Volume must

be a replica.

AAAA

MyDatastore

(Signature)

naa.123456

AAAA

MyDatastore

(Replica)

(Signature)

naa.654321

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23

ESXi 5.X – VMFS Volume Resignaturing

By default, an ESXi host will not display a datastore with a mismatched disk signature. If host can see orginal datastore, it will see two datastores with the same signature. Can then read from or write to either. Can cause inconsistent data.

VMware vSphere has the ability to individually resignature and/or mount VMFS volume copies

Use vSphere Client

Or the CLI utility “vicfg-volume” for ESXi

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Module 5: Data Replication - 24

ESX 5.x – VMFS Volume Resignature – vSphere Client

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25

ESXi 5.0 – VMFS Volume Resignature – CLI

Cannot be mounted as original is still online – Can be resignatured

-m – non persistent mount can only be done via CLI

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Fixed (Default for most Active/Active arrays) Works with a preferred path and an active path

Most Recently Used (Default for Active/Passive Arrays) Works with an active path on the active storage processor

Round Robin (default for some Active/Active Arrays in vSphere 5.1)

Assigning Fixed to an Active/Passive array can result in LUN thrashing with prevents access to the LUN.

NMP Path Selection Policies

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To List SATP’s & PSP’s

esxcli storage nmp satp listesxcli storage nmp psp list

Change new paths on A/A arrays to Round Robin:

esxcli storage nmp set –s VMW_SATP_DEFAULT_AA –P VMW_PSP_RR

By default Round Robin changes paths every 1000 I/O’s. To change the I/O or to set it to bytes use

esxcli storage nmp psp roundrobin deviceconfig set --type –B XXXX –d naa.xxxxxxxxxxxxxxx

Or

--type –I 1 –d naa.xxxxxxxxxxxxxxxxxx

ESXCLI Commands for changing Path Selection Policies

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Multipathing with Fibre Channel

Multipathing allows continued access to SAN LUNs in the event of hardware failure. It also provides load balancing.

VMware vSphere: Install, Configure, Manage – Revision A

(optional)

FC FE PortsSPBSPA

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