Lesson 2: Troubleshooting Fibre Channel Storage

Lesson 2:TroubleshootingFibre Channel Storage

Learner Objectives 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

Components in a Fibre Channel Storage Area Network Storage Processers FCSwitches 0 1 3 SPA SPA ESXi FCHBA’s D Disk Array Enclosure C VM K kernelqueue B A ESXi VM K SPB SPB D C B A FEPorts

Storage Processors 0 1 2 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 SPB D C B A

Logical front end Front End Ports are used for host connectivity FE FibreChannelPorts D C B A D C B A

Cache Directory Table(TOC) What Should goes throughcache? Everything. Reads WritesCommands Cache is alwaysconfigured in pairs.Parity or Mirrored Protected Cache slots Memory is either configurable or global

Logical Back End SPA 0 1 2 0 1 2 Back End Ports to connect to physical disks SPB

Physical Disks SPA D Disk Array Enclosure Most arrays use fiber cable through hubs to connect to the disks. Disks are dual ported fibrechannel or SSD disks C B A SPB D C Link Control Cards B A

Cache Function SPA 0 1 2 3 Directory Table(TOC) Read hit D C B A Fast Write ACK SPB 0 1 2 3 D C B A Read Hits, Read Misses, Fast Writes, Delayed Fast Writes

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

VMware vSphere 4.1: Install, Configure, Manage – Revision A Fibre Channel SAN Components StorageAdmin FC FE Ports SANAdmin FC Switch Ports FC HBA Ports vSphereAdmin

Possible Cause: Hardware-Level Issues 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

Locating Fibre Channel HBA Properties 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

Viewing FC HBA Information

Viewing FC Storage

Possible Causes - Misconfiguration 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

VMFS Volume Resignaturing – Mechanics (1) With SPC-2, array serial number plus LUN ID are used to create naaID. 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 AAAA (Signature) naa.123456 MyDatastore

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) AAAA AAAA (Signature) (Signature) Computed signature and volume signature not the same. Volume must be a replica. naa.123456 naa.654321 MyDatastore MyDatastore (Replica)

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

Module 5: Data Replication ESX 5.x – VMFS Volume Resignature – vSphere Client

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

NMP Path Selection Policies 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.

ESXCLI Commands for changing Path Selection Policies To List SATP’s & PSP’s esxcli storage nmpsatp listesxcli storage nmppsp 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 nmppsproundrobindeviceconfig set --type –B XXXX –d naa.xxxxxxxxxxxxxxx Or --type –I 1 –d naa.xxxxxxxxxxxxxxxxxx

VMware vSphere: Install, Configure, Manage – Revision A Multipathing with Fibre Channel Multipathing allows continued access to SAN LUNs in the event of hardware failure. It also provides load balancing. FC FE Ports (optional) SPB SPA

Lesson 2: Troubleshooting Fibre Channel Storage