ESX hosts to lose storage when CLARiiON failover mode changes during storage processor reboot (1038308)
- ESX hosts to lose storage when CLARiiON failover mode changes during storage processor reboot
- During scheduled reboot of a storage processor, one or more servers initiator's failover mode changes from
Active/Active Mode (ALUA) - failovermode 4to
Active/Passive Mode (PNR) - failover mode 1
This failover mode change can cause the ESX servers to lose storage completely during a second Storage Processor (SP) reboot.
In ESX 4.x, the ESX host agent tries to register the host with failover mode 1 - it does this because the SP rebooted and lost connection with the array. When the array comes back up, the ESX host re-registers and must use a hard coded failover mode of 1.
- In the EMC Unisphere, disable the ArrayCommPath parameter for each ESX host.
Note: Disabling ArrayCommPath for each host requires a reboot of each host.
- Present a 2GB or larger LUN0 to all ESX hosts.
Note: This volume does not need to be formatted, but must be equal to or larger than 1.5GB.
- Rescan each ESX Server to see if they are now seeing LUN0 rather then LUNZ. If not, then run a rolling reboot of all ESX hosts.
A LUNZ is the pseudo LUN that is presented to all hosts prior to any real LUNs being assigned to the host (in the Storage Group). The very first LUN assigned to a host in the Storage Group is assigned the Host LUN Number (HLU) of zero (0) by default. If you manually assign the HLU and do not use zero (0), the host sees the LUNZ.
LUNZ always presents as a PNR (A/P) device (barring an actual LUN 0 being presented). In Flare versions 4.30 and below, when ESX attempts to push a registration in PNR mode to the array, the array refuses to update the registration that already existed. Remaining volumes come up in ALUA mode and are fully functional.
esxcfg-scsidevs -l -d <naaID>
Device Type: Direct-Access
Size: 0 MB
Display Name: DGC Fibre Channel Disk (naa.50060160bb201bc550060160bb201bc5)
Multipath Plugin: NMP
Console Device: /dev/sdi
Devfs Path: /vmfs/devices/disks/naa.50060160bb201bc550060160bb201bc5
Vendor: DGC Model: LUNZ Revis: 0430
SCSI Level: 4 Is Pseudo: true Status: on
Is RDM Capable: true Is Removable: false
Is Local: false