Specifications

VMware, Inc. 269
Chapter 9 Storage and File Systems
In!this!example,!vmhba0!and!vmhba2!only!scan!LUNs!0‐7,!but!vmhba1!and!vmhba3!scan!
all!LUNs!that!are!not!masked,!up!to!LUN!255,!or!the!maximum!LUN!setting!reported!
by!the!adapter,!whichever!is!less.
For!administrative!or!security!purposes,!use!LUN!masking!to!prevent!the!server!from!
seeing!LUNs!that!it!doesn’t!need!to!access.!Refer!to!your!documentation!on!disk!arrays!
for!more!information.
Using IBM FAStT Disk Arrays
An!IBM!FAStT!disk!array!sometimes!returns!vendor‐specific!status!codes!that!ESX!
Server!interprets!as!errors.!These!status!codes!are!temporary!indicating,! for!example,!
that!the!firmware!has!been!upgraded!or!that!the!battery!for!the!disk!cache!needs!to!be!
charged.!ESX!Server ,!in!its!default!configuration,!might!interpret
!these!status!codes!to!
mean!that!a!LUN!exists!but!is!not!accessible.!
Avoid!this!problem!by!using!a!special!ESX!Server!configuration!option.!Log!in!to!the!
management!interface!as!the!root!user,!click!Advanced!Settings,!and!click!VMkernel!
Configuration.!Find!the!option!DiskRetryUnitAttention!and!make!sure!it!
is!enabled!
(the!default).
With!this!option!enabled,!ESX!Server!retries!SCSI!commands!when!these!
vendor‐specific!status!codes!are!received.
Using!IBM!FAStT!disk!arrays!with!ESX!Server!requires!additional!configuration!
options!that!are!described!in!more!detail!in!the!VMware!Knowledge!Base!at!
http://kb.vmware.com/vmtnkb/supportcentral/supportcentral.do?id=m1.
Troubleshooting SAN Issues with ESX Server
You!can!view!LUNs!through!the!VMware!Management!Interface!or!view!the!output!of
ls /proc/vmware/scsi/<FC_SCSI_adapter>.!If!the!output!differs!from!what!you!
expect,!check!the!following:
! DiskMaxLUN!–!Maximum!number!of!LUNs!per!vmhba!that!are!scanned!by!ESX!
Server.
View!and!set!this!option!through!the!VMware!Management!Interface!(Advanced!
Settings!in!the!Options!page)!or!through!/proc/vmware/config/Disk.
! DiskSupportSparseLUN!–!If!this!option!is!on,!ESX!Server!scans!past!any!missing!
LUNs.!If!this!option!is!off,!ESX!Server!stops!scanning!for!LUNs!if!any!LUN!is!
missing.
View!and!set!this!option!through!the!VMware!Management!Interface!(Advanced!
Settings!in!the!Options!page)!or!through!/proc/vmware/config/Disk.