SSA uses the "pdiskX" notation to specify a physical disk drive in the
SSA loop. SSA RAID arrays are built using collections of pdisks and
present this collection to the AIX LVM as an hdisk.
If you do not configure your SSA disks in a RAID array, then 1 pdisk => 1
hdisk. Note that the value of X does NOT have to be (and in most cases is
not) the same between 'pdiskX' and 'hdiskX'
To find out what pdisk is associated with a given hdisk or vice versa, you
can use the 'ssaxlate' command.
AFAIK SSA is the only thing that uses the "pdisk" nomenclature.
> if you arange 5 SSA Disks in a, for example RAID-5, then you have 5
> pdisks and one hdisk.
> > Following AIX LVM terminology a VG is a collection of disks. A disk or
> > PV is represented by hdiskx. For example, hdisk0 is typically the disk
> > in rootvg. So what then is a pdisk or physical disk?
> > Carrying out the following commands only serves to confuse the issue:
> > # lscfg -vp pdisk0 | grep pdisk0
> > # pdisk0 00-05-P 4GB SSA C Physical Disk Drive
> > # lscfg -vp hdisk0 | grep hdisk0
> > # hdisk0 00-07-A1-3,0 2.2 GB 16 Bit SCSI Disk Drive
Scott A. Ellerman \ IBM Certified
Lab Administrator \ Advanced Technical Expert - AIX
GSM/UMTS Call Server OA&M Integration (2I38)\ Specialist - RS/6000 SP
Nortel Networks \ Specialist - AIX HACMP
Any opinions expressed in this message are mine alone and not those
of Decision Consultants Inc., IBM, or Nortel Networks, unless expressly