Edit: I must have really liked this Redbook. Facts and features seem harder to find, you can search for smarter system for a smarter planet videos. I could not find a working link to the POWER7 article about not validating SPARC. None of the links at the end still seem to work.
Originally posted February 16, 2010 on AIXchange
The now published IBM Redbook, “PowerVM Migration from Physical to Virtual Storage,” contains a wealth of valuable information. Here are a few more highlights.
* Choosing a SAN disk — The authors of the Redbook detail the various methods for determining which SAN disk to use when virtualizing: Physical Volume Identifier (PVID), IEEE Volume Identifiers and Unique Device Identifiers (UDID).
* The new chkdev command — Lots of material here. As the authors state:
“As of Virtual I/O Server Fix Pack 22, a new command has been introduced to assist with the identification of disks and their capabilities. The Virtual I/O Server chkdev command is capable of displaying the same values as mentioned previously (IEEE, UDID, and PVID) but provides some additional information:
#chkdev
NAME: hdisk0
IDENTIFIER: 2F1135000C50006D9C1F30BST9146802SS08IBM-ESXSsas
PHYS2VIRT_CAPABLE: YES
VIRT2NPIV_CAPABLE: NA
VIRT2PHYS_CAPABLE: NA
* What can be virtualized? Again, I’ll let the authors tell you:
“PHYS2VIRT_CAPABLE: This disk may be virtualized to a logical partition. Once this is performed, this field will change to a value of NA if the mapping is successful. A value of NO indicates this volume may not be virtualized.
“VIRT2NPIV_CAPABLE: If the disk is capable of moving from a virtual SCSI environment to an N_Port ID Virtualization (NPIV) environment, this field will be set to YES, otherwise it will be set to NO. A value of NA means that this disk has already been moved and the Virtual Target Device or VTD as it is abbreviated in the command output, will indicate the mapping.
“VIRT2PHYS_CAPABLE: If the device is capable of moving from a virtual environment to a physical environment and is currently mapped to a VTD then the value here will be YES. A value of NA means the disk is not in use by a VTD, while a value of NO means the disk is not capable of such a move. For further information, please refer to the Virtual I/O Server chkdev manual page.”
* It figures — The Redbook also includes some nice charts (see the Figures section in the table of contents) that help make concepts clear. For example, Figure 2-1 shows the relationship between physical SCSI disk and the target SCSI device on the Virtual I/O Server. Figure 2-2 shows the relationship between physical SCSI disk and the virtual SCSI devices on a client partition.
* NPIV — As we reduce our reliance on physical adapters, and with more customers adopting NPIV, it’s nice to see this topic covered:
“N_Port ID virtualization (NPIV) is a technology that allows multiple logical partitions to access independent physical storage through the same physical Fibre Channel adapter. Each partition is identified by a pair of unique worldwide port names enabling you to connect each partition to independent physical storage on a SAN. Unlike virtual SCSI, only the client partitions see the disk. The
Virtual I/O Server acts only as a pass-through managing the data transfer through the POWER Hypervisor.”
Finally, there’s this interesting note on page 29:
“A POWER Hypervisor has a limit of 32,000 pairs of WWPNs. If you run out of WWPNs, you must obtain an activation code for an additional set of 32,000 pairs.
“Each time you configure a virtual Fibre Channel adapter, whether dynamically or by adding to a partition profile, the HMC obtains a new, non-reusable, pair of WWPNs from the POWER Hypervisor. Therefore, the correct procedure for dynamically allocating a virtual Fibre Channel adapter to an active partition that must keep the configuration across a partition shutdown is to first dynamically allocate the adapter to the partition and then to use the HMC Save Current Configuration feature to save the configuration to a new profile. This new profile then must be used to start the partition after a shutdown. This will ensure that the WWPNs that were allocated during the dynamic operation will be the same ones in the profile. If instead, you dynamically add an adapter and then add an adapter to the
partition profile, the partition will come up with a different pair of WWPNs after a partition shutdown and access to the storage will be lost.”
This summary — and this, and this — barely scratch the surface when it comes to summarizing the valuable information in this publication. So take the time to read this Redbook.
Also, some interesting response to the POWER7 announcement:
* “POWER7 has the most remarkable on-chip cache hardware of any processor on the market.”
* Smarter systems for a smarter planet
* POWER7 does not validate Sun’s CMT SPARC Processor Architecture
* Active Memory Expansion Performance