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Migration to NPIV Can Improve Security and Performance


Editor’s note: This is the first of two articles on converting logical unit numbers (LUNs) from virtual SCSI to N-Port ID Virtualization (NPIV).

The devil is in the details when deciding to convert vSCSI-mapped to NPIV-mapped LUNs. It takes research, planning, checking and double-checking before making the transition. This, however, shouldn’t dissuade you. Ultimately, a LUN is a LUN—whether it’s presented to a Virtual I/O (VIO) server or a client partition.

So why make this change in the first place? NPIV provides several benefits, including:

  • Simplified adding and identification of LUNs. In NPIV, the actual partition is assigned the LUN, so there’s no need to map in the VIO server.
  • Improved performance. With NPIV, all paths to the LUNs can be balanced, allowing the VIO servers to share the I/O load.
  • Security. Because the client partition is the only server to see the disk, there’s less risk of someone accidentally accessing a LUN containing sensitive information— or worse, reformatting it because they didn’t know it was in use.

Migration Process

Those are some of the reasons to migrate. Now, let’s walk through the process. Note that while this overview is meant to provide a guide, additional commands and steps might be needed depending on your specific environment. The three major steps in the migration process are:

  1. Identification
  2. Setup and mapping
  3. Execution and cleanup

1. Identification

First, you’ll need to verify your environment is set up to handle NPIV LUNs. Your system must meet minimum levels of software, in terms of both the Hardware Management Console and OS. Likewise, several Fibre Channel (FC) cards support NPIV, and the first set of switches you connect to need to be NPIV-capable. The newer the hardware is, the more likely it will support NPIV. The lsnports command will list all of a VIO server’s NPIV-capable ports.

Next, work with your storage-area network (SAN) administrator to determine which volumes you’ll be converting. If it’s multiple volume groups, it’s wise to tackle one group at a time. This will save you the trouble of mapping the new hdisks to the correct volume group during the migration. The SAN administrator should provide the name and a unique identifier for each LUN mapped to your VIO server.

Then, gather information from your client partitions and VIO servers. On the client partition, use lspv to list the physical disks and their associated physical volume identifiers (PVIDs). Next, run the same command on the VIO servers. You must match the PVIDs of the volume group being migrated to the hdisks on the VIO servers. Now find the unique_id for each of these disks, using this command:

lsattr –El hdiskx | grep unique_id

To Be Continued

With this information, you can map the unique ID from the VIO servers to the unique identifier from your SAN administrator. Create a spreadsheet, like Table 1, to keep the information straight. The NPIV WorldWide Port Names (WWPNs) will be added once the client FC adapter is created in the next step, which will be covered in Part 2 of this series. That article will also describe how to take this information to prepare your environment and execute the migration.

VIO
LUN
VIO
WWPN
PVID VIO
Unique_ID/
V7000 UID
V7000 LUN Name Client NPIV WWPN LPM NPIV WWPN
hdisk5 100000
00c9ab
c894
00f693
4c79fc
a682
600507
680282
81499C
000000
000000
41
b740test_vscsi1    

Andrew Goade is an architect for Forsythe Technology Inc. He can be reached at agoade@forsythe.com.



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