Storage Area Networks For Dummies®

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Par t I: SAN 101
If you’re purchasing all your SAN components from a single vendor, the vendor
should be able to recommend what’s best. Most SAN vendors have very expensive
integration labs, where they test all the different combinations of servers,
storage, switches, and host bus adapters. After this exhaustive testing is done,
they create a certification matrix, which is a listing of all the device combinations
they have certified to work with their storage. Many vendors make you
choose components from this certified list of products. We recommend using
the host bus adapters that are listed in the matrix for that vendor.
The two dominant HBA vendors are
✓ Emulex: www.emulex.com
✓ QLogic: www.qlogic.com
Brocade (a major SAN switch vendor at www.brocade.com) has also entered
the HBA market.
For iSCSI and Infiniband protocols, you can use Intel or Mellanox, in that
order. (An Infiniband adapter is called an HCA, or Host Channel Adapter; an
iSCSI network card is called a TOE adapter, or TCP/IP Offload Engine adapter.)
Each HBA vendor has strengths and weaknesses. Some of their products work
better than others on a particular operating system and server platform. Your
SAN vendor can advise you about which HBA to use with your particular
operating system(s) and storage array. The HBA driver is the most important
aspect of an HBA when it comes to the operating system. I have had great
experiences with Emulex on the Windows platform, and Qlogic works great
with the Unix and Linux platforms. Some of the storage vendors even repackage
these HBAs as their own. For example, when you order an HBA using IBM
part numbers for a host bus adapter, you get a re-branded Emulex HBA. When
it comes to host bus adapters, standardization is a good thing; try to use the
same HBA vendor across all your server platforms if possible.
Going with a single vendor
Standardize using a single vendor if possible. That way, if you have to
upgrade the driver that the HBA uses to talk to the operating-system software,
you can just get the latest version for your standard HBA from that vendor’s
Web site and upgrade all your servers to the newer version.
Using multiple HBA vendors means that you have to track any new driver versions
from every vendor you use.