Re: [PLUG] SAN Questions

["Sean Cummins" <sean.cummins@gmail.com>]

Disclaimer first -- I work for EMC.  I know you're looking primarily
for user opinions, but I figured I'd give you some quick feedback as
well.

- You'll find supported HBA's available from Emulex or Qlogic.
- HBA drivers are generally not included in the Linux distributions --
you will have to load them post-install.  Or if you're using VMware
ESX server, the drivers are included in the VMware distro.
- You'll need the HBA drivers themselves, HBA firmware, management
utilities (eg. SANSurfer or HBAnyware), array management host software
(eg., Solutions Enabler, Navisphere), and multipath software (eg.,
Powerpath).
- The HBA drivers are supported by the HBA manufacturers and EMC.
- Powerpath has essentially the same look, feel, and functionality on
Linux as Solaris/HPUX/AIX.  VMware ESX has its own multipathing built
in.
- I'm not aware of any hot-swappable HBA support on Linux.

- Once the HBA's are logged into the fabric, you can see the WWN's
from your switch management tools.  eg., ECC, Connectrix Manager,
Brocade Web Tools, Brocade switchshow, Cisco Fabric Manager, Cisco
"show fcns database", etc.  Or you can use the HBA management tools
you loaded on the Linux servers to discover the HBA's from the host
side (eg., HBAnywhere, SANSurfer).

- There are several ways to discover new SAN devices from Linux.. the
easiest would be to either reboot, run the rescan utility included
with the Emulex driver, or reload the HBA driver.

- Once the new devices are visible to the host, you can use
essentially the same procedures for creating filesystems as you would
with a local disk.  eg., use fdisk to create a partition, then mkfs to
create a filesystem on the partition.  You'll want to create your
partition on the Powerpath pseudo device (assuming you're using
Powerpath), and you'll want to align the partition to the underlying
LUN during creation, for optimal performance.


Hope that helps,

- Sean




On 5/29/07, Mag Gam <magawake@gmail.com> wrote:
> Hi All,
>
>     Linux is an operating system that has evolved greatly in the academic,
> personal, and perhaps the most in the enterprise sector. My co-workers and I
> work on AIX on a daily basis, and we have been pondering some day-to-day
> tasks, and wondering how Linux handles them. These tasks include anywhere
> from HBA connectivity between host & switch, LUN/Physical volume management,
> and last the overall benefit of using Linux in the enterprise.
>    HBA connectivity between host & switch is critical to provide high
> performance storage to the application.  We were wondering, what type of
> HBAs are available? Are the HBA modules already part of the Linux core
> kernel? What other modules are required to have HBA+SCSI children devices?
> Are these modules supported by vendors (ie Redhat, SuSE)? How does
> multi-path software compare to other Unix flavors (EMC PowerPath)? Also, is
> there such a thing as a hot swappable HBA for Linux hardware?
>   Second, couple of questions pertaining the LUN and physical volume
> configuration: once the HBA is logged into the fabric, how does one see its
> WWN?  How do you scan the I/O board for new LUNs (Physical Disks)? Is a
> reboot required to introduce new LUNs? Once a LUN is zoned to the HBA's WWN,
> what is the exact procedure to create a filesystem on it?
>   Last perhaps the most important, what is the overall experience with Linux
> in the enterprise level? Being a  Linux group, I guess I should expect some
> biased answers. We are currently evaluating Linux , and wondering if its
> ready for some of our "Tier 3" applications, and wanted some feedback from
> people who work on it from a day-to-day basis, instead of a Vendor.
>
>  Thanks in advance for your replies!
>
>
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