PDA

View Full Version : RA4100 Redundancy


WS
September 8th 04, 12:31 AM
We have an RA4100 with dual RA4000 controllers that, a long time ago, was
set up for redundancy. What I want to do is remove this redundancy, so that
the second RA4000 controller in the unit operates as a separate path to the
same logical drives.

What piece of software/hardware controls whether this second controller is
in "redundant mode" or "additional path" mode?

Thanks in advance.

NuTCrAcKeR
September 8th 04, 03:18 AM
"WS" > wrote in message
...
> We have an RA4100 with dual RA4000 controllers that, a long time ago, was
> set up for redundancy. What I want to do is remove this redundancy, so
that
> the second RA4000 controller in the unit operates as a separate path to
the
> same logical drives.
>
> What piece of software/hardware controls whether this second controller is
> in "redundant mode" or "additional path" mode?
>
> Thanks in advance.
>

That isnt how redundancy works. Well, that isnt strickly true. You can have
2 HBA's in a system, and have one setup as a failover. You can have 2 RA
controllers in a chassis, and one has to be in standby mode. Through
combining multiple HBA's, multiple FCAL Hubs/Switches, and multiple RA
cabinets with redundant controllers, you can have a reasonably HA system.
But there will always be a momentary pause when the failover happens,
regardless of how much hardware you throw at the problem.

let me guess ... you are trying to build a cluster?

make sure that the firmware on the RA controller is 2.60. this includes the
ability to enable SSP (selective storage presentation) at the controller
level, and will allow more than 1 HBA access to a volume. However, only 1
HBA can access that volume at a time. This is due to the way that NT based
systems work with drive volumes and volume signatures. There is only 1 OS
platform that can have multiple systems accessing the same physical
filesystem at the same time. Only 1. And its a VAX. For 20 years, its what
every other platform has tried to be.

As for your question about dual path and all that ... what OS and version
are you running? NT4 ? 2000? 2003 ? Linux?

If I am wrong, tell me what you are trying to do and i will see what I can
do to help.

Ciao,

- LC

WS
September 8th 04, 10:05 PM
Hi There,

Thanks for your reply.

What I'm actually trying to do is to remove the redundancy. Previously, I
set it up so that each RA4000 controller in the 4100 chassis was attached to
its own Sanswitch 8-EL, and each server had two HBA's with one attached to
the first switch, and the other attached to the second switch.

Now that we have moved away from the cluster scenario, and given that we are
stuck with the 8-EL Sanswitches, I'd like to expand the number of servers
that we can connect to our RA4100 by allowing the servers HBA connection to
primarily connect to *either* the first RA4000 controller, or the second.

Question is: Is this even possible? Am I just going to ahve to bite the
bullet and purchase a larger switch? :o(

BTW: All our servers are running W2K3.


"NuTCrAcKeR" > wrote in message
...
>
> "WS" > wrote in message
> ...
> > We have an RA4100 with dual RA4000 controllers that, a long time ago,
was
> > set up for redundancy. What I want to do is remove this redundancy, so
> that
> > the second RA4000 controller in the unit operates as a separate path to
> the
> > same logical drives.
> >
> > What piece of software/hardware controls whether this second controller
is
> > in "redundant mode" or "additional path" mode?
> >
> > Thanks in advance.
> >
>
> That isnt how redundancy works. Well, that isnt strickly true. You can
have
> 2 HBA's in a system, and have one setup as a failover. You can have 2 RA
> controllers in a chassis, and one has to be in standby mode. Through
> combining multiple HBA's, multiple FCAL Hubs/Switches, and multiple RA
> cabinets with redundant controllers, you can have a reasonably HA system.
> But there will always be a momentary pause when the failover happens,
> regardless of how much hardware you throw at the problem.
>
> let me guess ... you are trying to build a cluster?
>
> make sure that the firmware on the RA controller is 2.60. this includes
the
> ability to enable SSP (selective storage presentation) at the controller
> level, and will allow more than 1 HBA access to a volume. However, only 1
> HBA can access that volume at a time. This is due to the way that NT based
> systems work with drive volumes and volume signatures. There is only 1 OS
> platform that can have multiple systems accessing the same physical
> filesystem at the same time. Only 1. And its a VAX. For 20 years, its what
> every other platform has tried to be.
>
> As for your question about dual path and all that ... what OS and version
> are you running? NT4 ? 2000? 2003 ? Linux?
>
> If I am wrong, tell me what you are trying to do and i will see what I can
> do to help.
>
> Ciao,
>
> - LC
>
>
>

szentthomas
December 11th 04, 02:30 AM
Can I ask you what HBA's you are using to get access to the RA4100's? and
what firmware level you are running? I am running into several issues
regarding HBA HW and RA4100.

Thanks

NuTCrAcKeR
December 11th 04, 08:37 AM
I have never been able to get those emulex cards (with the emulex driver and
HBAnywhere) to work with the RA4x00's. I have very limited success with the
default windows 2000 driver and these cards. Be sure that you configure the
bios so that the cards are running in a loop topology, and not a point to
point (unless you are using a fabric switch, and not an FCAL repeater).

I have scrounged a dozen or so StorageWorks Fibre Channel / P adpaters from
ebay. They work great. Not as fast as I thought they would be, though.

When I say limited success witht he emulex cards, I was never able to use
the ACU to configure the FC Controller in the RA. In order to do that, you
must use the StorageWorks controller.

I hope that helps ...

- LC

"szentthomas" > wrote in message
lkaboutcomputing.com...
> Can I ask you what HBA's you are using to get access to the RA4100's? and
> what firmware level you are running? I am running into several issues
> regarding HBA HW and RA4100.
>
> Thanks
>