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Linux ServiceGuard with 2 unit MSA1000 .

kevin leong
Frequent Advisor

Linux ServiceGuard with 2 unit MSA1000 .

Dear ALl ,
Any one have be done configure with 2 unit MSA1000 + mirror data on linux service guard?
6 REPLIES
kevin leong
Frequent Advisor

Re: Linux ServiceGuard with 2 unit MSA1000 .

Hi steven ,
Maybe i provide with the diagram is better .

My problem is can't mirror second storage smoothly intergrated in linux service guard.

Thanks
LeongKO
Uwe Zessin
Honored Contributor

Re: Linux ServiceGuard with 2 unit MSA1000 .

That does not look like a valid configuration unless you have done some creative zoning on the fibre channel switches.

Move the second link of server A from switch A to switch B. Move the first link of server B from switch B to switch A. Cut the link between switch A and switch B.

Make sure the connection profiles on the MSA1000s are all set correctly. The normal value for 'Linux' is, well, 'Linux', but SG might need a different value.
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kevin leong
Frequent Advisor

Re: Linux ServiceGuard with 2 unit MSA1000 .

Dear ,
I can't cut the link in between both switch ,because this is different building .

Thanks
LeongKO
Uwe Zessin
Honored Contributor

Re: Linux ServiceGuard with 2 unit MSA1000 .

Then you need one additional fiber link between the buildings so that you cut the link and properly attach the servers to both switches or you need to set up zoning on the fabric. It is important that a single Fibre Channel adapter in a server has only access to one controller in an MSA1000.
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Serviceguard for Linux
Honored Contributor

Re: Linux ServiceGuard with 2 unit MSA1000 .

I believe you are asking for the equivalent of the extended distance cluster we support on HP-UX. An example would be having on server and an MSA1000 in one location, a second server and a second MSA1000 in another location, and all of the right cabling to be able to use software mirroring to make sure the data is copied to both MSA1000.

All that said, we don't yet support that configuration. The reason being that MD is the only software mirroring shipped by RedHat and SUSE (that I'm aware of right now) and it is not "cluster aware". What that means is that there are a few corner case failure scenarios that could lead to data corruption. The other issue with MD is that when a server fails, and the MD RAID1 array is restarted, it remirrors the entire array more than 50% of the time (at least that is the experience I have in the testing we've done).

We will be looking and waiting for software RAID functionality that can easily be used in this configuration.

Another thing to be aware of, LockLUN is not designed to handle this configuration. You would need the Quorum Service and it should be placed where it can survive whatever disaster you are planning for.