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Unpluging half of mirror before major changes

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Juha Rimmi

Unpluging half of mirror before major changes


I have several ML310 and 350 servers where I usually has HotSwap Disks mirrored. Before any major changes to the system it would be wonderful to disconnect the other half of the mirror. After the changes are done decide based on the results which disks (original or altered) has "better" configuration and use them. Suppose that the mirror needs to be build again.

I'm not skilled enough to try this before some guidance. Do you know a link to the article which can help me with this?

Thanks in advantage,

Honored Contributor

Re: Unpluging half of mirror before major changes

I think it's not documented by HP =)

But if You have RAID1 mirror with two disks. Unplug other carefully if doing it online(make sure no disk I/O is ongoing or shut down the server).

continue with updates, if everything is like you wanted, plug the disk back and it will automatically sync the data.

OR if You want to go back to original state.
Power off server, and put the original disk back in and plug out the "altered" disk.

Do not change the disk slots in any phase
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Acclaimed Contributor

Re: Unpluging half of mirror before major changes

Power off the server, pull the disk and power on. Confirm the message about a degraded RAID if needed.

Do your modifications.

If all went well, just push back the disk.

If get into trouble, power off the server, push the backup disk and pull the "failed" disk.

Boot up and insert the "failed" disk again.

Hope this helps!

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those who understand binary, and those who don't.

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Honored Contributor

Re: Unpluging half of mirror before major changes

First verify which controller you have, SAS or builtin SATA (B110i)

Here is a document for mirror splitting and recombining

And a more general one for the SA RAID controllers

And finally one about this forum

Juha Rimmi

Re: Unpluging half of mirror before major changes

Thak you very much!

This is what I was lookin for. Actually, c00378986.pdf explains how to increase disk size easily using these "tricks". (Thanks TTr).

Furthermore. I'm considering use BitLocker with 2008 std (e200i controller). Wonder if that will somehow prevent using these tricks?

Thanks again,

Honored Contributor

Re: Unpluging half of mirror before major changes

The OS only sees the logical disk that the raid controller presents to it and the bitlocker operates at the OS level so it will not be affected by these backend operations. The only time you may have to be careful is when and if you increase the logical disk size in the raid card and at the same time increase the volume size at the OS level.