MCS 7845 H2 RAID Configuration

[nelson.chu]

Hi,

What is "Best Practise" for setting up RAID on a (4) Disk system on MCS 7845 H2 servers?

Thanks,

Nelson

[David Hailey]

RAID 1 - see the following:

http://www.cisco.com/en/US/prod/collateral/voicesw/ps6790/ps5748/ps378/product_data_sheet0900aecd80587390.html

Hailey

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[nelson.chu]

For RAID 1, it requires (2) Hard Drives for mirroring.  If there are (4) disks in the MCS 7845, what are the (2) other disks used for?  This is not clear to me.

[Aaron Harrison · Accepted solution]

Hi

Typically you would have 2 X RAID1 arrays.

Two logical drives presented to the OS, each one based on two physical disks in a mirrored config.

In general it's not something you need to worry about; most applications have a scripted platform build process that identifies the hardware and builds RAID configs appropriately.

Regards

Aaron

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[David Hailey]

Thanks, Aaron - that reminded me. The CUCM install disk will configure the RAID array for you.

[David Hailey]

RAID 1 requires a MINIMUM of 2 disks but is not exclusive to 2 disk configurations. RAID 1 can be implemented with 3 or more disks as well.

Maybe someone else can weigh in on this and provide further clarification as well.

Hailey

[nelson.chu]

Hi,

This is related to my other post about upgrading 4.2 to 7.1(2).  Is it possible to split the mirror drives?  This is part of fallback plan when upgrading the clusters.

Thanks,

Nelson

[Aaron Harrison · Accepted solution]

It is possible, yes; but only as a quick reversion option (i.e. make sure you have the original system backed up using BARS in case a problem occurs).

When you rebuild the server with a new CM version, the RAID array config will probably be wiped and rebuilt, and firmware versions will be changed etc, so you may have problems reverting even if you do this carefully (i.e. shut down the server before splitting, maintaining the correct positions of the disks, etc). You also need to have the server fully populated when doing the build of CM7 or it will see an incorrect disk count and either assume you have a lower spec server or refuse to build.

Regards

Aaron

[nelson.chu]

Hi,

We have a lab setup and it duplicates the production environment.  I want test this before doing it on the live system.  Someone on my team brought up this option during our planning session.

Thanks all,

Nelson