MCS 7845 H2 RAID Configuration

Answered Question
Sep 2nd, 2010
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Hi,


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


Thanks,

Nelson

Correct Answer by Aaron Harrison about 6 years 6 months ago

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

Correct Answer by Aaron Harrison about 6 years 6 months ago

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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nelson.chu Fri, 09/03/2010 - 07:56
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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.

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Aaron Harrison Fri, 09/03/2010 - 08:01
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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 Fri, 09/03/2010 - 08:04
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Thanks, Aaron - that reminded me. The CUCM install disk will configure the RAID array for you.

David Hailey Fri, 09/03/2010 - 08:02
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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 Fri, 09/03/2010 - 08:09
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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

Correct Answer
Aaron Harrison Fri, 09/03/2010 - 08:21
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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 Fri, 09/03/2010 - 08:30
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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

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