Re: Raid Configuration

[DrFranken <midrange@xxxxxxxxxxxx>]

Steve pretty much nailed it. One additional point:

YOU (meaning your company) need to decide if the risk of data loss dur 
to being unprotected during a RAID5 rebuild is high enough to take the 
performance penalty of RAID6.  Obviously IF you lose a second drive 
during a RAID 5 rebuild it's 'where's the tape?' time. Not likely of 
course statistically but then someone does win the lotto now and then....

        - Larry "DrFranken" Bolhuis

www.Frankeni.com
www.iDevCloud.com - Personal Development IBM i timeshare service.
www.iInTheCloud.com - Commercial IBM i Cloud Hosting.

On 12/4/2015 7:46 AM, Steve Pavlichek wrote:

> RAID6 is a little slower due to 2 parity drives but better protection.
> I usually recommend RAID5 with hot spare
>
> You also have choices of Performance or Capacity option when starting
> RAID. Performance option will give you 2 RAID sets and Capacity will
> give you 1 set.
>
> Here's a link to Sue Bakers parity set Techdoc
> https://www-03.ibm.com/support/techdocs/atsmastr.nsf/WebIndex/TD105880
>
>
> -----Original Message----- From: Gad Miron
> Sent: Friday, December 04, 2015 3:41 AM
> To: midrange-l@xxxxxxxxxxxx
> Subject: Raid Configuration
>
> To the Hardware guys
>
> a quick one:
>
> Due to replacing 3 SSDs installed for test puposes with (the original) 3
> HDDs
> The BP is breaking the existing RAID5 set of 15 HDDs and is going to build
> a 18 HDDs
> RAID5 set (adding 3 HDDs)
>
> My question, should we build istead a RAID6 set ?
> what are the pros & cons?
>
> This is a 8286 41A P8 machine with 18  283GB 15K discs all in the CEC
> (plus 8 more in expansion 5887)
> I believe that there is a  EJ0P on-board controller .
>
> So RAID5 or RAID6 ?
>
> thanks
> gad