Re: how much disk was I using?

[Jim Oberholtzer <midrangel@xxxxxxxxxxxxxxxxx>]

RAID-5  Very good
RAID-5 with hot spare better
RAID-6 slightly better than RAID-5 with hot spare
RAID-6 with hot spare =  the potential to loose the system is so small 
as to not matter, and almost a statistical dead heat with mirroring 
(although not quite as good but far, far and away less expensive)

All this assumes the big dog RAID adapters and a normal  I/O footprint 
that's not really heavy.

Jim Oberholtzer
Chief Technical Architect
Agile Technology Architects


On 3/22/2013 2:03 PM, rob@xxxxxxxxx wrote:
> My boss asked me how much disk we were using on one rack.  Keep in mind
> that this rack supports five lpars, only one of them is guested.  My
> initial thought was to do a summary of WRKSYSSTS (and whatever I had to
> for that one Linux lpar), and ignore the guested lpar.  After I summarized
> that I thought, maybe I better count the number of each type of disk and
> multiply it by the size of that disk type.  You know, like 70GB times #
> 70GB drives, 140GB times # 140 drives, 280GB times # 280GB drives...
>
> We have a few disks.
>
> Turned out there was a TB difference between WRKSYSSTS and the latter
> calculation.  Oh well, turns out there's a bit of loss due to RAID.  Sure
> we all knew that but I'm glad I remember that before the boss spec'd up a
> new system based on the earlier numbers.  I also told him that on my minor
> wish list was hot spares...
>
>
> Rob Berendt
> -- IBM Certified System Administrator - IBM i 6.1 Group Dekko Dept 
> 1600 Mail to: 2505 Dekko Drive Garrett, IN 46738 Ship to: Dock 108 
> 6928N 400E Kendallville, IN 46755 http://www.dekko.com
> --