Re: RAID definition

For a system of that size, I have to wonder why RAID-10, that seems like
real overkill to me. RAID-6 with hot spare will be nearly as safe
statistically and in all honesty are you not going to notice that many
drives failing? You'll get a bit better I/O performance with RAID-10 but
I'll bet if you compare it to RAID-6 and fewer units to get the same
storage you might just get close enough in price to get the SSDs.

Me thinks you need a business partner that does not just take the defaults
in the configurator and actually thinks about what you need and the best
way to approach it.

Jim Oberholtzer
Chief Technical Architect
Agile Technology Architects

On Thu, Aug 9, 2018 at 9:38 AM, Jim Hawkins <jhawkins@xxxxxxxxxxxx> wrote:

Larry is correct on the RAID 10 configuration. We just found that to be a
confusing way to state it, as Rob first suggested, two separate RAID sets
seems to be the way to read it.

We went with the spinning drives over SSD because of cost. Our current
system uses about 300GB running at around 65% full, so we wanted a little
more room, there are some things we have not done because of disk space.
Yes
we keep our systems for a very long time. The only reason we are getting a
new system now, is because come March, it will longer be eligible for
maintenance. The cost of a single SSD was twice the cost of all 10
spinning
drives, and as was mentioned, we understand that when these come off the
initial contract, they can be expensive to have a continued maintenance
contract on. We get that SSDs are faster, we have had little complaint
about the speed of our current system and the new one will 3x the CPW of
the
current box.

Regards,

Jim Hawkins
Programmer Analyst
Interkal LLC
Kalamazoo, MI


date: Thu, 9 Aug 2018 09:55:02 -0400
from: Rob Berendt <rob@xxxxxxxxx>
subject: Re: RAID definition

Didn't they also just drop the terminology "read intensive" from
mainstream SSD's?


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





From: "Diego Kesselman" <diegokesselman@xxxxxxxxx>
To: "Midrange Systems Technical Discussion" <midrange-l@xxxxxxxxxxxx>
Date: 08/09/2018 09:51 AM
Subject: Re: RAID definition
Sent by: "MIDRANGE-L" <midrange-l-bounces@xxxxxxxxxxxx>



You can ask for 931GB mainstream SSDs. Same price per GB as 15k HDD

El 9 ago. 2018 08:45, "Steinmetz, Paul" <PSteinmetz@xxxxxxxxxx> escribi?:

Jim,

Just curious, why 15K spinny and not SSD.
Cost?
Your performance would be 4x faster with the SSD over 15 spinny.


Paul


-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Rob
Berendt
Sent: Thursday, August 09, 2018 8:31 AM
To: Midrange Systems Technical Discussion
Subject: Re: RAID definition

Doh, forgot about mirroring. We only do that for our VIOS lpars. In their
terminology that would be one 1x1 for one vios lpar and another 1x1 for
the other vios lpar.

283*4 does give you the number quoted. Man, that sure uses up a LOT more
disk than RAID 5 or 6.


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





From: "DrFranken" <midrange@xxxxxxxxxxxx>
To: "Midrange Systems Technical Discussion" <midrange-l@xxxxxxxxxxxx>
Date: 08/09/2018 08:21 AM
Subject: Re: RAID definition
Sent by: "MIDRANGE-L" <midrange-l-bounces@xxxxxxxxxxxx>



Only way that works if if they picked RAID 10.

But I know they picked RAID 10. ;-)

I don't like the way they described this though. They should have said
"10 Drives with RAID-10 with 2 hot spares." Since RAID-10 is mostly
Mirroring, just done at the adapter level, 10 drives means 2 hot spares.
In theory you could just get 9 and save a buck but have a bit less
safety margin if a drive fails.

- Larry "DrFranken" Bolhuis

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

On 8/9/2018 7:33 AM, Jim Hawkins wrote:

We received a quote from our business partner for a new system that

includes

the following:



(10) 283 GB 15K Spinning Disk Drives in two 4 x 4 RAID Arrays w/Hot

Spares

* 1.132 TB Useable



I know what we asked for, but my question to you folks is "how would you
interpret this RAID configuration?"

We asked the BP, but the answer was not informative.



Regards,



Jim Hawkins

Programmer Analyst

Interkal LLC

Kalamazoo, MI

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