RE: Power 9 disk config

My question is do you need to control what goes to SSD and what goes to SAS, and how if so, how will you control that?

Paul

-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of DrFranken
Sent: Thursday, September 13, 2018 10:57 AM
To: Midrange Systems Technical Discussion
Subject: Re: Power 9 disk config

I WILL say this is the first time I have every seen this configuration.
We don't see a lot of RAID 10 but it DOES have one advantage in that
there is one write to the RAID 10 set which in turn writes to two
drives. Compare this to IBM i mirroring where IBM i would do a separate
write to each drive of the mirrored pair.

With these two sets as suggested you will have one 'owned' by each of
the SAS controllers in the system so that's good for performance.

I am not seeing any huge red flags here for a small system.

Unknown details of course such as are they turning up all four cores and
expecting to blast a ton of I/O? Or is this a basic system with one
core, perhaps 32GB of memory and they just want SSDs in there to add a
bit of 'gofaster' to the system.

- Larry "DrFranken" Bolhuis

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

On 9/12/2018 7:47 PM, Don Brown wrote:

I am configuring a new power 9 for a customer a 9009-41A

This system has a maximum of 10 internal drives.

Requirement is for;

4 x 931GB SSD in RAID10
4 x 283GB SAS in RAID5

I am trying to determine if there is a possibility of a performance issue
between the two raid sets ?

My concern was raised when I got an email from IBM with "You will not get
any performance guarantees!"

Customer is requesting the SSD's in RAID10.

I know there are a number of BP's on this list - any comments on this disk
config ?

Thank you



Don Brown