You can not base your arm count on capacity only. You also need to look at how many IOPS you need to support for each of those environments. If you are going to look at PROD hosting DEV, then you need to combine the IOPS to properly size the number of arms needed in PROD. More than likely you will end up with much more capacity than your installed system, mainly because the smallest drive size is larger than your installed drives.
If your requirements fit within 64GB memory and 4-cores of IBM I, then you can look at the S914/S814 (P05 tier) with a v5020. Direct connect via fiber (No switches required) will support 1 or 2 LPARs. More LPARs you will need switches and dual VIOS. With the v5020 you can use Easytier to automatically more data between SSDs and HDDs much better than you can with internal IBM I disk. The cost is very reasonable plus you get additional benefits like flash copy. How would you like to be able to make a backup copy of your disk before an OS upgrade/application upgrade/PTF just incase things go south. A Flash Copy takes 1 minute.
From: Rob Berendt<mailto:rob@xxxxxxxxx>
Sent: Tuesday, October 23, 2018 12:58 PM
To: Midrange Systems Technical Discussion<mailto:midrange-l@xxxxxxxxxxxx>
Subject: Re: New system configuration
In your situation I really question whether SSD's (even for load source)
are worth the price and maintenance. With the newer system you'll be
impressed enough.
You are hitting the usual stuff when people upgrade infrequently. Disk
sizes have grown so much that estimating size needed for a small system is
outweighed by arms needed. I would shoot for six arms of currently
marketed 15k spinning disks (and stay away from the 'archive' models of
10k speed).
So what is the current minimum size of currently marketed spinning disks?
280GB, or are they still selling new 140's?
Keep in mind that with RAID5 you lose one drive to raid striping.
So (six drives - 1 drive to raid striping) * 280GB = 1.4TB
I would not go with less than four drives under any circumstance. I would
really shoot for the 6 drives and only bring up the possibility of less if
it's a deal breaker.
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: "Kevin Bucknum" <Kevin@xxxxxxxxxxxxxxxxxxx>
To: "midrange-l@xxxxxxxxxxxx" <midrange-l@xxxxxxxxxxxx>
Date: 10/23/2018 12:25 PM
Subject: Re: New system configuration
Sent by: "MIDRANGE-L" <midrange-l-bounces@xxxxxxxxxxxx>
To start with - thanks everyone that has chimed in. I really appreciate
the help this list provides.
Dev is 256 gigs right now, and we will probably double that in the new
setup. I guess the question becomes can we get enough capacity running at
a fast enough speed with enough arms in the main enclosure. Production is
only 1702 gigs right now. Currently we have 6 slots in the cec on our 550.
Those are running 3 mirrored pairs. One each for dev, vios, and the linux
partition. Production is in it's own enclosure. I want as much disk
running as fast as I can get it, but I don't have to pay for it. The guys
who do want as much performance at the lowest cost they can get. Getting
the balance right is important as we don't get new boxes often. We have
had the current one for 10 years, and the new one will be the third box
since I started working here in 2001.
midrange.com
