Sampling Techdocs - up to May 2014

Here I am again with an overview of interesting TechDocs documents I came across while browsing through the latest publications. If you're completely unfamiliar to Techdocs, here's an introduction to it.

• FAQ : z/OS 2.1 Frequently Asked Question
  This FAQ is a collection of questions that were raised by customers during several presentations on z/OS 2.1 that have been answered by subject matter experts. Too many diverse topics to sum them all up, so just have a look.

• Technical Document : IBM drives to Storage Systems cheat sheet
  I'm sure I mentioned this one before but here's an update on this one-pager showing the currently offered drive types for current IBM Storage Systems including of course DS8000 and XIV.

• Tool : IBM Storage Tier Advisory Tool Charting Utility
  You surely know about the DS8000 Storage Tier Advisor Tool (STAT). Data from the monitoring process by Easy Tier  is included in a summary report that you can download to a Windows system. The STAT application allows you to view the data when you point your browser to that file. Now - on top of this - the Charting Utility does exactly what its name says. This Utility will format some of the data provided and create charts like
• Skew Chart - Workload activity by percentage of capacity
• Movement Chart - Easy Tier data movement activity
• Workload Chart - Capacity utilization by extent pool 

• Technical Document : IBM System Storage Easy Tier Quick Start
  Ok, ok, I'm cheating a bit here, this one is not on Techdocs but I came across it while following a link on the charting utility. "This publication introduces the IBM® System Storage Easy Tier Quick Start, which helps you get started with Easy Tier functions using the IBM System Storage DS Storage Manager". If you have to set up Easy Tier, this is a document you're surely going to like.

Well that's it for now. And, as I always say : just check them out !

DS8870 announcement - Flash optimization II

This is an announcement from last week : 'IBM DS8870 next-generation flash systems deliver high availability and better performance for critical environments (ZG14-0119)'. However last week I was at the IBM Technical University for System z in Budapest and I wanted to have a closer look at the announcement before writing about it. And, by sheer coincidence, this is the first time in my life that I actually saw the real machine before I even read the announcement as we visited the DS8000 plant while in Hungary.

IBM fulfills an earlier statement of direction about the use of a "new high-density flash storage module for selected IBM disk systems, including the IBM System Storage DS8000". Now you might say : didn't they already announce an all flash box last year. Well, yes and no. They announced an all SSD box. Now you may argue again : isn't SSD the same as flash. Well, yes and no. It's more or less the same type of disks, or let's say, flash cards. Let's make a little detour to get a better understanding of this.
IBM has its FlashSystem 840 for open systems which comes from a recent acquisition of Texas Memory Systems. It aims purely at performance and promises extremely high performance and extremely low latency. How does it reach that : well, by concentrating solely on getting the data as fast as possible without any software functionality or storage controller in between that does e.g. compression, deduplication . . . And that's, to me at least, the main distinction between what IBM calls Flash and SSD. As a result the announcement says "it will help to increase IOPS by up to 4 times as compared to SSDs and up to 30 times as compared to spinning drives".

This is realized with new High Performance Flash Enclosures (HPFEs). This "high-performance flash enclosure is directly attached to the PCIe fabric, enabling increased bandwidth and transaction processing capability. The 1U enclosure contains a pair of powerful redundant RAID controllers".

Here's a configuration with just HPFEs in the box.

To the left side, you can see that 4 HPFEs fill the empty slot that was intentionally there from the beginning of the DS8870. ("Intentionally left blank" you might say). One enclosure contains 30 1.8'' flash drives of 400GB giving you a raw capacity of 12TB. If you only use the upper left slot for HPFEs, they can be combined with other types of disks in the regular disk slots.

The box you see here is an "all-flash, single rack system configured with only flash and up to 96 TB of capacity (73.6 TB of usable capacity) in a 8U of space". This all flash box also "provides twice as many I/O enclosures and up to twice as many host adapters as the standard DS8870 single frame configuration" See the extra host adapters in the green square.

Let me also give you a brief summary of the other functionalities that were announced :

• Enhanced Easy Tier® capabilities
  "There are five types of drives managed in up to three different tiers (flash cards and SSDs as tier 0, SAS 15K and 10K rpm drives as tier 1, and nearline drives as tier 2)". Easy Tier also knows the difference in performance within Tier 0 between Flash Cards and SSDs and places the hottest data on the Flash cards.
• 200 GB and 800 GB 2.5-inch FDE SSD drives
  New drives next to the 400GB drives
• Concurrent code load enhancement
• Warmstart enhancement
• Multiple Target PPRC with limited availability
• OpenStack support : "DS8870 offers full support for OpenStack releases Havana and Icehouse. Support is provided through the OpenStack Cinder driver". For the moment this is not z/OS related but read my previous post on OpenStack to understand the value of it. It creates a framework to automate storage provisioning and volume management and to simplify deployment and make DS8870 capabilities available for cloud environments.

General availability : June 6, 2014. Some field availability is only in September.

Easy Tier - what you might not know about Auto Rebalance

I thought I knew quite a lot about DS8000 and Easy Tier but last week I had the opportunity to meet Stephen L. Blinick who works at the DS8000 labs in Tucson. Stephen is closely engaged in the development of the DS8000 box. And he's a great presenter who (obviously) knows what he's talking about.

There was one aspect about Easy Tier Stephen told me of which I was completely unaware. I should have known because this is somethning really important about Easy Tier and its Auto Rebalance feature. As the Redpaper 'IBM System Storage DS8000 Easy Tier' states : "The auto-rebalance capability automatically rebalances the workload even across the physical resources within a drive tier, reducing the occurrence of hotspots".

So, as you see below this is a situation within a drive tier where Easy Tier detects some hotspots.

 It rebalances the workload across all ranks.

By doing so, auto-rebalance reduces performance skew within a storage tier and provides the best available I/O performance from each tier.

But there's more and here comes the interesting part of the story. You know how it's always so annoying when you add additional ranks to the pool. Everything is well balanced within the existing ranks but you have to put new workload just on the new disks or you have to rebalance everything manually. NOT SO with Easy Tier.

"Auto Rebalance also automatically populates new ranks that have been added to the pool when rebalancing the workload within a tier. Starting with DS8000 R6.2 LMC, auto-rebalance can be enabled for hybrid and homogeneous extent pools".

Great ! Isn't it ? Check out the Redpaper if you want to know more about this great feature.

Announcement : DS8870 Release 7.1

Today there were two announcements for the DS8870. One on hardware : 'IBM System Storage DS8870 (machine type 2421, 2422, 2423, and 2424) delivers advanced Easy Tier capabilities, enhanced resiliency, and business continuity functions (ZP13-0060)' and one on related software functionalities : 'IBM System Storage DS8870 (Machine type 2396, 2397, 2398, and 2399) Function Authorizations for advanced Easy Tier Server capabilities (ZG13-0055)'.

Apart from every one putting more and more focus on Flash, I think a large part of this announcement is about Easy Tier V5. But not everything applies to System z. The first feature is only applicable to Power systems : Easy Tier Server, which allows to copy some of the hottest data to SSD disks on the Power server. These SSD disks serve as a cache and should give you much faster response times by overcoming latency of the SAN. This remains of course managed by Easy Tier itself.

Easy Tier Application gives the administrator some influence over the Easy Tier automatic processes as he can sort of overrule them for specific cases. It "is an application-aware storage application programming interface (API) to help deploy storage more efficiently through enabling applications and middleware to direct more optimal placement of data by communicating important information about current workload activity and application performance requirements. In this release, the new Easy Tier Application feature also enables clients to assign distinct application volumes to a particular tier in the Easy Tier pool, disregarding Easy Tier's advanced data migration function". It also gives better insight in the working of Easy Tier.

The Easy Tier Heat Map Transfer utility "is able to provide whatever the data placement algorithm is on the Metro Mirror/Global Copy/Global Mirror (MM/GC/GM) primary site and reapply it on the MM/GC/GM secondary site(...). With this capability, DS8000 systems can maintain application-level performance at an application secondary site when it takes over in supporting a workload after a failover from the primary to secondary site". The last two features are of course platform independent.

What else ? I won't sum up everything but I just want to mention two other things

• Prevention of accidental loss of data when initializing a z/OS volume with ICKDSF INIT or REFORMAT. Ability to determine what z/OS Systems a volume is online to.
• There's a low cost entry class configuration option which comes down to more drives per device adapter

The software announcement is about the Function Authorizations which "are for billing purposes only". The new function which is introduced is for the Easy Tier Server function : IBM System Storage Easy Tier Server indicator (feature number 7084).

And for all the rest of the goodies ? Well, just check out the announcements ?

Sampling Techdocs - June-August 2011

Here we are with some new documents from TechDocs I recently came across or found while browsing through the latest publications.

• Presentation : Why Websphere Application Server for z/OS
  Starting point of this presentation is : "Websphere is Websphere" no matter what platform you run it on. But is that really so ? No, not at all. Websphere Application Server for z/OS is very aware and is using the underlying platform to a considerable extent. So, there might be a couple of reasons why you would specifically want to use WAS for z/OS . . . So, read on, here they are.
  
  
• Presentation : z114 Hardware Management Console 2.11.1
  "The 2.11.1 Traditional Hardware Management Console (HMC) is new with the z114 Server. This presentation covers the enhanced features and functions of the 2.11.1 Traditional HMC which is available at Driver 93 for both the z196 and the new z114".
  
  
• Technical document : DS8000 EasyTier Implementation Guide
  This is a DS8000 EasyTier Implementation Guide Using DSCLI with examples. Subjects discussed are Easy Tier Overview, Easy Tier implementation using DSCLI, DS8000 Logical configuration, Data Relocation with Easy Tier Automatic Mode and with Easy Tier Manual Mode.
  

• Flash : IBM zEnterprise BladeCenter Extension Top of Rack Switch (TOR)
  New technology usually comes along with lots of new terminology as well. Well, it's not different with the zBX and here you'll find two documents explaining everything about the Top of Rack Switch and the connectivity with the mainframe.
  

• FAQ : Frequently asked questions from IBM and Oracle customers about Linux on IBM System z
  Nice FAQ that "answers a few common questions about Oracle products running on IBM System z running Linux. This document was jointly written by IBM and Oracle". Subjects are Oracle product availability on the System z platform, Oracle Grid and IBM System z and Technical Support.

• Referral pages :
  I'm concluding with some classics that keep getting updated every once in a while.
  First there's 'Withdrawal of z/OS Function Beginning with z/OS Release 5 Through Current z/OS Release'. "This flash lists those items IBM has announced intention for removal in a specific z/OS release. These items have already been announced in previous IBM z/OS announcement letters. Consideration should be given to this list when planning your migration to a z/OS release".
  The second is the 'IBM System z I/O Feature Reference Table'. This table provides information about System z I/O features and the specific machine types on which they are supported. It is grouped by card type / function: OSA, FICON, Parallel Sysplex, Cryptography, ESCON, and I/O Support.
  The last one is the 'IBM Mainframe Life Cycle History' : System z mainframe hardware product marketing and service life cycle history since 1994.
  

Well that's it for now. As I always say : just check them out !

May 9 - DS8000 announcements

Monday, there were two announcements for the DS8000 (ZG11-0130, ZG11-0131). General availability of the announcements is June 3, 2011. DS8000 by now means DS8700 and DS8800.

Same functionality with Release 6.1
Despite the known differences (Power 6 vs Power 6+ engine, 2GB/s device adapters vs 8Gb/s and 3.5'' FC drive interface vs 2.5'' SAS-2 drive interface), they are now brought at the same functional level with one another. This means that some functionalities become available on the DS8800 as well. These include :

• Easy Tier
• Thin Provisioning
• Remote Pair FlashCopy
• z/OS Distributed Data Backup
• z/OS FICON Discovery and Auto Configuration (zDAC)
• Eight drive install groups of Solid State Disk (SSD)
• z/HPF extended distance
• . . .

On the other hand the DS8700 also gets the 8Gb/s host adapter.

Easy Tier V2
The most eye-catching change is that the Easy Tier automatic mode now supports migration between any two tiers. You no longer need SSD drives to make use of the Easy Tier automatic possibilities. Some other capabilities that come with Easy Tier V2 :

• Cold demotion - Inactive "cold" data stored on Enterprise performance Tier is demoted to a more appropriate tier.
• Warm demotion - When a specific rank in the higher tier exceeds its optimal performance level, selected extents are moved to other ranks to eliminate the growing hotspot.
• Auto-Rebalance - Easy Tier automatic mode redistributes extents within a tier whenever it shows I/O skew, when new capacity is added or when capacity is removed.

By the way : Easy Tier remains a no-charge feature.

I/O Priority Manager
I/O Priority Manager on the other hand is a priced feature and is only available for open systems.
"The system will prioritize access to system resources to achieve the volume's desired quality of service based on defined performance goals (high, medium, or low) of any volume. I/O Priority Manager will constantly monitor and balance system resources to help applications meet their performance targets automatically, without operator intervention." This only happens when there's a contention between multiple volumes. I/O Priority Manager delays the right amount of I/O from lower priority volumes, so higher priority volumes get more throughput.

Storage Manager GUI
The XIV GUI seems to be a real success as the DS8000 Storage Manager is now also aligned with the same GUI. "The enhanced design was inspired by the IBM System Storage XIV® GUI and includes more intuitive navigation panels and streamlined configuration processes, as well as embedded links to relevant videos for quick access to useful DS8000 information".
For more information about this GUI, take a look at the 'Simplify the Flightdeck' post at the Aussie Storage Blog.

In addition to that, there is also some enhancements for security, copy services an large LUNs for open systems.

Easy Tier Manual Mode without SSD drives ? Yes you can !

I was very disappointed last week to find out that the Easy Tier Manual Mode for the DS8000 really required the hard presence of some actual SSD drives even if you only wanted to perform some operations on HDD drives. So I wrote the following post about it : 'Easy Tier Manual Mode without SSD Drives ? No Way' to tell the customers I'd been telling them some lies.

I checked this, double checked this and then posted it as I had no access to a DS8700 to test it myself. I must say I kind of hoped some one would reply to contradict this. And you know what : I had two replies from IBM people telling me you CAN use Easy Tier Manual Mode without any SSD drives present. So Nick Clayton comments :

It is possible to use the Easy Tier manual migration function without having SSD drives installed. You do however have to have requested the zero charge Easy Tier feature to do this.

And Anthony Vandewerdt confirms this

I can tell you that I have used the manual mode method on a DS8700 with NO SSD and it worked just fine.
All you need are the R5.1 code level installed and the EasyTier license key (which is a $0 key).
Once both those things are true, manual mode (rebalancing vols and merging extent pools) is possible regardless of whether SSD is present or not.

I'm glad it is possible after all because even the Manual Mode is actually a great feature. By the way, Anthony's changed his blog address. It's now at Wordpress and it's called : Aussie Storage Blog. Do check it out !

Easy Tier Manual Mode without SSD drives ? No way !

Update : this post has become obsolete.
I'm not deleting it because the comments contain valuable information.
Check out my update : Easy Tier Manual Mode without SSD drives ? Yes you can !

I'm not exactly sure how I should begin this post. I might say something like : I must apologize to all our customers to whom I explained Easy Tier for not telling the truth. Or perhaps : damn, I hate some of those IBM announcements for only telling half of the story. Mind you, there are no lies in these announcements, but they're not telling everything, they leave out things and people tend to try and fill in the blanks for themselves. That's exactly what I did with Easy Tier on DS8000.

You know there's an Automatic and a Manual mode. Well, for the Automatic mode you need to have SSD drives. That's the whole point of using Easy Tier in automatic mode, making sure the most accessed data are put on the SSD drives.

But then, there's the Manual mode. What is it for ? I'll just quote what I wrote about it when it was first announced :

"Volume migration - Enables the manual relocation of volumes between extent pools, as well as the restriping of volumes within an extent pool, and the ability to merge existing extent pools".
You don't even have to have SSDs installed in order to use Easy Tier functionalities. The second feature operates at volume level. "Easy Tier also includes the ability to dynamically relocate individual logical volumes to another drive tier or to another drive type within a tier. For example, clients can move a volume from a set of 15,000 RPM spinning drives to a set of 10,000 RPM spinning drives. In addition, they can also change a volume’s RAID type from, say, RAID 5 to RAID 6, as well as change the way data is striped within the system. For instance, a volume that was configured to stripe data across a single RAID array can be changed to stripe data across multiple arrays for better performance. And all of this can be done dynamically without disrupting applications."

I put one specific sentence of mine in bold because it is absolutely NOT true. Even for Manual Mode you do have to have at least some SSD drives into your DS8000. This is the official answer I received from IBM TechLine. I really thought you didn't have to and no one has ever told me you did. This is what always bugs me : the announcement doesn't mention this SSD requirement, so you start thinking things, filling out the blanks. Well, you shouldn't. What isn't there, isn't there for a reason . . . And Easy Tier without SSD drives just isn't there.

Two white papers on DS8700 and Easy Tier

I wanted to mention these two documents in one post as they are sort of related. The second one however didn't show up on Techdocs until last week.

The first one is titled 'IBM DS8000 Storage Virtualization Overview Including Storage Pool Striping, Thin Provisioning, Easy Tier' and it was already published in 2009. But, now it's been largely enhanced covering subjects like Storage Pool Striping function, Thin Provisioning facility, Quick Initialization function, Easy Tier facility. It really gives you a great introduction and lots of practical information on all of these topics. And do not immediately associate Easy Tier with SSD only. You can also already do great stuff with the Manual Mode.

The second one is 'IBM System Storage DS8700 Performance with Easy Tier'. As you can see, this is specifically concentrating on Easy Tier (unfortunately DS8700 only). It discusses performance with automatic and with manual Easy Tier modes. And it also discusses the use of the Storage Tier Advisor Tool. So, you can already ask yourself the 'What If' question : what if I had SSD installed. What would be the performance boost for me ?

So, two documents definitely worth checking out if you're even only remotely interested in Easy Tier. And while I was browsing through Techdocs, I also found this presentation on Easy Tier which was only added last Tuesday : 'Accelerate with ATS: Easy Tier Webinar'. No audio for the moment, but it will perhaps be added in the coming days.