In recent articles in this series I’ve been looking at the architectural choices for building All Flash Arrays (AFAs). I surmised that there are three main approaches:
- Hybrid Flash Arrays
- SSD-based All Flash Arrays
- Ground-Up All Flash Arrays (which from here on I’ll refer to as Custom Flash Module arrays or CFM arrays)
I’ve already blown metaphorical raspberries at the hybrid approach, so now it’s time to cover the other two.
What’s the most important attribute to consider when you want to buy a new storage system? More critical than performance, more interesting than power and cooling requirements, maybe even more important than price? Whether it’s an enterprise-class All Flash Array, a new drive for your laptop or just a USB flash key, the first question on anybody’s mind is usually: how big is it?
Yet surprisingly, at least when it comes to All Flash Arrays, (more...)
How do you monitor an ZFS Storage Appliance with Oracle Enterprise Manager 12c? This is a question that has been asked a few time and I needed to solve this issue. You hear a lot about the em agents and that they need to be used to monitor many different targets. Let’s just say, that is not the case when wanting to monitor a ZFS Storage Appliance.
In order to monitor a ZFS Storage Appliance, (more...)
In the previous post of this series I outlined three basic categories of All Flash Array (AFA): the hybrid AFA, the SSD-based AFA and the ground-up AFA. This post addresses the first one and is therefore aimed at answering one of the questions I hear most often: why can’t I just stick a bunch of SSDs in my existing disk array?
Data Centre Dinosaurs
Disk arrays – and in this case we are mainly talking about (more...)
Almost exactly a year ago I published a post covering my first impressions of the ASM Filter Driver (ASMFD) released in Oracle 220.127.116.11, followed swiftly by a second post showing that it didn’t work with 4k native devices.
When I wrote that first post I was about to start my summer holidays, so I’m afraid to admit that I was a little sloppy and made some false assumptions toward the end – assumptions (more...)
For the last couple of years I’ve been writing a series of blog posts introducing the concepts of flash-memory and solid state storage to those who aren’t part of the storage industry. I’ve covered storage fundamentals, some of what I consider to be the enduring myths of storage, a section of unashamed disk-bashing and then a lengthy set of articles about NAND flash itself.
Now it’s time to talk about all flash arrays. (more...)
So this is it – the last article in my mini-series on understanding flash. This is the bit where I draw it all together in a neat conclusion that makes you think, “Yes! That was worth reading”. No pressure eh?
So let me start with the conclusion first: as a storage medium, NAND flash is a royal pain in the ass.
Why? Well, let’s look back at what we’ve learned in the previous 9 (more...)
This is a very simple post to show the results of some recent testing that Tom and I ran using Oracle SLOB on Violin to determine the impact of using virtualization. But before we get to that, I am duty bound to write a paragraph of text featuring lots of long sentences peppered with industry buzz words. Forgive me, it’s just the way I’m wired.
It is increasingly common these days to find database environments running (more...)
I’ve run into a few customers recently who have had problems with their ASM rebalance operations running too slowly. Surprisingly, there were some simple concepts being overlooked – and once these were understood, the rebalance times were dramatically improved. For that reason, I’m documenting the solutions here… I hope that somebody, somewhere benefits…
1. Don’t Overbalance
Every time you run an ALTER DISKGROUP <NAME> REBALANCE operation you initiate a large amount of I/O workload as (more...)
Vanuit Proact organiseren wij het kennisplatform SYNC 2014 op 17 september in de Rotterdam Cruise Terminal. Alle hedendaagse IT-infrastructuurontwikkelingen in 1 dag:
• Een interactief programma o.l.v. dagvoorzitter Lars Sørensen o.a. bekend van BNR
• Een keynote van Marco Gianotten van Giarte, de Nederlandse “Gartner” op het gebied van Outsoucing/Managed Services
• Huisman Equipment over de
In this post I want to show how to test what will happen with your cluster if you simply detach shared storage device from it. VirtualBox is great tool for that purpose because you can test such scenario without involving many people or causing any damage.
I am aware that (more...)
Last week I had a lengthy post at oracle-l that tackles Calibrate IO, Short Stroking, Stripe size, UEK kernel, and ASM redundancy effect on IOPS Exadata which you can read here
followed by interesting exchange of tweets with Kevin Closson here (see 06/21-22 tweets) which I was replying in between games at UnderwaterHockey US Nationals 2012 which we won the championship for the B division I have my awesome photo with the medal here
This post will detail on the ASM redundancy/parity effect on IOPS… if… by changing the ASM redundancy (external, normal, and high) will it decrease the workload (more...)
On my post about observing the Exadata V1 I had an interesting comment posted by Mark Seger (author of collectl and collectl utilities) about the correlation of activities across a system, the sample and snap time, and seeing the state of the subsystem before and after…
The comment made me curious about the effect of snap intervals on the performance numbers of the datafiles and block devices.. especially on the latency numbers.. so I made a few test cases and created some scripts that would give me 5 seconds, 10 minutes, and 60 minutes output of (more...)