Accelerating VAAI

This post originally appeared on Juku but I find it technical enough to be featured in my personal blog

By now everyone and his dog already made a post about VAAI, I would not bother you with an extensive explanation of what is VAAI and why it’s crucial to Virtualization, I will simply refer to a couple of posts that explain its current implementation in details:

• Duncan Epping
• Bas Raayman
• Chad Sakac

My focus will be on how I envision to accelerate VAAI even more, enhancing its storage side.

To explain my point of view I will do an analogy with a common feature found in storage arrays today: Point-in-Time Copies.

Point-in-time copies (sometimes referred to as Snapshots) are a really valuable feature, they provide a consistent point in time of a specified Data set in order to perform various tasks like: backups, environment duplications and so on.

Traditionally PIT copies were made using a technique called Copy-On-Write which is suitable for a small number of PIT for a single LUN but its performance issues take their toll as soon as their first PIT is created, PIT copies concept was pioneered by IBM with its FlashCopy functionality.

NetApp innovated the approach to PIT copies using a different pointer-based snapshot technique, this almost completely eliminated the performance issue and made possible a massive number of multiple snapshots per single LUN enabling the complete potential of the PIT concept, this post explain how the Compellent Storage Center pointer-based snapshots works in detail, however this is not specific to Compellent, almost all the next-generation storage arrays (like IBM XIV, NetApp FAS, 3Par InServ, Dell Equallogic, HP Lefthand and many others) use the same approach.

So basically we have a great concept (PIT copies) but with most of its potential still locked by its implementation (Copy-on-Write) and then we have an innovator that enable its full potential with a clever implementation and I’m pretty sure that VAAI is still in its “Copy-on-Write” stage of life .

As you already know VAAI is implemented using an extended SCSI command set, Let’s take as example the most sought-after feature: the Hardware Offloaded Copy.
The hardware offload copy in my opinion can be accelerated to 100000x making all the cloning tasks a matter of few seconds, here’s how:

Keep in mind how a pointer-based snapshot works and bear with me with my explanation:

A 16GB VM sitting in a 128GB Datastore is currently accessed by an ESX host.

Then a VAAI-enabled Clone request is issued by the host, the storage array, instead of doing a real block-to-block copy, simply create a “map” of pointers of the cloned VM on another portion of the datastore, locking its space but without issuing a single block copy, this operation should take the same time as a normal snapshot: few seconds.

Then the host start to write to the new cloned VM and the delta differences are stored in the blocks locked by the “map” previously created.

A similar task can be already done today using snapshots, but it becomes cumbersome immediately because every clone needs to reside on its own LUN and datastore, this approach, instead, can be applied “inside” a datastore streamlining the deployments. Just imagine a VDI infrastructure relying on such cloning technique! .

I’m sure that storage vendors will try to integrate and innovate their respective VAAI implementations, I hope this post made you realize how powerful can be the still-evolving VAAI approach.

Technorati Tags: virtualization, VMware, VAAI, storage

My new blogging effort: Juku.it !

It’s been a long time since my last post, as you may already know I’ve been very busy obtaining the VCDX certification and I’ve been also knee deep in getting a new blog online: Juku.it

Me and Enrico decided to convey our blogging effort into a more open and agnostic form, without being tied to a specific vendor (I work as Architect at a small consulting firm called Cinetica) and so Juku was born, as told in the “Why Juku?” section Jukus are private Japanese schools and they’re intended to help students improve performance in their regular school work and to help them better prepare for exams, and that’s precisely our goal, not to replace the traditional information channels, but to augment them with our opinions in the more unbiased manner possible.

I will continue to post the more technical articles and my personal thoughts on P2V It! so don’t just unsubscribe it

Technorati Tags: virtualization, juku, blogging, storage

VCDX #58

So I finally made it, on Friday night I received an email from Melissa of the VCDX certification team stating:

Congratulations!  You have achieved the VMware Certified Design Expert on VI3 (VCDX3) certification.

Your VCDX number is:  VCDX58

I exploded with a scream of joy, I felt a mix of relieve, excitement and proudness, I really couldn’t believe that I made it.

I already wrote about my Defense experience in a previous post, I have nothing to add to it so I will just thank everybody who supported me through this journey, especially my wife, @esignoretti, @Andrea_Mauro, @drakpz and all the other guys on twitter!

This is truly the most difficult and rewarding achievement in my whole professional life, I wish the best of luck to everyone who will defend at PEX 2011 which will also be the last chance to become a VCDX on VI3.

Technorati Tags: travel, VMware, vcdx, virtualization

My own VCDX Defense experience

So today was my day, I spent the whole monday studying my materials like a recluse in my hotel room (my wife had an extra reserve of patience to burn , Today I woke up at 5:00am in order to prepare myself for the defense, I took a shower to clear my thoughts, had a quick breakfast and then drove from Burlington to Alewife to catch the T red line to Kendall, where the VMware offices are located.

I was a bit pessimistic about public transport (well, I’m used to those in Italy) so I ended up being very early (7.25am) to the appointment, I left my wife with a good book to read and I started rehearsing my initial presentation, at 8:05 they made me walk into the Panel room where I hooked up my Mac to the projector and the (in)famous iPad timer started running…

Everything is under NDA so I cannot disclose the questions, and I will not disclose who was on my Panel too (they can do that if they want) but it definitely was intense, unfortunately my spoken English is quite bad so I had to try to explain myself with simple articulations, I still don’t know if they were effective, definitely I was not satisfied with them.

The 75 minutes flew thru like they were 5, and if you normally don’t believe what you read on the internet about stuff, this is definitely not the case, BELIEVE everything they say about the VCDX defense.

After the defense I got 15 minutes to spare, I had some tea, visited the men’s room, checked out the stunning Boston panorama (the VMware offices are located on the 10th floor) and relaxed myself on the overly comfortable armchairs in the cafeteria, believe me, they were the most refreshing 15 minutes I ever had in my whole life.

After the break I walked into the room again for the Design and Troubleshooting part, obviously I can’t go into details here, I will just say that I was probably on the right track for the Design but I spent too much time on two things only, If I had to retry this I would have done things differently.

The troubleshooting scenario is the one that I was most confident with, I think I found the root cause and hope that my explanation of the problem was enough verbose and correct.

Now they’re going to let me know the outcome on Friday the 12th (or even Monday the 15th), I will eagerly wait for that email, in the meantime I still feel a sense of relief

For the VCDX candidates still having to defend here’s an advice that I quote from the great Jason Boche:

Tips for the Defense:

1) Know your design, I mean really know it.

2) Refer to tip #1

This is definitely the wisest advice.

Technorati Tags: travel, VCDX, VMware

VMworld Europe 2010 – Wrap Up

(the photo shows @BasRaayman, Me and @VMdoug, in order of appearance)

So VMworld Europe has come to an end, sadly this kind of events are always shorter than expected, but I’ve been lucky enough to meet a lot of interesting people and fellow tweeps.

I enjoyed many sessions, my favorite surely was BC7803: Planning and Designing an HA Cluster that Maximizes VM Uptime, presented by Duncan Epping and Marc Sevigny, this session covered many advanced aspects considered when designing HA clusters in simple and even complicated scenarios, like stretched campus clusters, very interesting.

Another session that I enjoyed was TA7805 Tech Preview: Storage DRS by Irfan Ahmad which is a cool guy and a great presenter (I didn’t fall asleep even if I was in a post-lunch coma ) showed a really cool new feature that can literally disrupt what we do today to ensure storage fairness.

But the killer feature of VMworld this year were the hands-on labs, as I mentioned in a previous post, all the labs were hosted on the “Cloud” which was physically located across the Atlantic in Florida and Virginia (more information about the labs can be found here). All the labs were delivered via Wise Thin Clients using the PCoIP protocol, I completed several labs and never experienced a delay, the end user experience was awesome. Also it’s worth mentioning that every Lab was provisioned using virtualized ESX servers which is just plain cool! (and make me proud of my discoveries on how to run a virtualized ESX 3 back in 2007).

I also hung around the Blogger Lounge and had a quick chat with @plankers (which incidentally runs one of my favorite blogs: The Lone Sysadmin) and the one and only @BasRaayman (who is now part of the vSpecialist army), met the vNinja @h0bbel who took A LOT of pictures during the event (including the one featured in this post). I shook hands with @DuncanYB and @FrankDenneman (if you lived under a rock until today, they’re two of the most respected Virtualization Gurus around) and met a huge amount of Italian people interested in Virtualization, this meeting has sparked the creation of an Italian chapter of the VMware User Group, we created a LinkedIn Group and more than 70 people already subscribed to it.

We’re facing interesting times, let’s see what happens next

Technorati Tags: VMware, VMworld, VMworld Europe