cloud

Storage Tiering in the Cloud? Just some thoughts…

Duncan Epping · Apr 26, 2010 ·

When discussing design considerations for a Cloud environment there are always a few “hot” topics. Two of these usually stand out: Network and Storage.

This is not only the case with Cloud environments but with virtualization in general. I guess where Cloud differentiates itself from a regular virtual environment is storage tiering. A simple reason to implement storage tiering is cost. Running every virtual machine on the same storage is not very cost effective and will ultimately increase the prices per unit, whether that unit is a VM or consumption model based is not even important at this point.

Many storage vendors offer an automated storage tiering concept. These typically migrate virtual disks or “blocks” based on load pattern. This might be a viable solution for your enterprise environment but is that also the case for a Cloud provider? Or better said for the customers running their workload within the Cloud?

Would you want your virtual disks, or blocks, to be migrate when the storage subsystem of your provider feels it should? Or would you prefer a predictable performance? I guess I am hoping that you, as possible customers, could answer this question. Personally I prefer to get what I paid for. If I have paid for raid-5 on 15.6K disks I want to be able to use that performance when my application requires it.

Now you might say, well with the auto migration mechanism Arrays have these days you will be on fast storage before you know it, but is this actually the case? (Think EMC’s FAST, Compellent’s Data Progression or 3Par’s Adaptive Optimization) Many of these mechanisms will move data around when a threshold has been exceeded within a specific time frame. This might be too late, your job might have already completed. Now I am not, most definitely not, an expert on automated storage tiering, but I wonder who will benefit and when in the Cloud space? Maybe even more important, what if my mechanism chooses to move me to fast storage… will my Cloud service provide bill me for this?

I know I am not answering any questions here and I guess this is one of those posts which rises more questions… I would like to open the floor to anyone who wants to share his thoughts.

Want to be part of the vCloud Team?

Duncan Epping · Feb 26, 2010 ·

If you are based in EMEA and are up for a challenge you might want to check out the following job roles as the VMware vCloud Services Team is still looking for highly motivated and skilled people! Just drop me (duncan @ yellow-bricks.com) an email when you are interested and I will make sure your resume will end up in the right spot!

Senior Engagement Project Manager -TS Cloud Services
As a VMware Cloud Services Engagement Program Manager within the Cloud Services team, you will be acting as a thought leader for a specific segment of Cloud Service Providers as well as Enterprise accounts developing on-premise clouds. You will manage VMware Cloud services engagements, have strong contacts within the accounts you support, and support the sales teams building pipeline for the customer segment for which you are responsible.
Senior Engagement Project Manager -TS Cloud Services
As a VMware Cloud Services Engagement Program Manager within the Cloud Services team, you will be acting as a thought leader for a specific segment of Cloud Service Providers as well as Enterprise accounts developing on-premise clouds. You will manage VMware Cloud services engagements, have strong contacts within the accounts you support, and support the sales teams building pipeline for the customer segment for which you are responsible.
Consulting Architect-TS Cloud Services
As a VMware TS Cloud Services Architect, you will provide customers technical leadership in the installation, configuration, and implementation of VMware-based cloud solutions. You will help to document best practices in developing and deploying VMware solutions, and feed them into our knowledge base for best practices by customers and partners. This group gives the architect the opportunity to work in most of the top Fortune 500 companies in the world.
Senior Consultant-TS Cloud Services
As a VMware TS Cloud Services Consultant, you will provide customers technical leadership in the installation, configuration, and implementation of VMware-based cloud solutions. You will help to document best practices in developing and deploying VMware solutions, and feed them into our knowledge base for best practices by customers and partners. This group gives the consultant the opportunity to work in most of the top Fortune 500 companies in the world.
Senior Consultant-TS Cloud Services
As a VMware TS Cloud Services Consultant, you will provide customers technical leadership in the installation, configuration, and implementation of VMware-based cloud solutions. You will help to document best practices in developing and deploying VMware solutions, and feed them into our knowledge base for best practices by customers and partners. This group gives the consultant the opportunity to work in most of the top Fortune 500 companies in the world.
Senior Consultant-TS Cloud Services
As a VMware TS Cloud Services Consultant, you will provide customers technical leadership in the installation, configuration, and implementation of VMware-based cloud solutions. You will help to document best practices in developing and deploying VMware solutions, and feed them into our knowledge base for best practices by customers and partners. This group gives the consultant the opportunity to work in most of the top Fortune 500 companies in the world.
Senior Consultant-TS Cloud Services
As a VMware TS Cloud Services Consultant, you will provide customers technical leadership in the installation, configuration, and implementation of VMware-based cloud solutions. You will help to document best practices in developing and deploying VMware solutions, and feed them into our knowledge base for best practices by customers and partners. This group gives the consultant the opportunity to work in most of the top Fortune 500 companies in the world.

Not al compute units are equal

Duncan Epping · Jan 14, 2010 ·

I was just reading an article which is titled “Surprise! Not all Amazon EC2 compute units are created equal. I think it’s a very interesting article and actually shows how people think/feel about what cloud computing is offering. In this case it’s all about the perception and as with many users the perception of performance and the misunderstanding of the technology that is driving this. The following quote from the article linked above captures the essence of the story

It turns out that the underlying hardware for each instance created impacts the actual performance that each instance gives you, even though the instances are all virtualized and marketed by Amazon as if they are all created equal. In our case, we found that the different underlying hardware that the virtual instance sits on has a significant impact on application performance, at least with respect to MySQL database performance. Instances that were created on machines with AMD’s Opteron 270 processors (2ghz 1mb L2 cache) showed significantly poorer MySQL performance compared to instances created on machines with Intel’s Xeon e5430 processors (2.66ghz 6mb L2 cache).

Now after reading this a lot of you may say “DUH”. Of course you can’t expect this be to be equal, but when reading Amazon’s explanation of a Compute Unit I do understand where this comes from.

Source
EC2 Compute Unit (ECU) – One EC2 Compute Unit (ECU) provides the equivalent CPU capacity of a 1.0-1.2 GHz 2007 Opteron or 2007 Xeon processor.

Cloud Computing, as Mike D. has explained many times already, is about the end-user not caring about what lays underneath as long as it meets there business requirements(non technical). Or in other words, and I quote “I don’t care”.

However as you can clearly see in the quote above, and please read the full article, the end-user does care when it comes down to performance. Performance needs to be guaranteed but more surprisingly equal in all cases. In the case mentioned above a single server had better(!) performance then guaranteed by Amazon and still the customer was dissatisfied with it as it clearly skewed expectations.

What can we do to prevent this and should we try to prevent this or create a better explanation of what “Compute Units” are. I actually don’t think there’s a single correct answer to the question or even a solution at this point in time as we are still growing and maturing. I will leave it at that for now and let the topic sink in, if you do have an answer please speak up.

While I was writing this article I was pointed by @MattPovey(EMC) to another article titled “Has Amazon EC2 become over subscribed?” Which is an excellent read and also deals about performance and the perception of just that. I think the key take away is that the user, when one of the few virtual instances using a physical server, sees a decline in performance over time. Although Amazon might still meet the SLA it is the users perception that performance decreased and are not equal to what has been offered.