Virtualization and HA, Scalability
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@scottalanmiller we had to use them for the presentation but that done i think anyway
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@kelsey said in Virtualization and HA, Scalability:
@scottalanmiller we had to use them for the presentation but that done i think anyway
Was the presentation how they failed to fit the need? LOL
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@scottalanmiller this was for the presentation -Each group will be required to deliver a presentation of about 30 minutes to the whole class, showing what they have installed including the major system components and salient features. The presentation should also include a critical evaluation of the applicability of the solution to the problems faced by the computing industry.
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@kelsey said in Virtualization and HA, Scalability:
@dustinb3403 thats the question problems faced by organisations implementing highly available and scalable computing resources, evaluation of potential solutions, selection of a solution for the organisation chosen and discussion and critical evaluation of implementations with particular reference to the lab systems installed.
One of the best ways to tackle this is to present unique scenarios and argue for implementations.
This isn't the kind of thing that can be chosen generically. The workloads, budget, value, performance, scale - all matter, a lot. Some workloads, like Active Directory or databases, would require that the features than most would promote be disabled.
Hopefully the class is tackling the idea of high availability in layers - HA at this layer would ignore application failure, for example.
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@kelsey our latest blog post might be useful for your class as well:
https://mangolassi.it/topic/16198/4-it-pitfalls-to-avoid-in-2018
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@scale thanks
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@kelsey said in Virtualization and HA, Scalability:
@scottalanmiller this was for the presentation -Each group will be required to deliver a presentation of about 30 minutes to the whole class, showing what they have installed including the major system components and salient features. The presentation should also include a critical evaluation of the applicability of the solution to the problems faced by the computing industry.
Yeah, there's no general HA concept. It all depends on what needs to be HA.
What typically needs to be HA is a service being provided, whether it's a website or web application, database, cloud computing infrastructure, storage, etc... you can have hardware HA, but not application HA, vice versa, or both. There are a lot of factors.
Are you supposed to pick out a specific application or platform that needs HA, and present a solution?
For example, MS SQL server can be HA simply (from a high level) by using two different servers and the the built-in software HA features. And that's if you are even using MS SQL.
If you need a single HA hypervisor, depending on your hypervisor, your solution will be different... though you'll still need more than one physical server. If you use internal storage vs external storage, multiple redundant SANs... the rabbit hole is so deep and HA depends on so many factors.
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@tim_g
thats what we have to do but the part i am on is the report which is this - In addition to the practical task, an individual report is to be produced on the application of virtualisation technologies to an organisation of your choice. The report should contain an introduction to the problems faced by organisations implementing highly available and scalable computing resources, evaluation of potential solutions, selection of a solution for the organisation chosen and discussion and critical evaluation of implementations with particular reference to the lab systems installed. -
@kelsey said in Virtualization and HA, Scalability:
This is a picture of an IPOD. . .
AKA Inverted Pyramid of Doom.
If you lose your storage server for any reason, both physical host 1 and 2 are useless.
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@dustinb3403 thanks
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@kelsey Do you know why if you lose the storage server the physical hosts 1 and 2 are useless?
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@dustinb3403 not really
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@kelsey so the report is based on NOT having HA? Then you have a HUGE opportunity to teach the class why the challenge is that even the professor failed to identify that this isn't HA!
In fact, this is what we call an LA (Low Availability) solution. We have SO much reference material on this for you.
https://mangolassi.it/topic/8822/why-dual-controllers-is-not-a-risk-mitigation-strategy-alone
https://mangolassi.it/topic/8743/risk-single-server-versus-the-smallest-inverted-pyramid-design -
@kelsey said in Virtualization and HA, Scalability:
@dustinb3403 not really
Because you have this huge network with all of these pieces, but all of them depend on the most fragile piece - the storage server. The storage piece, often a SAN or NAS device, is the most likely piece to fail out of all of them, and it is a piece that is completely unnecessary, and it is the one piece that is not protected in any way.
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@kelsey said in Virtualization and HA, Scalability:
@dustinb3403 not really
Look at the image and the triangle I drew on it.
Based on the image, we have to assume that all Virtual Machine storage is on the "storage server". The Physical server 1 and 2 are running the hypervisor, and attaching to the storage server (iscsi or DAS or some other method).
In this case though the method doesn't matter.
If that storage server goes down, your VM files are inaccessible and the hypervisors cannot load and run them.
IE you're up shits creek without a paddle until the storage server is repaired.
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What your professor is proposing is know as the most standard scam in the IT industry - every vendor who thinks that they can trick someone because they don't understand risk uses this model as it is the most effective way to empty the pockets of those that try to "buy" their IT rather than doing their IT themselves.
It creates a dependency chain, for no reason, and every layer completely depends on all other layers, with the most dangerous layer having no protection at all.
http://www.smbitjournal.com/2014/11/the-weakest-link-how-chained-dependencies-impact-system-risk/
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@dustinb3403 i get it now thanks
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@kelsey said in Virtualization and HA, Scalability:
@dustinb3403 i get it now thanks
This also means, if the switch that the storage server goes down, you're in the same boat.
Which this leads into the conversation that @scottalanmiller just brought up which is dependency chain.
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@dustinb3403 said in Virtualization and HA, Scalability:
@kelsey said in Virtualization and HA, Scalability:
@dustinb3403 not really
Look at the image and the triangle I drew on it.
Based on the image, we have to assume that all Virtual Machine storage is on the "storage server". The Physical server 1 and 2 are running the hypervisor, and attaching to the storage server (iscsi or DAS or some other method).
In this case though the method doesn't matter.
If that storage server goes down, your VM files are inaccessible and the hypervisors cannot load and run them.
IE you're up shits creek without a paddle until the storage server is repaired.
Right, in this example, if the storage server fails, EVERYTHING fails.
Also, if the switch fails, EVERYTHING fails.
Also, if both hypervisors fail at the same time, EVERYTHING fails.So there are three layers of potential failure. Two of them have no protection at all. Not only do they have no protection, they serve no purpose. Why is there a switch here? No idea, it's totally unnecessary. Why is there a storage server here? No idea, it is totally unnecessary. Those would never exist unless a sales person thought that they could scam the customer and really took a risk at not getting caught. (But we see this EVERY day. It's awful.)
Simply by removing those points of risk (there is no reason to replace them) we can take 99.99% of the risk out of the system.
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@kelsey said in Virtualization and HA, Scalability:
@dustinb3403 i get it now thanks
But does your professor?
