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Preparing for E20-555

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Hi All,

I have completed my ISMv2 certification some month ago and currently I'm preparing for the technical architect for Isilon Solutions. As learning resources I'm using the Video ILT, but after taking a practice test for this certification I mentioned, that I need to now a lot of formulas to calculate the customers requirements.

Those ones were not mentioned in the Video ILT course.

Are there any additional resources, where I can look up the information I need to pass the exam?

I know that Cisco has books for their certifications. Has EMC such a book, guide or formulary for Isilon?

Do you have more advices for exam preparation?

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Re: Preparing for E20-555

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Hello Alex,

I'm not completely clear on your question.  There are no standalone formulas per se, we generally direct people to the Isilon sizing tool for all sizing exercises.

The sample question you have above is different, it is more of a straignt capacity calculation.  Here's an example of how I would go about finding the answer.

There really isn't sufficient information to get overly wrapped around the axles on this so we'll go with over simple calculations.  (200 TB * 30% growth per year * 7 years of data) = gross amount of data - (((((((200 * 1.3) *1.3) *1.3) * 1.3) * 1.3) * 1.3) * 1.3) gives you the gross amount of storage, in this case ~1,255 TB.  Now you'll have to figure out how may X series nodes it would take to accommodate that amount of data at a maximum of 75% utilization - 1,255 / .75 or roughly 1,674 TB of space needed.  Becasue we don't know the size of the files involved, we have to make assumptions that they will be stripped across all nodes.  Based on the number of nodes you come up with, how much overhead will you need to accommodate N+3 protection?  Basically for this exercise that we don't have enough information to do a accurate calculation, so we have to assume 3 additional nodes to accommodate the protection overhead.

Does that help at all?  Please let me know.

Barry Ballard

barry.ballard@emc.com

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Re: Preparing for E20-555

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First off, congratulations on passing the ISM!

For the E20-555, the best place to start is the exam description here: https://education.emc.com/content/_common/docs/exam_descriptions/e20-555_TA_Isilon_Solutions_And_Des...

At the end of the description it lists the recommended training, which in this case includes 1 e-Learning and 2 VILTs:

You don't mention which VILT you are using; it's possible that you might need to take more than one.

The Practice Test is also a good place to go, so you're on the right path there.

Another option is to ask specific questions here. If you're looking at a problem, either in the VILT or the Practice Test, you can post the question here, along with the work you've done to solve it, and an SME can take a look at it and help you out. There are plenty of past questions in this forum too, so you can search for other questions related to this exam.

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Re: Preparing for E20-555

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Hi Kate,

thank you for your quick reply!

I'm using the recommended training from the exam description. Also I have done the e-Learning course and the Isilon Infrastructure Solutions VILT. Currently I'm at Module 3 of the Design VILT.

But there are no hints to formulas I need in the exam to size the customers requirements.

I have found a sample question:

The customer want to implement a X-Series cluster. They have 200 customers and they grow 30% per year. They have 200TB of storage utilized and they keep the patient data for 7 years. The customer want to use N+3 protection and the data shouldn't exceed 75% utilization.

I have to figure out, what the recommended minimal initial configuration is.

X200 or X400 nodes, size of the HDDs and the count of nodes needed.

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Re: Preparing for E20-555

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Hello Alex,

I'm not completely clear on your question.  There are no standalone formulas per se, we generally direct people to the Isilon sizing tool for all sizing exercises.

The sample question you have above is different, it is more of a straignt capacity calculation.  Here's an example of how I would go about finding the answer.

There really isn't sufficient information to get overly wrapped around the axles on this so we'll go with over simple calculations.  (200 TB * 30% growth per year * 7 years of data) = gross amount of data - (((((((200 * 1.3) *1.3) *1.3) * 1.3) * 1.3) * 1.3) * 1.3) gives you the gross amount of storage, in this case ~1,255 TB.  Now you'll have to figure out how may X series nodes it would take to accommodate that amount of data at a maximum of 75% utilization - 1,255 / .75 or roughly 1,674 TB of space needed.  Becasue we don't know the size of the files involved, we have to make assumptions that they will be stripped across all nodes.  Based on the number of nodes you come up with, how much overhead will you need to accommodate N+3 protection?  Basically for this exercise that we don't have enough information to do a accurate calculation, so we have to assume 3 additional nodes to accommodate the protection overhead.

Does that help at all?  Please let me know.

Barry Ballard

barry.ballard@emc.com

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