E20-324 VNX Certification

If you do not mind, can you please share calculation for this question please....

SAN Copy (ISC) on a clone of a 512GiB source LUN, host generates 500 4KiB IOPS with a R/W ratio of 3:1.

The Clone is fractured every 30 minutes.

Q: how much is crossing the link during this 30 minutes

swapnil, how are you currently calculating this? Can you explain how you're trying to solve this question?

Hi, swapnil!

As Kate suggested, post the method you're using to solve the question, and explain the steps you take. I'll have a look once you've done so, and will post some pointers.

what was the calclation for the first question how was 12.5MB/s attained all the responses to NOT explain this

Hello Kate do you have the calculation for these types of questions they are found Nowhere...?

Sam Jaloma

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Please provide the specific question you're having trouble with, and also explain how you are currently calculating the answer.

Here is another one

A customer wants to add Flash drives to their VNX array and use them as FAST Cache. They want at least 250 GiB of FAST Cache capacity on each SP. There are no Flash drives in the array and they want to follow EMC best practices on hot spares. The answer here is 7 200 GB disk or 331 is that right 3 x186 = 558 I do not get this answer why is this not 2 + 2 +1 5 by 200Gb disk...?

Here is another question I do not get...?

two VNX systems running MirrorView/S. Two LUNs on one system, 512 GiB each, are being replicated to the other system. The systems are connected with a 10 Mb/s line which has a 2:1 compression ratio. The primary LUNs have a constant workload of 400 IOPs in total, 100% random, 8 KiB in size, read/write ratio of 3:1.

Approximately how much user data needs to be synchronized if being out of sync for only two hours is acceptable?

Congrats for passing the Exam.

I am searching for the pdf materials to prepare for the vnx exam.

Can anyone help to share me the vnx pdf study materials to prepare for the exam.

I can also buy it for second price.

Please advise,

Thanks,

karthik

The training material for the E20-324 VNX Solutions Design Exam for Technology Architects is available here: https://education.emc.com/part/certification/framework/ta/vnx.aspx

Since this course is on the TA track, you will need to log in with your Partner account to view the details for this course.

Dear Kate,

Thank you for the link.

I don't have a partner account. am not a customer nor partner nor emc employee.

Can i create a partner account by myself  is it  paid ?

Please advise.

Thanks,

karthik

EMCISA, because you are not an Employee, Partner, or Customer, you will be unable to enroll for the VNX training.

We do offer a selection of open courses, like ISMv2 that are available to anyone. They are:

Data Scientist Track - Data Science and Big Data Analytics

Cloud Architect Track - Cloud Infrastructure and Services, Virtualized Infrastructure, ITaaS

Data Center Architect Track - Enterprise Storage Networking, Enterprise Backup Recovery

These tracks are listed on our Certification Framework page, at the top. They are listed under Audience as 'Open'.

Question:

Here is another question I do not get...?

two VNX systems running MirrorView/S. Two LUNs on one system, 512 GiB each, are being replicated to the other system. The systems are connected with a 10 Mb/s line which has a 2:1 compression ratio. The primary LUNs have a constant workload of 400 IOPs in total, 100% random, 8 KiB in size, read/write ratio of 3:1.

Approximately how much user data needs to be synchronized if being out of sync for only two hours is acceptable?

The mirrored LUNs are 512 GB in size, so have an extent size of 256 kB. The link is 10 Mb/s [1 MB/s when divided by 10 to get bytes from bits], and with a 2:1 compression ratio is equivalent to a 2 MB/s link. The 2 LUNs see a total of 100 writes/s with random 8 kB writes, which is 800 kB/s that needs to cross the link. Those writes occur even when synchronization is happening, and consume part of the link bandwidth. The remainder is 1.2 MB/s or so, and in 2 hours [7200 seconds] can carry a total of 1.2 x 7200 MB = 8640 MB of data. That's the amount that will need to be synchronized.

Note that you can also calculate, for example, how long the mirrors can be fractured: since each host write dirties an extent of 256 kB, and we can copy 8640 MB in the time allowed, that's 34,560 writes. Since we see 100 writes/s, that's a total of 345.6 seconds worth of writes. That means that the mirrors can only be fractured for 345 seconds, or around 5 3/4 minutes, in order to resynchronize within 2 hours.

Can you please explain what you mean by two 8/16?