Exam 5V0-21.20 topic 1 question 12 discussion

Actual exam question from VMware's 5V0-21.20

Question #: 12
Topic #: 1

An architect has been asked to plan the impact of a storage policy change to one of the production All-Flash based vSAN datastores. The change will reduce the failures to tolerate value from 2 to 1 for objects with a RAID-1 (Mirroring) layout in the existing policy. This change will be applied to multiple VMs.
Which statement is correct in this scenario?

A. FTT-2 requires another change to apply a RAID-6 configuration.
B. The policy will need to be recreated and applied with an additional tag.
C. There will be no objects rebuilt that impact performance.
D. There will be an object rebuild impact on performance.

Show Suggested Answer

Suggested Answer: D 🗳️

by Rabbit117 at March 13, 2021, 5:07 p.m.

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Rabbit117

Highly Voted 4 years, 3 months ago

I think C is correct. I have tested changing FTT from 1 to 0 and there was no component rebuild, I assume it's the same when going from 2 to 1.

upvoted 7 times

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Lazylinux

Most Recent 3 years, 6 months ago

D for me remember going from FT2 to 1 meaning you losing 2 hosts from the cluster based on 2n+1 and hence reconfig of the storage policy ..here vmware comments Because the managed storage policy varies based on cluster size, adding or removing hosts will trigger a storage policy reconfiguration if it changes the size of the cluster so that it requires a different policy. For example, if you add an additional host to a cluster containing five hosts, the storage policy for that cluster is reconfigured from using 1 failure - RAID-1 (Mirroring) to 2 failures - RAID-6 (Erasure Coding). The reverse happens if the extra host is removed and the number of hosts is reduced from six to five. https://docs.vmware.com/en/VMware-Cloud-on-AWS/services/com.vmware.vsphere.vmc-aws-manage-data-center-vms.doc/GUID-EDBB551B-51B0-421B-9C44-6ECB66ED660B.html

upvoted 1 times

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DSITTA

3 years, 8 months ago

C is correct. D should be right if you have RAID5/6 that need a complete redistribution of coded parity; alse need some additional space because of old copies are not removed until syncing new copies. With RAID 1, only witness and second copy are deleted. Non rebuild

upvoted 1 times

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wpjoulekkading

4 years ago

C would be my pick. Changing a FTT from 2 to 1 would simply remove/delete additional disk components from disk to comply with the storage policy. there will be no rebuild/resync of data, only when you change the policy from FTT 1 to 2 there will be a performance impact.

upvoted 3 times

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vJoeyB

4 years, 1 month ago

C is correct

upvoted 2 times

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dbus81

4 years, 3 months ago

D is correct

upvoted 4 times

HappyPower

4 years ago

D is correct, I try it in my lab

upvoted 2 times

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