Which procedure for backing up a relational database on EC2 that is using a set of RAlDed EBS volumes for
storage minimizes the time during which the database cannot be written to and results in a consistent backup?
A.
1. Detach EBS volumes, 2. Start EBS snapshot of volumes, 3. Re-attach EBS volumes
B.
1. Stop the EC2 Instance. 2. Snapshot the EBS volumes
C.
1. Suspend disk I/O, 2. Create an image of the EC2 Instance, 3. Resume disk I/O
D.
1. Suspend disk I/O, 2. Start EBS snapshot of volumes, 3. Resume disk I/O
E.
1. Suspend disk I/O, 2. Start EBS snapshot of volumes, 3. Wait for snapshots to complete, 4. Resume disk
I/O
Explanation:
https://aws.amazon.com/cn/premiumsupport/knowledge-center/snapshot-ebs-raid-array/ To create an
“application-consistent” snapshot of your RAID array, stop applications from writing to the RAID array, and flush
all caches to disk. Then ensure that the associated EC2 instance is no longer writing to the RAID array by
taking steps such as freezing the file system, unmounting the RAID array, or *shutting down the associated
EC2 instance*. After completing the steps to halt all I/O, take a snapshot of each EBS volume. http://
docs.aws.amazon.com/AWSEC2/latest/UserGuide/ebs-detaching-volume.html You can detach an Amazon
EBS volume from an instance explicitly or by terminating the instance. However, if the instance is running, you
must first unmount the volume from the instance.”
D is a correct ans.
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Both B & D are correct answers.
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D
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E
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Yes the answer is E , because if you start the EBS Snapshots and then resume Disk I/O , since this is a RAID configuration , you are risking the integrity of data that gets stripped across the RAID Volumes.
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recommendations from a-cloud-guru are to: stop instances
thus I vote for: B
br!
Carl
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Problem with B is that it doesn’t say to restart the instance
I pick E since you will have a consistent snapshot and a running instance when you are done.
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I agree with B
https://aws.amazon.com/cn/premiumsupport/knowledge-center/snapshot-ebs-raid-array/?nc1=h_ls
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In order to make a consistent SQL backup, the instance needs to be quiesced or stopped. Simply stopping writes for a moment isn’t going to put the DB into a good state for restores.
Since there is no way in AWS to quiesce a VM before snapshotting, your only option is to shut it down.
Correct answer can only be B as it is the only one that allows the DB to be consistent before the snapshot.
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E.
Suspend disk I/O, 2. Start EBS snapshot of volumes, 3. Wait for snapshots to complete, 4. Resume disk I/O
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