MongoDB. Homework 6.

Всем привет, долго я тут не писал, особо не было времени, да и ждал, пока закончатся on-line курсы MongoDB, так как негоже выкладывать ответы до того, как придут результаты)

Homework: Homework 6.1

Which of the following statements are true about MongoDB replication. Check all that apply.

The minimum sensible number of voting nodes to a replica set is three.MongoDB replication is synchronous.The Mongo shell is capable of attaching to a replica set and automatically failing over.By default, using the new MongoClient connection class, w=1 and j=1.The oplog utilizes a capped collection.

Homework: Homework 6.2

Let's suppose you have a five member replica set and want to assure that writes are committed to the journal and are acknowledged by at least 3 nodes before you proceed forward. What would be the appropriate settings for w and j?

Let's suppose you have a five member replica set and want to assure that writes are committed to the journal and are acknowledged by at least 3 nodes before you proceed forward. What would be the appropriate settings for w and j?
w="majority", j=1 был правильным

Homework: Homework 6.3

Which of the following statements are true about choosing and using a shard key:

The shard key must be uniqueThere must be a index on the collection that starts with the shard key.Mongo can not enforce unique indexes on a sharded collection other than the shard key itself.Any update that does not contain the shard key will be sent to all shards.You can change the shard key on a collection if you desire.

Homework: Homework 6.4

You have a sharded system with three shards and have sharded the collections "grades" in the "test" database across those shards. The output of sh.status() when connected to mongos looks like this:

Which shards would be involved in answering the query?

s0,s1 and s2s0s1s2

Homework: Homework 6.5

In this homework you will build a small replica set on your own computer. We will check that it works with validate.py, which you should download from the Download Handout link. 

kjvjkl3290mf0m20f2kjjv - правильный ответ