1
Q
What are blobs?
A
files for the cloud
2
Q
What’s virtual directories?
A
to give a blob hierachical names that looks like file path eg. finance/bidgets/2017/q1.xls. Let u navigate.
3
Q
What does unstructured data mean?
A
data that doesn’t adhere/attached to a particular data model/definition (eg. text, binary data)
4
Q
What does Blob Storage store?
A
store massive amounts of unstructured data.
5
Q
What are the two performance levels of storage account Azure Storage offers?
A
- Standard: This is the standard general-purpose v2 account and is recommended for most scenarios using Azure Storage. Support Blob, File, Queue, Table Storage.
- Premium: Premium accounts offer higher performance by using solid-state drives. If you create a premium account you can choose between three account types, block blobs, page blobs, or file shares.
6
Q
What are the different access tiers for block blob data?
A
- Hot: optimized for frequent access of objects in the storage account. Highest storage costs, but the lowest access costs. Default
- Cool: optimized for storing large amounts of data that is infrequently accessed and stored for at least 30 days. Lower storage costs and higher access costs compared to the Hot tier.
- Archived: available only for individual block blobs. Optimized for data that can tolerate several hours of retrieval latency and will remain in the Archive tier for at least 180 days
7
Q
Which access tier is the most cost-effective option for storing data?
A
Archived access tier
8
Q
Which access tier is the most expensive option for accessing data?
A
Archived access tier
9
Q
Which access tier has the highest storage cost?
A
Hot tier
10
Q
Which access tier has the lowest access cost?
A
Hot tier
11
Q
What are the different blob types?
A
- Page blobs
- Append blobs
- Block blocs
12
Q
What is Page blobs used for?
A
- store random access files up to 8TB
- store virtual hard drive (VHD) files
used by Azure VM (filename.vhd) - random read/write scenarios
13
Q
What is Append blobs used for?
A
- made up of blocks like Block blobs, but are optimised for append operations
- ideal for logging data from virtual machines.
14
Q
What is Block blobs used for?
A
- store text and binary data, pictures, video etc
- best choice for most scenarious that doesn’t specifically call for append/page blobs
15
Q
What are the ways to rehydrate blob from achive tier?
A
- Copy an archived blob to an online tier
(cool/hot tier) - Change a blob’s access tier to an online tier (cool/hot tier)
16
Q
What’s Azure Cosmos DB?
A
NoSQL db,
provides low latency, elastic scalability of throughput, high availability
17
Q
Benefit with Azure Cosmos DB?
A
perform near real-time reads and writes against all the regions you chose for your database
18
Q
What are the different consistency levels in Cosmos DB?
A
- Strong consistency
- Bounded staleness consistency
- Session consistency
- Consistent prefix consistency
- Eventual consistency
19
Q
What’s strong consistency?
A
- client always sees latest committed write. Never see uncommited or partial write.
- serving requests concurrently (at the same time)
lowest availability, highest latency, lowest throughput
20
Q
What’s eventual consistency?
A
- Weakest form of consistency
- No ordering guarantee for reads. Client might read values older than the ones it read before.
- no guarantee getting write back when read.
Highest availability, lowest latency, higher throughput, lowest cost
Eg. Retweets, Likes, nonthreaded comments
21
Q
What can Cosmos DB item represent as?
A
Depending on which API you use, an Azure Cosmos DB item can represent either a document in a collection, a row in a table, or a node or edge in a graph.
22
Q
When creating a container in Cosmos DB, where can you configure throughput ?
A
- Shared provisioned throughput mode
- Dedicated provisioned throughput mode
23
Q
What’s Dedicated provisioned throughput mode?
A
The throughput provisioned on a container is exclusively reserved for that container and it’s backed by the SLAs.
24
Q
What’s Shared provisioned throughput mode?
A
share the provisioned throughput with the other containers in the same database (excluding containers that have been configured with dedicated provisioned throughput)
25
What's request units (RUs)?
the cost of all database operations are express by request units (RUs)
26
What are the 3 modes to create Azure Cosmos DB?
1. Provisioned throughput mode
2. Serverless mode
3. Autoscale mode
27
What's Provisioned throughput mode for Cosmos DB?
provision number of RUs for ur app on a per-second basis in increments of 100 RUs.
28
What's Serverless mode for Cosmos DB?
at the end of billing period, get billed for the number of consumed RUs
29
What's Autoscale mode for Cosmos DB?
Automatically and instantly scale the throughput (RU/s) of your database or container based on its usage.
Suited for mission-critical workloads with unpredictable traffic patterns. Require SLAs on high performance and scale
30
What's a lifecycle management policy?
a collection of rules in a JSON document.
Each rule definition within a policy includes a filter set and an action set. The filter set limits rule actions to a certain set of objects within a container or objects names. The action set applies the tier or delete actions to the filtered set of objects
31
How many rules are required in a policy, and max?
At least one rule is required in a policy. You can define up to 100 rules in a policy.
32
What are the parameters a rule within the policy has?
1. name (String); rule name can include up to 256 alphanumeric characters. Rule name is case-sensitive. It must be unique within a policy. Required
2. enabled (Boolean); An optional boolean to allow a rule to be temporarily disabled. Default value is true if it's not set.
3. type (Enum); The current valid type is Lifecycle. Required
4. definition (object that defines the lifecycle rule); Each definition is made up of a filter set and an action set. Required
33
What does rule filter limit?
Filters limit rule action to a subset of blobs within the storage account.
If more than one filter is defined, a logical AND runs on all filters.
34
What does filters include?
1. blobTypes; an array of predefined enum values. Required
2. prefixMatch; an array of strings for prefixes to be match. Each rule can define up to 10 prefixes. A prefix string must start w/ a container name eg. "container1/foo". Not required
3. blobIndexMatch; an array of dictionary values consisting of blob index tag key and value conditions to be matched. Each rule can define up to 10 index tag condition. Not requires.
35
What are the rule actions you can apply in a Blob storage lifecycle?
1. tierToCool; support blockBlob, snapshot and version
2. enableAutoTierToHotFromCool; support only blockBlob
3. tierToArchive; support blockBlob, snapshot and version
4. delete; support blockBlob, appendBlob, snapshot and version
36
What happens if you define more than one action on the same blob?
lifecycle management applies the least expensive action to the blob.
Action delete is cheaper than action tierToArchive. Action tierToArchive is cheaper than action tierToCool.
**delete < tierToArchive < tierToCool**
37
What can you use the Microsoft .NET SDK v3 for?
1. Create CosmosCLient
2. Create a database (CRUD operations)
3. Create a container (CRUD operations)
4. Create an item (CRUD operations)
38
What are the only two HTTP properties available for containers in Azure Blob Storage?
1. ETag; an identifier for a specific version of a resource. It lets caches be more efficient and save bandwidth, as a web server does not need to resend a full response if the content was not changed
2. Last-Modified
39
What HTTP properties are "only" available for blobs?
1. Last-Modified
2. Cache-Control
3. Origin
4. Range
40
What's the first step required to retrieve a reference to a Redis db by using the GetDatabase method?
Create a ConnectionMultiplexer object.
41
What are the different types of Shared access signature (SAS)?
1. User delegation SAS; secured w/Azure Active Directory credentials applies to Blob storage only.
2. Service SAS; secured w/storage account key, access to Blob storage, Queue storage, Table storage or Azure files. Support a single service.
4. Account SAS; secured w/storage account key, access to resources in one or more of the storage services.
NB. All of the operations available via a service or user delegation SAS are also available via an Account SAS.
42
Blob containers support system properties and user-defined metadata. What are they?
System properties; exist on each Blob storage resource. Some of them can be read or set, while others are read-only. Some system properties correspond to certain standard HTTP headers. The Azure Storage client library for .NET maintains these properties for you.
User-defined metadata; consists of one or more name-value pairs that you specify for a Blob storage resource. You can use metadata to store additional values w/the resource. Metadata values are for your own purpose only, and don't affect how the resource behave.
43
When you rehydrate a blob stored in the Archive tier, which destination should you use?
Rehydrate it to online tiers (Cool or Hot). The destination can be any storage account in the same region.
44
What's bounded staleness consistency?
reads are guaranteed to honor the consistent-prefix guarantee.
The reads might lag behind writes at most "K" version (updates) of an item, or by "T" time interval, whichever reached first.
The staleness can be configured in two ways:
1. Number of versions K of the item
2. The time interval T reads might lag behind the writes
45
What are the minimal value of K and T for a single region and multi-region account?
Single region:
K = 10 write operations
T = 5 seconds
Multi-region:
K = 100 000 write operations
T = 300 seconds
46
What's session consistency?
within a single client session, reads are guaranteed with **consistent-prefix**, monotonic reads and writes, read-your-writes, and write-follows-reads.
47
what's monotonic reads and writes guaranteed?
monotonic read guaranteed = reads a particular value of a data item, it will not later read an earlier value for that item.
monotonic write guaranteed = This ensures that writes from a session are applied in a monotonically increasing order. Each write operation is never overridden or rolled back by a later write
48
What's consistent prefix consistency?
**Single document writes updates** works like in Eventual consistency.
**Batch updates** within a transaction are returned consistent to the transaction in which they were committed.
Write operations within a transaction of **multiple docs** are always visible together.
49
Where is Bounded Staleness beneficial?
To single-region write accounts with two or more regions.
Bounded Staleness provide the same write consistency guarantees as Session and Eventual Consistency, for a single-region account.
50
Which consistency level is the most widely used for both single region and globally distributed apps?
Session consistency, cause it provides write latencies, availability and read throughput comparable to that of Eventual consistency.
51
What are the supported Cosmos DB API's?
1. SQL (core API = if we don't have a reason to choose one of the other API's we should choose SQL)
2. Cassandra
3. MongoDB
4. Gremlin; graph database
5. Azure Table
52
Can Archive tier be set as default on Storage level or Blob level?
Archive storage can be set as a tier at the blob level but can't be set at default for a storage account.
53
What data access tier can be set as default for a storage account?
Hot (default) and Cool
54
What are the two Data Rehydration Priorities?
1. **Standard Priority**; takes a few minutes to up to 15 hours depending on other req, size of data.
2. **Hight Priority**; takes around an hour for objects that are less than 10 GB. Also depending on data size etc. Cost more than Standard Priority
55
What are the different Data Redundancy options?
1. Locally Redundant Storage (LRS)
2. Zone-redundant Storage (ZRS)
3. Geo-redundant storage (GRS)
4. Geo-zone-redundant Storage (GZRS)
5. Read-access Geo-redundant Storage (RA-GRS)
6. Read-access Geo-zone-redundant Storage (RA-GZRS)
56
What are the ways you can authorize requests to Blob Storage?
1. Shared Key (Storage Account Key); send in connection strings
2. Shared Access Signature (SAS)
3. Azure Active Directory
4. Anonymous public read access; at blob container level
