Azure Questions & Answers - 1

1. Name the "kernel" of the Azure Cloud operating system

Fabric Controller (FC). It provisions, stores, delivers, monitors and commands the virtual machines (VMs) and physical servers that make up Azure.

2. Critical business applications require a low RTO & RPO. True or False

True

3. Scaling-out is a preferable scaling method for cloud applications than scaling-up - True or False

True. Scaling up is constrained by what VM sizes are available

4. Azure organizes VM sizes into different machine series. What are they & what is specialty of each series?

• A series - generic workloads
• A8-A11 - high performance computing
• D series - high CPU & high temporary data IO
• DS series - high I/O workloads
• G series - high CPU & high memory demands

5. When you create a VM in Windows Azure you are provided with a temporary storage automatically. What is the location of this storage

This temporary storage is “D:” on a Windows VM and it is “/dev/sdb1” on a Linux VM.

6. What is the purpose of temporary storage in VMs?

This temporary storage is used to save the system paging file.

You can also use this drive only to store temporary data, which you can afford to lose at any time.

Like for example: If your workflow involves getting content from the blob, processing it and storing it back to the blob then you could download content to the temporary storage, process the content, then take the processed content and save it back to the blob.

7. When will the data on temporary drive in a VM be lost?

When you resize the VM, when you shutdown or restart your VM, when your VM is moved to a different host server(due to service healing, shutdown and restart), when the host is updated, when the host experiences a hardware failure etc.

8. Is there any cost associated with temporary storage?

The temporary storage provided with each VM has no extra cost associated with it for storage space as well as for transactions.

9. How are VHDs in Azure Storage charged?

VHD's are persisted as page blobs and so you are charged for the space consumed in the blob. 

For Windows Azure Drive storage, you will be billed only for the storage space used by the page blob and the read/write transactions to the page blob. You will not be charged for read transactions that utilize the local drive cache. Windows Azure Drive usage is billed at the same rates as standard Windows Azure Storage and is included with Windows Azure Storage usage in your bill. - Official Azure documentation

10. If I place VMs in different cloud services in Azure, can they still talk to each other?

Yes. All VMs within the cloud service can communicate with each other via the DIP. VMs in different cloud services can communicate via endpoints defined on the cloud service VIP. Although this is fine for limited communications, it isn't efficient.

The better solution is to place the cloud services in a virtual network, which then allows all the VMs in cloud services on the same virtual network to communicate directly using the internal (DIP) addresses

Note - Features of Azure services may change at any time.