Questions[cloud-storage](server)

Is there a cloud storage provider that provides file handles similarly to CIFS/SMB? We are using Dropbox and we would like to receive a warning when a file is opened by someone else (if there's a conflict it just creates a backup file). We don't like the solution where you manually lock files/folders with an interaction menu that Dropbox Business allows us to do. On the other side, we really enjoy the performance improvement from local caching with Dropbox!

We used to use a NAS via SMB in our local network, which supported this. But with a migration to remote work, this is no longer an option as the bandwidth of our office is not sufficient.

I am getting the below error in my Azure website and am scrambling to fix it:

Timeout expired.  The timeout period elapsed prior to obtaining a connection from the pool.  This may have occurred because all pooled connections were in use and max pool size was reached.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. 

Exception Details: System.InvalidOperationException: Timeout expired.  The timeout period elapsed prior to obtaining a connection from the pool.  This may have occurred because all pooled connections were in use and max pool size was reached.

How can I reset the pool or increase it?

So I'm just going to jump right in to the maths; My web host offers a server with 5x2TB drives, unmetered 1GB/s connection and can provision servers in 5 different data-centers, for ~$200/month.

If I got 3 of these servers and install OpenStack Swift on them, I have ~10TB (I know it'll be less than that but to keep the maths simple I'll just say 10TB) of storage with the same features as Rackspace Cloud but for $0.058/GB (Compared to $0.15/GB for Rackspace). Plus free, unlimited bandwidth. The servers could be provisioned in 3 different DCs for redundancy and for scaling new servers are active within an hour so we could scale up our storage reasonably quickly if we needed to. We'd also be using a CDN to deliver content, so yes there would be bandwidth charges but they would be external so irrelevant to the question.

Obviously it's only more effective if working with large amounts of storage (For, say 2GB it's a lot less efficient) but we have 7.5TB of backups on a RSC files account so our effective price per GB would be $0.078 (But that would decrease) compared to over $1000/month with our current Rackspace system.

So my question is, other than having to manage our own servers and putting a bit more effort into scaling, what's the difference between a self-managed storage system and something like Rackspace cloud, is it worth $/GB difference+bandwidth charges?

Some confusion because of my question so to make it simple :

"What kind of storage do big cloud providers use and why?"

As far as i understand, however I am not able to find any kind of official Storage networking differences between typical data centers and clouds, all cloud providers are using DAS different from the typical data centers.

Even DAS has many disadvantages than SAN or NAS, i want to learn the details why clouds using DAS either for storage or application purposes.

Any resource or description will be appreciated to make me clear.

EDIT: While reading the paper "Networking Challenges and Resultant Approaches for Large Scale Cloud Construction,David Bernstein and Erik Ludvigson (Cisco)" they mention that,

Curiously we do not see Clouds from the major providers using NAS or SAN. The typical Cloud architecture uses DAS, which is not typical of Datacenter storages approaches.

But here there is a conflict: in my opinion and also stated later in the paper, Clouds should use SAN or NAS because of DAS is not appropriate when a VM moves to another server yet still needs to access storage from original server.

What are other reasons effects clouds to prefer DAS, NAS or SAN? what kind of storage do big cloud providers use and why?

I am thinking of using a cloud service to backup one of my client's website.

My (clients) main concerns are (in decreasing order of importance)

1. Protection of IP (trade secrets, source code), user account details etc
2. Uptime guarantee offered by service provider (to minimise webserver down times)
3. Cost
4. Upload/download speeds

Ideally, I would like service that does not have a long tie in (i.e. I would prefer a kind of "pay-as-you-go" service)

I would also like to avoid vendor lockin, where it is next to impossible to move to another service.

I would like some general guidelines on:

1. How to go about choosing a service provider
2. Who are the main players in the field
3. recommendation of software to use for: backup/restore/ and upload/download of the saved/restored files

The server software is either going to be Ubuntu or Debian (I'll probably post a question on which OS to go for as a server - I am already familiar with Ubuntu)