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Hi, Just wondering if anyone is familiar with Direct Attached Storage?

Ali

Any storage device (hard disk, floppy disk, optical disc, flash disk) connected directly to the computer instead of over a network is direct attached storage. Aren't you already familiar with these devices?

We aren't talking about things like "direct-attach cables", are we?

tsdnz wrote:Hi, Just wondering if anyone is familiar with Direct Attached Storage?

Ali

Perhaps you could expand upon what you mean by "Direct Attached Storage". As far as I am concerned that just refers, as Octocontrabass says, to a disk drive attached directly to a computer. Are you thinking of USB drives?

Oops, a bit vague.

SAN's and the protocols.

Ali.

Direct-attached storage is quite literally the opposite of a SAN.

Kazinsal wrote:Direct-attached storage is quite literally the opposite of a SAN.

Ok. Do you know SAN? What commands? Connected via PCIe?

Ali

This explains enough for me to start with. Now to contact the supplier and see what they have.

http://searchstorage.techtarget.com/def ... us-adapter

Ali

I don't think you should be buying things if you don't know what they do, but eh, it's your money.

NAS4Free can be set up to act as an iSCSI SAN. I'd be inclined to experiment with an old machine running this rather than buying new equipment.

iansjack wrote:NAS4Free can be set up to act as an iSCSI SAN. I'd be inclined to experiment with an old machine running this rather than buying new equipment.

Cheers, totally agree, purchasing old gear to test.

Edit: NAS4Free is not suitable for this project, many thanks.

Kazinsal wrote:I don't think you should be buying things if you don't know what they do, but eh, it's your money.

Need to learn this so spending some money is part of the process.

I am looking into the current storage technologies.
Do I use NAS (No, for this project it is not suitable)
Do I use SAN?
Do I use servers with hard disks?

I am writing a cloud storage system for the Cloud OS
My hardware supplier thinks we should be using SAN's, giving that I am not up-to-speed with SAN's I thought I should investigate, spend a few dollars if necessary.
The project requirements are not just storage capacity, but also IOPS and bandwidth.

If I buy a SAN with 24 hard drives, what are the restrictions, assuming small rpm, like 5400 or 7200.
IOPS at 100 x 24 = 2400, this will easily fit.
3 Gbps x 24 = 72 Gbps, this will not fit with in a 8 Gbps port.
This means that I can only guarantee a smaller Gbps to the end user than is possible as the SAN connection is limiting.

Ali

Ali

Normally, you would use a SAN fiber channel to read the raw data, do the processing on your servers, and return the processed data (which is hopefully much smaller than your raw data) to the client.

However, in your case, if there is no "processing" to be done, then you might as well use NAS servers, as the difference may be negligible. Your bottleneck will be your network between your server and your client.

But I'm no expert in this area. Maybe someone else can weigh in.

SpyderTL wrote:Normally, you would use a SAN fiber channel to read the raw data, do the processing on your servers, and return the processed data (which is hopefully much smaller than your raw data) to the client.

However, in your case, if there is no "processing" to be done, then you might as well use NAS servers, as the difference may be negligible. Your bottleneck will be your network between your server and your client.

But I'm no expert in this area. Maybe someone else can weigh in.

Cheers mate, thank you for your time.

The backbone is 10 GB NIC, moving to 40GB later (cost $$), each server has 2 x 10 GB NIC, giving 20 GB NIC availability.
The Userspace code is currently processing 14 million packets per second. 83 Bytes / packet.

You are right, that is exactly what is going to happen. SAN fiber read raw, process and send smaller, well most of the time.

I think the bottle neck is going to be the SAN fiber as it is 1/2/4/8/16/32 GB.
This means I can only get so many drives in the SAN array before the fiber is saturated, assuming full load, which is what I must guarantee to the users.
So I might just use the server hard drive bays and put in 6, which 6 x 3 GB is less than 20 GB.
It also means I can add more NIC's to the server for higher capacity.
I am about to ring the hardware guys and discuss option, before I get down to coding.
Note: For this server OS it will be using my [other] OS, which is processing around 20 million packets per second.

I am just going over the cost vs IOPS vs capacity and scalability.

Many thanks. Ali

I have talked with the hardware guys.

For performance, customization and pricing the best option is a server with a custom OS.

Now to sit down and create it.

Ali