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i don't have enough knowledge about storage systems but have to tell my audiences about how storage works in organization data centers.

For this purpose to keep things simple, first i want to show them a layer from top to bottom and then i want to explore all these layers.

What i mean by layered model in storage architecture?

i want to start my presentation something like that, first layer can be applications, application request a data from storage and then ... ... (the topics i want to cover are file sytems, metadata,the physical implementation of storage (das, nas etc.) ... the request comes to the storage device and storage device (depends on the technology) goes through the disk and disk send back the data using iscsi protol, we can say that the iscsi protocol managing the path between... ...

if you help me explain these steps layer by layer by examples and names of some key technologies to be defined, really appreciate it.

thanks.

Berkay
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2 Answers2

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You're in luck, because there's a GREAT blog called SysAdmin1138 Expounds that just covered this.

The series of posts is called "Know your I/O".

Intro

The Components

The Technology

Caching

I really recommend you check them out. I'm certain that it'll help you and your audience.

Matt Simmons
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  • okey thanks, it seems great.I will read all these and analyze for my presentation. – Berkay Apr 05 '10 at 19:59
  • Any examples that i can give, for example when we explain tcp/ip we are just giving the highway, trucks etc. – Berkay Apr 05 '10 at 20:28
  • Depending on the level of experience you're working with, the old post-office analogy can go far. What part of TCP/IP are you explaining, and to who? – Matt Simmons Apr 05 '10 at 20:31
  • I have some 'real world examples' going up tomorrow, which may help with some of this. I don't cover Speaking To Managers, though. I probably should. An analogy that could work would be a (reliable) bucket-brigade with hand signals for whether the bucket got where it was going. Just a thought. – sysadmin1138 Apr 05 '10 at 20:43
  • The post office example is a good when explaining the TCP/IP. i'm just looking for such an example to explain storage architecture. – Berkay Apr 05 '10 at 20:53
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Matt already pointed to it, but the link titled "The Components" shows the full stack from bottom (disk drive) to top (file-based application) in more detail than you probably care about. It's all about the abstraction. The article on Caching goes into some detail about when writes are reported as committed to applications, since that can vary due to a number of reasons. The article on Technology goes into some details about SATA vs SAS drives, which I found interesting to write.

What I didn't go into much detail on are filesystem specific details such as metadata handling, journaling, or large-directory handling. That depends on each filesystem individually, and undergoes constant change (in the linux world anyway). Generally speaking, journaled filesystems write metadata to the journal first, and then commit actual data; which means that slowdowns in metadata processing can slow down writes even if your storage I/O channels are clean. For an example of how this can work on NTFS, I go into it here.

sysadmin1138
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