LVM Idea

[SamK]

The draft documentation recommends the use of LVM to manage eBox storage. I was interested in creating visual representations of some ways in which LVM might be used in eBox machines.  The attached graphics are the results.

Three scenarios are covered each having a horizontal and vertical representation. I find they assist in visualizing the structure of the storage, and post them as other eBoxers might also find them helpful.  Might they be useful in the official eBox documentation?

[poundjd]

Sam,
     They LOOK WONDERFUL.  really helps to understand how the different levels, disks, partitions, volumes and whats mounted.  Thanks.
-jeff

[SamK]

...really helps to understand how the different levels, disks, partitions, volumes and whats mounted...

Thanks for your kind comments, they give encouragement.

Which representation do you find easiest to understand, horizontal or vertical?  Your feedback on this point will be most welcome; also from other eBoxers and devs.

[Javier Amor Garcia]

SamK those graphs are awesome!.
About your question I found the 'stack' model  more easier to undestand.

Thanks for your work

[sixstone]

I do agree with Javier. Awesome job and I'd prefer stack model .

Best,

[poundjd]

Sam,
  I would think that both models should stay, they complement each other.  That way a "Lateral" thinker can see a "Lateral" layout and a "Vertical" thinker can see the "Vertical" layout.
-jeff

[RoboJ1M]

Definitely the stack.
That looks fantastic, it's the only visualisation of HDD + RAID + LVM I've ever see that works.
I have an additional idea that I think help improve visualisation of which disk the partitions are located on (attached)
Bi-Directional stack!

So, who's going to write the perl script then? 

J1M.

[SamK]

Many thanks for the feedback.

In my view the 'stack'(horizontal) diagram is the easiest to understand.  This is probably due to its simplicity; it attempts to express the concept and does so by omitting much of the detail. My opinion is this is worth keeping.

By including additional details (including the relationship between the physical elements and logical components) the diagram rapidly becomes more complex.  The attached diagram is based on the most involved of the scenarios expressed in the earlier series. It attempts to describe the relationships/details in a slightly different way.

Again I invite feedback.

• Does it convey the meaning any more clearly than the previous (non-stack) version?
• Is it more helpful to newer eBox users?
• Is this best used in conjunction with the 'stack' diagram?
• Is it simply an interesting exercise but should now be discarded?

[RoboJ1M]

Hi,

I think I'm getting confused about which one is which. I prefer your type of diagram that I drew a version of.
Stack is a bit ambiguous, as both types of diagram involve stacked elements.
The type of diagram that I prefer and copied, I'm going to arbitrarily name 'Jenga' because it looks a bit like a top down rainbow game of Jenga.

So, in answer to your questions:

1) Yes, it does convey meaning more clearly than the previous versions. The horizontal logical volumes are a big improvement, much more info displayed. I also like how it's clear where the partitions reside (sda1 on sda, etc.)
2) I don't know. I'll ask someone here who's not a linux user.
3) I think Jenga is superior to Stack, Stack can't store which partitions are where, not enough dimensions.
4) No, I don't think so. I still say Jenga is the best way I've ever seen for representing disk layouts.

One criticism, the HDD (grey) layout. One vertical group and one horizontal. Seems a bit arbitrary. Why not a group of 4 horizontal?

Regards,

J1M.

[SamK]

I think I'm getting confused about which one is which.

I'm not familiar with Jenga.  For future reference I would prefer to use architectural references for the diagram types.
The least detailed type = Side Elevation (as in viewing the drawing of the side of a building)
The most detailed type = Plan Elevation (as in viewing the same building from directly above)

It will be helpful if previous contributors re-confirm their preference using these terms as it will avoid confusion.

I appreciate you taking the time to feedback comments.  As I see it at present using a group of 4 disks in a single orientation leaves a lot of unused space in the diagram and make it appear 'unbalanced' as it is difficult to integrate the LVM elements with the RAID Array based on the components /dev/sd[ab]2.

[RoboJ1M]

http://en.wikipedia.org/wiki/Jenga Jenga! 

I prefer Jenga Plan.

Side is simpler, but I've never seen a diagram like Plan before. It really can show everything there is to know about the secondary storage system.

J1M.

[SamK]

One criticism, the HDD (grey) layout. One vertical group and one horizontal. Seems a bit arbitrary. Why not a group of 4 horizontal?

Version 3 of Plan view is attached.
Instead of attempting to show all hard disks in the same elevation this version groups the hard disks into a grid configuration.

[SamK]

To save scrolling around the thread I attach what I intend to be the final versions for comment.  To prevent any confusion please indicate Plan or Side Elevation when referring to a diagram as it seems to have been unclear which type of diagram was being supported.

[poundjd]

Sam,
  I like the vertical approach better.  but both are really good at laying it all out.
-jeff