HP 3PAR RAID layout

[storageguy123]

Hi Guys ,

I have some queries about HP 3PAR RAID layout. Below is my points of interest.
I know when we create a virtual volume then HP 3PAR OS create logical disk in the background, and we have RAID protection at LDs level.
Below is my observation
1.If i create a fully provisioned volume without any snapshot, then my storage will create equal no of LDs , equal to the no of nodes in my storage. Please correct me if i am wrong.
2.But for a thinly provisioned volume i have observed that no of LDs are more , but still equally divided among all the nodes.But initially at the time of creating a thin virtual volume , how many LDs it will create? and of what size?. I have also observe that a volume is having different size of LDs(128MB and 256MB) why it is like this . On what facts 3PAR define the size of LD(on what factor it depends).
3.I have minimum allocation unit is a chunklet of 1GB but still i can create a volume of below 1GB so how it is happening may be because of regions. So i have region size equal to 128MB so can i create a volume of 128 also. Then how it will stripped in the backgroud so that it can have defined RAID protection.

Any reply will be highly appreciated..................

[Cleanur]

Have a look at the concepts guide, some of this is explained in there. The LD's will depend on the CPG growth size, but data is written in 16KB pages, regions and chunklets are larger structures. Think of a chunklet as a container for data as you would a physical disk on a more traditional array.

It's worth having a look at the older concepts guide as they occasionally have a few gems missing from the more recent versions

2.3.1 http://goo.gl/RctfwV
3.1.1 http://goo.gl/SYFeUN
3.1.2 http://goo.gl/Zadhpn
3.2.1 http://goo.gl/LcUL9d