CVUI - Available space for LUNs

[rob nolen]

Hi,

First time poster.

I've recently become responsible for an N-Class system that has 2 va7400 enclosures in it.

Each one has the max 15 disks, 73G each.

First question: How can I find out how much actual storage is available from each disk? Parity and metadata eat up some space, and I'm just wondering how to determine the amount.

Second question: I ran cvui to look at see how much space is available for LUNs. It shows me the following output:
Redundancy Group = 1
Unallocated (Available for LUNs) = 327.748 GB

Redundancy Group = 2
Unallocated (Available for LUNs) = 336.134 GB

Does this show the free (non-LUN) space for each enclosure?

Thanks for your help with what I'm sure will be lots of questions.

I am currently badgering my boss to approve the Storageworks Class and SAN class so I can get a little more familiar with all of this.

[Luk Vandenbussche]

Rob,

In a VA7400 al the data is striped over the disks (RAID0+1 or Autoraid,depends on the settings) So it is not relevant to speak about free space on each disk. You have to check at the free disk space.

A VA7400 has two redundancy group (disk groups). In the first RG you have 327 GB free and in the second you have 336 GB free.

[rob nolen]

Luk,

Thanks for your reply. I guess what I'm trying to ask is, if I add a 36GB disk to my array, how can I determine how much is usable.

Also, I'm still a little hazy on the redundancy grou thing. Is that a logical partition of the drives in the two enclosures?

[Torsten. · Accepted solution]

The VA74x0 has 2 redundancy groups - that means 2 internal busses. One bus are the odd numbered drives and one controller, the other group are the even drives and the other controller - mainly for performance reasons.

See the attached document.

Expect around 75% percent capacity of a disk to use, this depends of a lot of internal settings, e.g. number of hotspare drives.