topic Re: EVA5000 RAID5 Calculation in Disk Enclosures

EVA5000 RAID5 Calculation

Phil Daws_4 — Wed, 13 Apr 2005 04:37:59 GMT

Hi,

i am trying to extract details from the Management Server using SSSU and cannot work out how to get the available storage for a RAID5 disk group.

Here is a dump from SSSU :-

\Disk Groups\Default Disk Group information:
Name : \Disk Groups\Default Disk Group
Operational_state : Initialized - Warning
Total_disks : 58
Total_capacity : 3688.08GB
Occupancy : 3529.70GB
Occupancy_Alarm_Level : 85 %
Disk_Failure_Protection_Level :
Double
Actual_Protection_Level : Double
Requested_Protection_Level : Double
levelingstate : inactive
levelingprogress : 100
rssdiskstate : none
Comments : 72GB 15k disks

Now if I take Total_Capacity - Occupancy I get a figure of 158.38 which is ~ the figure the web interface is reporting for RAID0 eg.

Total: 3688.08 GB
Available:
Vraid0 154.75 GB
Vraid1 77.37 GB
Vraid5 123.77 GB
Total disks: 58

So how do I get the RAID5 figure?

TIA.

Re: EVA5000 RAID5 Calculation

Uwe Zessin — Wed, 13 Apr 2005 08:20:03 GMT

It is right in front of your eyes ;-)

:: Vraid5 123.77 GB

VRAID-5 uses a 4D+1P mechanism, so if you take the space from VRAID-0, you can also calculate:
154.75/1.25 = 123.8

Re: EVA5000 RAID5 Calculation

Bostjan Kosi — Wed, 13 Apr 2005 08:23:01 GMT

Eva RAID calculation:

VRAID0= 100%

VRAID1= 50%

VRAID5= 80%

Eva crates VRAID5 with 4+1 scheme meaning you loose 20%...not as you were used to...capacity of one drive...

BR
B.