RAID5 Problem With HP Storage System 6

[Danilo Pellegrini_1]

Hy, I have this system configuration:
- NetServer LC III with one HP PCI Raid controlle with one channel. In this
system I have installed 3 Disks Hot Swap with 4 GB of capcity FOr Disk. The 3
Diks are in RAID5 COnfiguration.

Now I have installed the HP Storage System 6 with 3 Disks Hot Swap with 9 GB of
capacity for disk.

Well, with HP NetRaid Assistant I have join the 3 new disks to the Logical Unit
of previus RAID5 system, with thi option "ADD SPACE". All it's ok BUT the total
capacity of my system is'nt correct.... Why?

I have new space, but 3 disk of 9 gb is 27 GB, RAID5 use about 33% of disk
space for parity...I must have 19 GB of space BUT I HAVE ONLY 12 GB OF FREE
SPACE....
I DON'T KNOW WHY....?

Thank You very Much!
Danilo

[Erwin Dillard]

Assuming this is the AutoRAID disk array. Active hot spare space will be
reserved as the size of the largest disk in the array, next Parity space is
reserved, then RAID 0/1 and controller overhead space is reserved.(this is
capacity used by the array to support data migration and maintain performance.
This space will vary as disks are added or removed). So you will not see all
the disk space on all the disk, some is used for overhead and data redundancy.