Joined
·
3,718 Posts
Hey guys dumb question
what's raid5 used for?
What does it do?
what's raid5 used for?
What does it do?
Raid 5 ??
1 - 8 of 8 Posts
Joined
·
652 Posts
In short it combines striping with parity check bits that are spread out over the disks, a minimum of 3 drives is needed. The advantage over RAID 0 is that 1 drive can fail and the array will still function (more slowly).
The main disadvantage is that the check bits require quite a bit of processing which on motherboard based RAID controllers and cheaper RAID cards is carried out by the host computers CPU, this makes it a poor choice unless you invest in a decent RAID controller.
RAID 5
The main disadvantage is that the check bits require quite a bit of processing which on motherboard based RAID controllers and cheaper RAID cards is carried out by the host computers CPU, this makes it a poor choice unless you invest in a decent RAID controller.
RAID 5
Joined
·
3,718 Posts
So if I have 3 1tb drives, how much storage will show in my OS?
I'm about to make a little server box
so thts why I'm asking
I'm about to make a little server box
so thts why I'm asking
Joined
·
22,856 Posts
you will get slow writes if you use onboard controllers as the CPU has to calculate the parity bits, if you are going to do RAID-5 then get a dedicated controller like the dell PERCi5
My RAID-5 arrray 4x1TB WD green drives
![]()
My RAID-5 arrray 4x1TB WD green drives
Quote:
Isn't it just N-1?
RAID5 read performance is near n-1.
RAID5 write performance is bad... something like 20-80MB/s with host-based RAID controller.
RAID5 is good for media storage since its usage would be write once, read many.
Originally Posted by moward  you will get 2TB with 3 x 1TB drives space efficiency for RAID 5 is calculated using 1-1/n where n is the no. of drives. |
RAID5 read performance is near n-1.
RAID5 write performance is bad... something like 20-80MB/s with host-based RAID controller.
RAID5 is good for media storage since its usage would be write once, read many.
Quote:
Quote:
moward is talking efficiency, not capacity.
The capacity of an n-drive RAID5 array is:
(no of drives - 1) x capacity of smallest drive
= n-1 (assuming all drives equal size)
The storage efficiency of an n-drive array the array is:
number of drives containing data (n-1) / total number of drives
= (n-1)/n (assuming all drives equal size)
The efficiency is an indicator of how much space you have to pay for in order to store a certain amount of data.
= 1 - 1/n
Originally Posted by moward space efficiency for RAID 5 is calculated using 1-1/n where n is the no. of drives. |
Quote:
Originally Posted by DuckieHo Isn't it just N-1? |
The capacity of an n-drive RAID5 array is:
(no of drives - 1) x capacity of smallest drive
= n-1 (assuming all drives equal size)
The storage efficiency of an n-drive array the array is:
number of drives containing data (n-1) / total number of drives
= (n-1)/n (assuming all drives equal size)
The efficiency is an indicator of how much space you have to pay for in order to store a certain amount of data.
= 1 - 1/n
1 - 8 of 8 Posts
Join the discussion
