Which is better RAID 1 or RAID 5?

[mbaldwin]

WE have a new Dell 6550 server being setup with win2k. It has 5 internal 73gb drives (maxed out). The first two are a mirrored pair, RAID 1. My question is how to best setup the last three. Is a RAID 5 better than RAID 1 with a hot swap spare? The net space is the same. We'll put two data paritions on it for two applications. Second question is should you allways mirror the OS? Can a raid 5 be better using all drives to net more free space? Is there a downfall?

 

[ashpp]

> Is a RAID 5 better than RAID 1 with a hot swap spare?

RAID 1 200% Read speed/100% write speed
RAID 5 >200% Read speed/write speed depends on raid processor & number of disks so roughly 50%-3200%

RAID 5 is more efficient with disks obviously

> Second question is should you allways mirror the OS?

No, the main advantage is that raid 1 is that its so easy to rebuild with a possible 0% downtime and low rebuild time.

> My question is how to best setup the last three. Is

I would go for Raid 5.

 

[Big0range]

Space will be different, also. RAID5 will give you 140g usable space, RAID1 will give you 70g space. I would almost always recommend a RAID5 for the non-system paritions - you have better space and usually better performance; with RAID1 you can read from both drives at the same time, then write back to one. With RAID5, you read from each drive at the same time and can write to each at the same time as well.