How much faster is Raid0 compared to Raid1

WillSpengler · 13 May 2008 at 14:44

Just a simple question really.

Original plan was two 320Gb 7200.11's in Raid0 and two 500Gb F1's in Raid1.

But will the 320Gb drives be much faster in Raid0 than if I put them in Raid1 mode (so that if something did happen, I wouldnt need to worry about a pile of reinstalls).

I know that Raid0 is faster than drives used alone, and using a drive alone is faster than Raid1, but the question is, how noticable a difference will it be?

MikeHunt79 · 13 May 2008 at 14:45

I always thought raid 1 was faster?

WillSpengler · 13 May 2008 at 17:32

Isnt it:

Raid0 = Striped
Raid1 = Mirrored

?

MikeHunt79 · 13 May 2008 at 17:53

Cob · 13 May 2008 at 18:53

RAID1 can be a tad slower than a single drive.

Paracelsus · 13 May 2008 at 22:21

Cob said:
RAID1 can be a tad slower than a single drive.

Yeah if anything I'd expect it to be slightly slower, certainly no faster than a single drive.

I RAID1 with a pair of drives, benching beforehand showed one drive getting a slightly better transfer speed average, now in RAID1 the graph/speed resembles a mix of the two drives, the speed is inbetween the two seperate speeds and the speed graph's shape has prominent features of both

JIM_BOB7813 · 13 May 2008 at 23:01

Here's my benchmarks for 2x saegate 320gb 7200.10's in raid 1 and raid0
RAID 1

RAID0:

WillSpengler · 14 May 2008 at 00:16

Wow, looks quite an impressive difference. Was it a noticable difference in practice tho?

bledd · 14 May 2008 at 09:20

in 'theory' raid0 is twice the speed of a single drive, and raid1 'should' be slightly slower than a single drive

the speed difference is noticable between raid0 and raid1

NickK · 14 May 2008 at 09:28

The obvious difference is the purpose.

Raid 0 is for speed, if one of the drives fail the volume cannot be recovered.

Raid 1 is for availability, if one of the drives fail then the volume can still be accessed.

Either way - all forms of RAID are for availability as they're not a substitute for a backup regime.

WillSpengler · 14 May 2008 at 10:40

I'd say its a pretty good way of backing up

Not 100% because it could be possible for both drives to die, but im guessing it isnt that likely

I think I may just go with two Raid1 arrays, I dont think the speed would be that noticable in practice, been using a WD Raptor for a few years and it never seemed that much quicker than a normal 7,200 drive.

rpstewart · 14 May 2008 at 11:30

WillSpengler said:
I'd say its a pretty good way of backing up

Far from it. RAID will only provide protection against a hardware failure of a drive, there are plenty of other more common situations where a backup will allow recovery but RAID won't.

WillSpengler · 14 May 2008 at 11:45

The only hard drive failures I have ever encountered have been mechanical failure. What else could cause the loss of data? (genuine Q)

rpstewart · 14 May 2008 at 11:58

File deletion, either malicious or accidental
File system corruption (although this is very rare with NTFS)
Controller or motherboard failure
Fire
Flood
Theft

bledd · 14 May 2008 at 11:58

the raid controller failing.. a corrupt memory stick gashing the data on the drives

you should always have at least one backup on another drive / media

raid1 in the home is generally pointless imo..

edit.
err, and what he said ^^

Toytown · 14 May 2008 at 15:30

raid1 'should' be slightly slower than a single drive

Depends on the controller, most motherboard based RAID systems will see this kind of performance, but decent RAID controllers that normally have a dedicated CPU/RAM will offer significantly faster read performance than that of a single drive.....write performance will be the same however.