Why is RAID fast?

Guest2 · 21 Sep 2009 at 11:19

I dont really understand raid but know that its good for if a drive dies, as the other will just take over. What makes raid faster than running a single drive?

I would have thought that raid would be slower as both drives are reading/writing data at the same time

Is there any point in setting up RAID (if its possible) on 2 500gb different model drives. Would i lose 500gb but gain speed and reliability, if one dies obviously

Guest2 · 21 Sep 2009 at 11:22

So if one of the drives die then you lose one half of the file? Surely not

I think at work our file server has 8 drives in raid where the data is 'striped' accross them? If one dies does it just shift the data to the others before?

Guest2 · 21 Sep 2009 at 11:26

Paul11 said:
if one drive dies, you lose all the data on both drives

a bit risky isnt it? We must be using a different type of raid. One of our disks died a few weeks ago and it was replaced and everything went on as normal

Guest2 · 21 Sep 2009 at 11:37

Thanks. Think ill stick with a velociraptor (when it arrives) as my primary, 2 500gb drives for storage and a 250gb drive for backing up the velociraptor every few weeks
(and a 1tb external for backup)

Guest2 · 21 Sep 2009 at 12:15

paradigm said:
I would imagine that in a corporate environment, you'll be running something like RAID5, RAID6, RAID10, RAID50 or RAID60.

Both speed and redundancy advantages, without the risk of data loss for one (or more, depending on RAID level) drives.

From my brief reading i thought there was only raid 0 (writes 50/50, faster but data loss on both),1 (writes accross all but lose disk space) and 5 (minimum 3 drives, can only lose one drive but a bit faster)

Ill look into raid 6, 10, 50 and 60...

edit - reading this http://en.wikipedia.org/wiki/Nested_RAID_levels#RAID_60_.28RAID_6.2B0.29
looks like we are using raid 60

Guest2 · 21 Sep 2009 at 12:25

bledd. said:
you'll be likely using raid5 in work

data is striped across many drives

http://en.wikipedia.org/wiki/RAID

I thought only one drive can fail though in raid5. Im sure my boss said 2 can fail

(from raid 60 on wiki) any two drives can fail without data loss and up to four total as long as it is only two from each RAID6 sub-array.

Guest2 · 21 Sep 2009 at 13:33

Stonedofmoo said:
Basically you require dedicated hardware cards for the other types of RAID. On home setups you only see RAID 0/1/5

Mate has got a hardware card that can do RAID 10. Doesnt it depend on what motherboard you have as to what types of raid can be done?

Think my S939 DFI ultra-D board can do raid 0 and 1, not sure about 5