Which RAID?

dokko · 5 Oct 2007 at 13:02

Hi, never done it before, and was wondering if its worth it?

Which is the best for speed, drive failure isn't that important as long as i don't increase my chances of it happening.

Also is it a complex thing to do, or is it just a case of buying an exact copy of my old HD and changing a few settings?

Cheers.

semi-pro waster · 5 Oct 2007 at 13:14

Raid0 is the quickest because you are striping data across two drives but of course you are increasing the risk of data loss - you rely on two drive to continue to act as one (now it still isn't a huge risk but you have increased it significantly statistically).

It might help you to read the sticky about the various Raid levels or do a Google search because the information is available if you care to read up.

rpstewart · 5 Oct 2007 at 13:15

RAID0 will allow you to get a higher sustained transfer rate than a single drive but since your data is across two drives there is an increased risk of data loss since a failure of either disk will lead to a loss of all the stored data. You could use 3 disks in RAID5 to give approximately the same read performance as a 2 disk RAID0 array but you need to spend a fair whack of cash for decent RAID5 write performance.

Actually implementing RAID0 will require a complete reinstall of the OS and all apps since creating the array will wipe both disks.

Mr Jack · 5 Oct 2007 at 13:49

rpstewart said:
You could use 3 disks in RAID5 to give approximately the same read performance as a 2 disk RAID0 array but you need to spend a fair whack of cash for decent RAID5 write performance.

What do you mean by decent write performance? A 3-disk RAID5 array will give better write performance than a single disk, for example. Tom's

dokko · 5 Oct 2007 at 14:09

semi-pro waster said:
Raid0 is the quickest because you are striping data across two drives but of course you are increasing the risk of data loss - you rely on two drive to continue to act as one (now it still isn't a huge risk but you have increased it significantly statistically).

It might help you to read the sticky about the various Raid levels or do a Google search because the information is available if you care to read up.

I have been as part of my IT course, but wanted to hear what people who have done it thought, i feel you get a much better picture of it from this level.

dokko · 5 Oct 2007 at 14:11

rpstewart said:
RAID0 will allow you to get a higher sustained transfer rate than a single drive but since your data is across two drives there is an increased risk of data loss since a failure of either disk will lead to a loss of all the stored data. You could use 3 disks in RAID5 to give approximately the same read performance as a 2 disk RAID0 array but you need to spend a fair whack of cash for decent RAID5 write performance.

Actually implementing RAID0 will require a complete reinstall of the OS and all apps since creating the array will wipe both disks.

Well i wanted to do it cheap.

I've got a WD Caviar, 250gb SATAII 16mb HD right now, i guess i need to buy a clone, although i've seen one on OC which is designed for RAID, would it be best to get that or just keep them both identical?

As for a reinstall, that's not a problem i suppose as i was thinking about going for Vista anyway.

rpstewart · 5 Oct 2007 at 14:35

Mr Jack said:
What do you mean by decent write performance? A 3-disk RAID5 array will give better write performance than a single disk, for example. Tom's

Yeah, that's with a £300 dedicated controller card though. If you use the RAID5 capability provided by motherboard controllers you're looking at 25Mb/s tops.

Little_Crow · 5 Oct 2007 at 14:40

The drives should not need to be identical, but:

Your performance will only be as good as the slower drive, in RAID0 the data has to be retrieved from both drives, so nothing can happen until both parts have been retrieved.

The size of your RAIDed partitions can only be as big as the smaller drive.
If you have a decent RAID card then you could use any left over space but it wouldn't benefit from the performance increase RAID0 offers

dokko · 5 Oct 2007 at 15:01

I need a RAID card???

rpstewart · 5 Oct 2007 at 15:07

dokko said:
I need a RAID card???

If you have RAID support on your motherboard (which virtually all have now) then no you don't need a card.

dokko · 5 Oct 2007 at 15:11

rpstewart said:
If you have RAID support on your motherboard (which virtually all have now) then no you don't need a card.

This one is less than 2 years old, but it doesn't matter, RAID would come with a new OS, which would only be done if i get a new mobo anyway.

I do remember this thing though having RAID capabilities as that was the 1st time i'd ever heard of it, and until this week or so never really knew what it meant.

Mr Jack · 9 Oct 2007 at 14:23

rpstewart said:
Yeah, that's with a £300 dedicated controller card though. If you use the RAID5 capability provided by motherboard controllers you're looking at 25Mb/s tops.

That was true of older mobos, it's not true of more recent ones: link - this covers the ICH8R, but I sincerely doubt that the ICH9R found on boards such as the GA-P35C-DS3R in my machine are going to be worse.

stealthgeek · 9 Oct 2007 at 17:39

true, but look at CPU usage - 33%? I suppose if its just a media/internet/email machine its OK, wouldnt want that much usage personally.

Mr Jack · 10 Oct 2007 at 10:12

stealthgeek said:
true, but look at CPU usage - 33%? I suppose if its just a media/internet/email machine its OK, wouldnt want that much usage personally.

You don't get that much in normal usage though; that's a peak value (as the article says they saw much lower values in more realworld testing). Also, if, like me, you have a quad core that's even less significant.