Given how hard drives seem to have a propensity for failing these days I thought Id set myself up a RAID array that mirrors my existing hard drive so Ive got duplicated data, and if the primary hard drive ever goes kaput all of the data will be backed up. Ive a few questions about this... firstly is there any major performance hit from mirroring data in this way? Also do the drives have to be blank to get it set up and running or can I simply whack in a duplicate drive and have it copy all of the current info on my hard drive across and pick up from there?

I like to think Im fairly savvy about hardware but RAID is something Ive never even attempted before so any advice would be very much appreciated.

My motherboard is an MSI P965 platinum if it makes any difference and the hard drive Ill be needing mirrored is a WD Caviar SE16 250GB SATAII one.

For it to work effectively you need an identical drive, Ive never operated a mirrored array myself (only striped) but Im pretty sure that you can install one drive with data on and have it rebuild a mirrored array the same way you would do if during the arrays operation one of the drives packed in.

Youll find there are no negative performance hits to having a mirrored array; write times remain the same as data is written once on each drive but in fact I think read times are improved because data is read from both drives. Never tried it myself but this is what I gather.

Im hoping to go back to a RAID setup in my next build, either a 10,0+1 or a 5. Ive not thought it all out yet.

overcome slow raid by getting a 500gb mirror & 2x 250gb to strip - Raid 0+1

Raid 0 is strip
Raid 1 is mirror

Raid10
Raid 0+1 is Strip & mirror
Raid 1+0 The mirror is stripped!

write preformance will stay the same, but read will be faster... (as both drives are the same it can read some from each drive)

nope, drives dont have to be blank, should be able to set it up and have it copy the stuff accross with most raid... but google the ones youre going to get just to check

Quote from: Chris Hfirstly is there any major performance hit from mirroring data in this way?

No as Clocked mentions, you generally wont lose perfomrance.  More so the case in hardware raid rather than a raid configured within windows (sofware raid).

Quote from: Chris HAlso do the drives have to be blank to get it set up and running or can I simply whack in a duplicate drive and have it copy all of the current info on my hard drive across and pick up from there?

Depends, depends on the RAID controller functionality.  Cheaper motherboard raid controllers generally only have the functionality to create a striped or mirrored array from scratch.  Not from an existing source.  You may be able to.

I find the best trade of between speed and reliability is Raid 5.  Striping with Parity . However it is more expensive to set up and effectively you sacrifice one disk (as you would in mirroring) in the cost.  That though would require 3 fresh hard drives minimum.  If a drive dies, you replace it an repair the array, simple.

The manual from the mobo suggest I may be able to create a RAID volume from an existing disk using some Intel Matrix Storage Console software, it says it wont touch the data on the existing disk but Im rather paranoid so Ill back everything up across the LAN just to be sure, although for it to work I was supposed to have the BIOS set for RAID before I installed XP, and I was also supposed to install a RAID driver during XP installation. I dont know why these had to be done when I first set the system up, I hope I actually did it and didnt skip them.

Quote from: Clockd 0NeFor it to work effectively you need an identical drive,

Not quite, identical capacity drive would be more exact, but even that isnt the whole story, there is the possibility of mirroring partitions, or used to, so you might mirror a 500gb partition onto a 750mb drive. I have only seen this in operation once, a long time ago and TBH its cheaper and more efficient to do them as a pair of equal sized drives. You have a theoretical very slight hit on performance writing on most built in raid, it has to write to each disk, but this may not be noticeable at all. As you say though access times should be faster if its implemented properly.

Im just browsing the MSI forums now and lots of people are reporting lots of issues with RAID. My system has been rock solid stable so far so Im loathe to mess around with it now... Im wandering if it might be better to just get a 250GB LAN hard drive enclosure (or a 500GB to allow for a bit of future proofing) and do a manual backup every so often, and investigate RAID properly in my next build. I understand something like Acronis Trueimage can back up my data on the fly to a LAN drive with almost no noticable slowdown in speed so that seems a good alternative. Im not sure if I can be bothered with the hassle of perhaps fooking all of my data and having to spend hours re-installing everything. Kind of sat on the fence at the moment.  

pah!

theyre be loads of noobs bashing raid because they did something stupid like format there drives and then blame it on the computer, not themselvs

also, theres always a queue of people just waiting to bash raid and tell you how crap it is.... Ive always used striped raid in my main rig for the past 5 years or so... its the fastest, but least safe... Ive got 5 drives like that right now... so have 5 times the chance of losing everything... but ive never had a single problem !  even when i disconected all the drives and forgot the order they were in !

Quote from: Serious

Quote from: Clockd 0NeFor it to work effectively you need an identical drive,

Not quite, identical capacity drive would be more exact, but even that isnt the whole story, there is the possibility of mirroring partitions, or used to, so you might mirror a 500gb partition onto a 750mb drive. I have only seen this in operation once, a long time ago and TBH its cheaper and more efficient to do them as a pair of equal sized drives. You have a theoretical very slight hit on performance writing on most built in raid, it has to write to each disk, but this may not be noticeable at all. As you say though access times should be faster if its implemented properly.

I say effectively because the ideal scenario is two drives of equal spec and performance. RAIDs are more reliable when using the same drives rather than a mish-mash IME.

Quote from: Serious

Quote from: Clockd 0NeFor it to work effectively you need an identical drive,

Not quite, identical capacity drive would be more exact, but even that isnt the whole story, there is the possibility of mirroring partitions, or used to, so you might mirror a 500gb partition onto a 750mb drive.

In my experiance of setting up a couple of SBS servers every month drive space being exact doesnt make a difference.  It you have a 250 and 300 then your just going to end up with 50 gig you cant do anythng with.  Thats it.

But yes I am anal about using the same brand and size of HD if possible.  It just isnt allways.

Thanks for confirming, As I said the last time I seen a system like that it was a long time ago

Quote from: Clockd 0Ne

Quote from: Serious

Quote from: Clockd 0NeFor it to work effectively you need an identical drive,

Not quite, identical capacity drive would be more exact, but even that isnt the whole story, there is the possibility of mirroring partitions, or used to, so you might mirror a 500gb partition onto a 750mb drive. I have only seen this in operation once, a long time ago and TBH its cheaper and more efficient to do them as a pair of equal sized drives. You have a theoretical very slight hit on performance writing on most built in raid, it has to write to each disk, but this may not be noticeable at all. As you say though access times should be faster if its implemented properly.

I say effectively because the ideal scenario is two drives of equal spec and performance. RAIDs are more reliable when using the same drives rather than a mish-mash IME.

but NOT the same batch, since then you are more likely to have a symultanious faliure and even RAID 5 cant cope with 2 drives going funbags up at the same time.

Many people get around this by buying identical spec drives from different retailers in the hopes of getting drives which are at least some way apart in the production run.

Thats good insight Id never considered, and probably what caused the eventual downfall of my Deathstar raid 0... cheers for that!

Well the rig has been running for about 12 months now so even if I order an identical drive I imagine they would be some way apart in batch numbers. That is an interesting point though, Id never have considered it before.