RAID advice...

radiospan

Hi,

I've needed a bigger hard drive for a good while now, my current 60GB (this one) just isn't big enough.

I was thinking of buying a 120GB from Komplett, but after reading an article about RAID, I was wondering if a RAID 0 setup might be a better idea.

For RAID0, do both harddrives have to be identical? Would it be possible to combine, say, my 5400RPM 60GB drive with a 7200RPM 80GB, or would I be better off just buying a new harddrive and keeping my 60GB as a separate drive D?

Lump

For the raid to work, ie that it splits the files between the drive in order to write faster well then yes the drives need to be the same. You can get cards that will give you a couple of extra IDE connections, however the drives will appear as two seperate drives and not raid-ed....


John

Mutant_Fruit

Apart from that, i'd like to point out a raid 0 is VERY unsafe. If one drive dies, BAM, EVERYTHING is gone and NOTHING is recoverable.

Only use that if you absolutely have to.

unkel

Originally posted by Mutant_Fruit
Apart from that, i'd like to point out a raid 0 is VERY unsafe. If one drive dies, BAM, EVERYTHING is gone and NOTHING is recoverable.

Only use that if you absolutely have to.

Same risk applies if you use one drive on its own. In both cases, it is important to back up all important data

The beauty of RAID0 is the speed. IDE harddisks have been the bottleneck in PC's for many years now. It's nice to remove most of this bottleneck

Nobody HAS to use RAID0

Mutant_Fruit

Not quite, if a single drive becomes corrupt (and starts dying) its a Helluva lot easier to recover off it.

If a raid 0 starts corrupting, most of the time you can kiss everything goodbye. I was just pointing out that raid 0 has no failsafe, and thus i wouldn't recommend it.

A friend of mine has a raid 5 (four 250gb's and one is a "backup"). This means he has about 1tb of usuable space, and any single drive can die in that array, and as long as he replaces the dead one before a second dies, nothing is lost. Thats expensive, but safe

unkel

Of course. I bet though that the vast majority of home PC users that use on-board raid, use RAID0

If you have an image backup of your system drive and one disk should fail, just replace it with a new one, rebuild the RAID and restore the image. All non system drive data should be backed up anyway

Only pain is to wait for RMA, same as if a single drive fails

Mutant_Fruit

The benfits of raid are speed and reliability, but i fail to see the point in gaining speed, if you are 4x more likely to lose everything.

The odds of you losing all your data on 2 seperate hardrives are (for example) 1/4. In raid, only one has die for you to lose everything, so the odds are 1/2.

I fail to see the benefits of raid in that situation.

unkel

Originally posted by Mutant_Fruit
The benfits of raid are speed and reliability

NO

The benefits can be speed AND/OR reliability

The only advantage of RAID0 is speed. As I've stated backups are crucial though

neokenzo

I'm kinda new in this Raid thing. I just bought 2 160GB SATA drive. How do I use Raid, as in how do I set it up? Whats the different between Raid0 and Raid1? Also my mobo comes with a primary and secondary SATA and also 2 other SATA ports. Which one do I connect my hdd to? Do I need any additional connectors for Raid?

joePC

Get your self a SATA Raid card there very cheap and two 120GB-SATA Hdd you will never look back.

SATA Hard Drives

RAID Card

Thanks joePC

unkel

Which drives did you buy and what mobo do you have? What other drives do you want to connect, i.e. optical disks and/or ATA hard disks? What OS?

unkel

Those drives are not that cheap there JoePC - got myself two of those excellent drives (160GB version 8MB cache) for about €120 each about 4 or 5 weeks ago

joePC

neokenzo : Make sure you have SATA enabled either a jumper on the MB or a setting in the BIOS, connect the two SATA Hdd's to there ports and boot @ the screen where it detects the Hdd press F4 to enter the setup from here you can create a RAID Array / Set, Now install you OS, you may need the SATA drivers when installing the OS, you just use a floppy disc, Thats everything.

Thanks joePC

joePC

unkel :

Those drives are not that cheap there JoePC

I know heres what I said,

Get your self a SATA Raid card there very cheap

Thanks joePC

unkel

I understood your post alright JoePC and the drives you recommend are excellent - I can vouch for them

Just urging people to shop around. Got mine from overclockers at a special deal. Normally jes-computers would be pretty hard to beat on price, especially now we've all been made aware, thanks to some boardies, that we can use a banktransfer (€0.75) to avoid heavy paypal transaction costs

joePC

True, True, Overclockers are a very good company, never dealth with Jes-computer but from what I hear they are very good.

Thanks joePC

unkel

Originally posted by joePC
never dealth with Jes-computer

Me neither but they would be my first preference next time if they keep beating Komplett and overclockers on price. Have not heard a story yet on RMA's though. Komplett have been pretty slow but pretty good to me over the years on RMA's

Slightly off topic: just a wee example of how we're all ripped off in the high street: I'm looking for a NB HS to replace my noisy mobo's HSF. Standard Zalman costs €3.75 or abouts online. Peats charge €15 for the same thing :mad:

I would be eager enough to go into Peats to buy it and pay the full price, but fortunately I rang up first. After the usual malarky about people not having a clue what you're on about, the conclusion is that it is not in stock

I don't think this message is getting through at all in Ireland. Say we don't take tax into consideration, then a part costing €3.00 selling for €3.75 generates a 25% markup. The same part in Peats generates a whopping 400% markup :mad:

po0k

if you've got ~€230 get 2 120Gig sata drives and a decent PCI bootable sata RAID card, if you want to use linux I suggest staying away from Promise or highpoint.
Setup your 2 drives in RAID0 for the system, transfer over whatever you need off the 60Gig and use that as backup, possibly in conjunction with optical backups (CDRs).
Alternatively, if you just need read speed, data security and don't need more than 120Gigs, put the two drives in RAID1 (mirroring).

If you've got ~€430, get 4 120Gig drives, a 4-channel sata raid card and setup a RAID0+1 array, 240gigs striping and mirroring, 4x read speed over 1 drive, 2x the write speed, data integrity if a drive dies.

neokenzo

I'm still confuses. I have more questions

What does a RAID card do?
What are Promise and Highpoint?
Still dont understand the difference between RAID0 and RAID1

Dempsey

Originally posted by neokenzo
I'm still confuses. I have more questions

What does a RAID card do?
What are Promise and Highpoint?
Still dont understand the difference between RAID0 and RAID1

This will explain the ideas and different RAID types and how they are implemented

http://www.uni-mainz.de/~neuffer/scsi/what_is_raid.html

Promise and Highpoint make PCI RAID Controller Cards.

Mutant_Fruit

i strongly advise only running raid with a hardware controller. Otherwise if you decide to upgrade OS, or hardware, you will probably not be able to transfer the raid.

Dempsey

Originally posted by Mutant_Fruit
i strongly advise only running raid with a hardware controller. Otherwise if you decide to upgrade OS, or hardware, you will probably not be able to transfer the raid.

Same Here. Id only recommend using Hardware. Has anyone ever tried software?

neokenzo

Thanks Dempsey for the link. I've read it and I think I understand a bit what RAID is. It seems troublesome to have something that might not work if you need a reformat or upgrade your pc. Surely there's not much difference running 2 SATA hdd compared to say RAID0?

Dempsey

Originally posted by neokenzo
Surely there's not much difference running 2 SATA hdd compared to say RAID0?

RAIDing two drives is what sets it apart from just being 2 drives independent of each other. In a RAID setup both disk are accessed at the same time giving roughly twice the transfer rate( In RAID 0). In a normal setup one drive is accessed at a time but you only have the effective storage space of one drive cos the files are written to both drives.

unkel

That's the most concise explanation of RAID I've seen Demsey

Indeed interesting that RAID0 is not really RAID

Dempsey

Originally posted by unkel
Indeed interesting that RAID0 is not really RAID

Dont confuse him with that one

neokenzo

Thanks for putting that in plain English Dempsey
Still have a couple more question though

1. RAID1 basically mirror both hdd? Does that mean if I have 2 x 160GB, it will only show 160GB in windows unlike RAID0 that shows 320GB?
2. If I set RAID0, means I cant change/upgrade/replace windows or hardware? Any hardware? Can RAID0 be backup to rectify this?
3. When you say hardware, I presumed you meant the RAID card? I take its a PCI card? Is there any other type I can use? Dont have a free PCI slot.

Mutant_Fruit

raid cards only come in PCI flavours. And trust me, you'll save yourself a lot of hassle in the future if you go with a hardware(PCI) raid controller.

If you read the other RAID thread, you'll know what i mean.

Dempsey

Originally posted by neokenzo
Thanks for putting that in plain English Dempsey
Still have a couple more question though

1. RAID1 basically mirror both hdd? Does that mean if I have 2 x 160GB, it will only show 160GB in windows unlike RAID0 that shows 320GB?
2. If I set RAID0, means I cant change/upgrade/replace windows or hardware? Any hardware? Can RAID0 be backup to rectify this?
3. When you say hardware, I presumed you meant the RAID card? I take its a PCI card? Is there any other type I can use? Dont have a free PCI slot.

1. Basically Ya

2. You can but if either of the drives fail that means your screwed. The same problem with a single drive. Ya just cant replace either of the drives without reformatting. This is what unkel is on about. In a true RAID setup if a drive fails the data isnt lost because of the parity data. The failed drive can be replaced and the information rebuilt onto the drive from the information and the parity contained on the rest of the disks in the RAID array.(e.g. RAID 4 and 5)

3. Yes, PCI or onboard. Dunno about anyone other type of RAID controllers.

neokenzo

How do I set up RAID4 or RAID5?

Will ghosting my system a good form of backup incase the RAID0 goes bad?

Mutant_Fruit

For raid 5 (the one i'd recommend, as it provides fail-safe) you need 5 identical drives, and id advise a hardware controller card.

Just hook em up and format em into raid 5, and your done.

Capt'n Midnight

No you don't need 5 drives for raid 5
you need 3 or more drives
eg: if you have two drives the the third will be the difference between the first two (XOR) - and any missing drive could be recreated that way.
so any one drive is redundant.
total space =DriveSize x (no drives -1)

[ If you did it with two drives then you are simply mirroring the drives and that's called RAID 1 ]

Software raid - in the windows world you can only do this with SERVER or hacks - mirroring is handy if slow.

hardware raid - until recently there were two realistic options.
a / Mirror two large IDE drives using a promise controller
b / Hot Swap RAID 5 SCSI controller

option a is very cheap / chearful - lots of space
option b means you can swap the drives out without rebooting - and in a lot of cases you could have a hot spare there two - so once the volume has been rebuild by the card automatically then you have RAID again.

One thought - what if the RAID card dies ?
Not sure if an IDE raid controller mirroring drives means the drives would then be able to be read on another controller - but I'd be dead certain a RAID 5 stripped drive would be extrememly difficult to read if you didn't have a similar controller

astrofool

raid 5 has a minimum of 3 drives, and most onboard raids, and add on cards do not support (most). You'll need to look for a card that specifically supports it, though we could see it filter down now as more sata ports are added to motherboards.

po0k

you can do software RAID5 but all the XOR calculation will be done by your host CPU and disk I/O transfers will be slower than a hardware RAID5 array.
Totally depends on what your machine will be doing and whether you envisage ever needing to move the array to another machine.

po0k

Originally posted by Capt'n Midnight
No you don't need 5 drives for raid 5
you need 3 or more drives
eg: if you have two drives the the third will be the difference between the first two (XOR) - and any missing drive could be recreated that way.
so any one drive is redundant.
total space =DriveSize x (no drives -1)

[ If you did it with two drives then you are simply mirroring the drives and that's called RAID 1 ]

Software raid - in the windows world you can only do this with SERVER or hacks - mirroring is handy if slow.

hardware raid - until recently there were two realistic options.
a / Mirror two large IDE drives using a promise controller
b / Hot Swap RAID 5 SCSI controller

option a is very cheap / chearful - lots of space
option b means you can swap the drives out without rebooting - and in a lot of cases you could have a hot spare there two - so once the volume has been rebuild by the card automatically then you have RAID again.

One thought - what if the RAID card dies ?
Not sure if an IDE raid controller mirroring drives means the drives would then be able to be read on another controller - but I'd be dead certain a RAID 5 stripped drive would be extrememly difficult to read if you didn't have a similar controller

Just RMA the card and setup the array in the identical replacement with the same stripe and cluster sizes I'd imagine.

po0k

Originally posted by Mutant_Fruit
For raid 5 (the one i'd recommend, as it provides fail-safe) you need 5 identical drives, and id advise a hardware controller card.

Just hook em up and format em into raid 5, and your done.

:eek:

....

He's not running an enterprise file server ffs.
That'd cost ~€700-800 for a decent 4-channel sata hardware RAID5 controller + 4 120gig 7200rpm sata drives.
Tonnes more if you went scsi or FCAL.

neokenzo

Well at the moment I have 2 160GB SATA hdd. Dont think I could get another 1-2 more. So it looks more lightly that I have to set it as RAID0 if I want it to be RAIDed. I'm still wary about it though. I wouldnt want one of my hdd fails and I lose every single thing on m pc. Can RAID be ghost? If so, does that mean if I get a new hdd I can just install the ghost file to it? Does ghost compress the file? How big will the ghost be if say I want to image 320GB?

po0k

The Ghost is (afaik) as big as the data on the drive you're backing up.
If you only need ~160Gig of space and Read speed is all you're interested in (loading up maps quickly for gaming etc.) then a RAID1 array would be what I'd reccomend.
If you've got 4 SATA channels, putting your two current drives in a RAID0 array and getting another 2 indentical or larger capacity drives in the future (should cost only €220 in ~6months time) should provide you with enough speed, protection and capactity to see you through your current system's life expectancy, and into your next one (if you create a hardware array and your next mobo has the same or similar controller that is).

Otherwise, you could risk it (no more riskier really than using a single drive on it's own, and you've still got the 60Gig to backup the really important stuff) and just go RAID0 with a pair of reliable drives and ensure they're properly cooled (hdd coolers with the drives mounted in a 5.25" slot each or in 3.5" drive cages with a case fan blowing cool air over them) to ensure long life and stability.
Also, for extra paranoia, get some sort of S.M.A.R.T. monitoring software (Samurize desktop has some plugins for it, but there are plenty of others) which will at least give you a heads up if the drive(s) start(s) to develop poor performance indicating a possible failure in the near-future.