SATA-II explained

[smids]

Hi, Welcome to the forums ,

Right, onto business - basically there will be no difference between the two. Bust will be higher on a 300MB/s enabled SATA2 drive but for drives like Seagates, seeing as all have had NCQ since the 7200.7, there is will be no difference between a SATA1 and SATA-II drive. SATA-II drives *might* have 1-2MB/s higher average read due to higher bursts which raise the average but that is about it. Still, I advise to get a SATA-II drive as they do have more features often.

I would agree with you, that a 16MB cache is probably more beneficial for a single drive user than an 8MB and would suggest this as your drive. I would have a look at the Seagate 7200.9 250GB 16MB cache drive - this seems like a good bet - SATA-II, 3.0gbp/s, NCQ (one of the best command queuing chips of all manufacturers), 16MB cache.

Also, on a cost per GB ratio, I believe 200GB upwards is the way to go now.

 

[smids]

Can I mix a SATA-II drive with an older SATA drive to create a RAID 0 volume? My mobo-controller only supports the original standard and I've bought an updated SATA-II version of the drive that I already have (a 160gb Maxtor).

Also, would this destroy the contents of the original drive? Would Windows XP (being the evil pig-dog that it is) require reinstallation anyway?

TIA!

You can so long as you limit force 150MB/s external if the SATA-II is a 300MB/s drive. Creating any RAID0 will destroy all data and require a reinstallation.

 

[smids]

Bum, I was afraid of that... will it make much of a difference for gaming? (BF2 primarily).

Thanks for your advice smids

Only in map loading. Yes it would be faster, but just for map loading - so the question is, is it worth it?

Also, despite them being 'able' to RAID0, I seriously advie the use of 2 identical disks. RAID0 is prone enough as it is with two identical drives to failure but with completely different generation drives, the chance of say data corruption etc is greater or possible other issues. The controller will see them as just 2 xxxGB capacity drives but there will be differences in times to read or write between them.

 

[smids]

Thanks smids!!! top quality info there! Then thats the one i shall get. Just one other thing, other than a hard drive im good to go, is it possible to turn the PC on without a harddrive installed, just to check everything is working? and to take a peek at the bios?

Obviously i dont want to damage anything! lol

Yes, you can turn you PC on without a HD and go into BIOS .

 

[smids]

Thanks for the sticky, that has cleared up many questions I wanted to ask!

Heh, no problems - if you have any questions not covered, please ask in here and if in general interest, will be added to the sticky .

 

[smids]

I'm a bit confused, will standard SATA cables support the full SATA2 Speed if you have them set up in raid, I was under the impression that you need SATA 2 cables, which can handle that amount of speed, like the Silverstone SATA 2 cables...

http://www.silverstonetek.com/products-cp01.htm

Marketing nonsense - a SATA cable will provide full speed - 150 or 300MB/s.

 

[smids]

yes but thats what happened with USB 1 and USB 2.0 cables, USB 1.0 cables could not handle the bandwidth of usb 2.0 speeds.., is it not the same wiht SATA cables?..

Nope - SATA cables are just simply that. I'm sure there is a maximum bandwidth somewhere, but for now, it copes easily.

 

[smids]

I can see your understanding of the various RAID levels is flawed .

http://www.acnc.com/04_01_00.html for more info. Use the bar at the top to look at various RAID levels.

In short: you are looking at RAID0, RAID1 and RAID1+0 (let's stick to RAID 0+1 for now, RAID 1+0 is also known as RAID 10 and is a bit more complex).

RAID0 - 2 drives minimum, 1/2 data on each drive therefore almost doubling reads (will never actually be double, more like 150-160% of one drive speed) and writes because more data can be read and written at the same time. Very unreliable - one drive fails, the array fails = all data lost. Total space sum of all drive capacities.

RAID1 - 2 drives minimum. Data is written to 2 drives. Excellent reliability - if one drive fails, you automatically run from the good drive and then the array may be rebuilt when the duff drive is RMA'ed etc. High cost as 2 drives = 1 drive storage space. I.e. drive storage = total drive capacities divided by 2.

RAID0+1 - 4 drives minimum required. A RAID0 array which is mirrored. i.e like 2 parallel RAID0 arrays. Can survive one drive failure without loss of data and 2 drives if one array completely fails i.e. you are left with one RAID0 array still running. Drive capacity = total drive capacity divided by 2. Benefits of RAID0 speed with RAID1 reliability but high cost of 4 drives.

RAID1 is useful for data backup BUT if one drive corrupts, i.e. virus, this is mirrored to the second drive! Yes, not a great thing to happen.

If you have a normal backup drive i.e. XP+ data drive (HDU1) where the data is backed up to HDU2, HDU2 will function with any installation of new OS's etc. It is an independent disk entirely (don't format it obviously when installing on the other HDU! ). So in answer to your question, yes it will still be read.

Porting a current installation is possible. I would use something like Acronis True Image 9 Home which is what I use - it is excellent and much more reliable than something like Norton Ghost 10 or 9 when dealing with RAID arrays.

Hope this helps - let me know if you have any more questions.

 

[smids]

Reliability is entirely the reliability of the individual drives. If a drive fails, it fails, nothing can be done. All you have to consider is probability.

1 drive, chance of failure = 1
2 drives, chance is doubled - 2 drives same time
etc. As you can see, the chance of a disk failing increases with more drives. Simplistic, I know but it does hold true relatively.

Ripping mp3's - entirely processor dependent.
Loading game maps/unraring files, raring files, installing things, loading windows, running large apps, loading games will all be faster on a RAID0.

RAID 1 increases read by about 5%, but writes will be approximately halved as the controller has to make sure data is exact on both drives. Writes - installing things, unraring, writing video files e.g. directly recording from a DV camera. Writes are less important really.

You would only see a realistic increase with RAID0 but unless you have a good backup solution, it's not a great idea.

My setup:

RAID0 2x 80GB hitachi SATA-II - Windows/Games/Programs
RAID1 2x 80GB Hitachi SATA-II - Irreplaceable data - music , pictures, documents, backup of the entire RAID0 every week (Acronis compresses data so it can fit on this drive - uses about 30GB roughly on a normal usage RAID0 array with some games installed including Steam).
320GB Storage drive - storage but can be replaced - annoying to lose but I wouldn't lose sleep over it. Video files, data I don't care about etc (though these are put onto a DVD if I want to keep them for sure)

 

[smids]

Ok, that makes sense, thanks. Sorry, when I said ripping mp3's, I meant the time to read and write the files to disk - but thinking about it, it makes little odds because (as you say), it's relying on the cpu to process it, which the HDD should easily keep up with. Penny. Dropped.

I like the way you've got your drives set up. Very logical and sensible. So if I was to purcahse 4 x 80Gb SATAII drives, I could arrange the same arrays as you have there - one for performance, one for security and one for non-essential mass storage. Would I be right in saying that I could use my current 160Gb IDE drive as the storage drive alongside the SATAII drives (arrayed).

So if one of your SATA drives with Windows on failed, what would be involved in getting your system running again? And would that drive(s) then need to be RMA'd?

Oh, just literally copying? That would be 160% faster because of the RAID0. All read and writes on a RAID0 are faster - any encoding would limit ripping which is what I thought you meant . Writing and reading from a disk uses very little CPU and the CPU is ridiculously faster than an HDU at processing data. Think 20GB/s bandwidth of the L1 cache and about 6GB/s L2 cache (as this is what would be used for the processing of data numbers) compared with about 60MB/s for an HDU. It's the HDU that slows everything down!

My array seems logical - to the untrained eye - but is quite illogical! Watch this:

One RAID1 drive fails - easy, replace.
One RAID0 fails - not so easy. Either don't use the computer and use my laptop (like now - comp is being completely rebuilt with new mobo/RAM/PSU/improved watercooling) OR, more likely, cause a failure of the RAID1 - i.e. steal a drive and then restore the RAID0. The new drive would then slot into the RAID1 which could be rebuilt at a later date. If the other RAID1 drive failed in between and I lost everything, well then it's my fault!

 

[smids]

So if the array with the OS failed (RAID 0), you can nick one of the essential data drives (RAID 1) and slot it into the RAID 0 array. Rebuild the drive and off you go, without the RAID 1 being accessible until you've had a new drive delivered and can replace and rebuild it - (with the obvious issue of the remaining RAID 1 disk failing in the meantime and losing all your essential stuff still a possibility).

But you're saying if the RAID 0 fails, there's a high likelihood that it could kill the RAID 1 array aswell? Why is that? Surely it shouldn't affect the RAID 1 array - it's just a fault with the RAID 0 and a seperate array/disk? So in theory then, the failure of the RAID 0 would negate the benefit of the security of the RAID 1 if it increases the chance of the RAID 1 array also failing when the RAID 0 one does. Surely that's a really silly way of doing it......oh! Ah, I think I see what the problem with your setup is now!

So the only safe way to do it is to use RAID 0+1 and have all your OS/Programs/Games & esssential data kept together on the one fast Raid 0 array and mirrored using RAID 1, or by having both arrays set to RAID 1 - which would be slow and painful, but safer. Am I right in saying that both these methods give you a total of 160Gb storage space (assuming 4 x 80Gb drives are used)?

So why don't you have everything on the one 160Gb RAID 0+1? Surely it provides the same storage, but with better performance and security overall?

Would the RAID 0+1 still provide better performance than just using the SATAII drives independently (i.e. not in RAID array)?

My last question - and this doesn't necessarily relate to RAID arrays - if you use 2 x SATA(or II) drives and perform two tasks, with each task involving data from one drive (i.e. mp3 playing from one drive and video clip playing from the other), would it perform this task more efficiently than if all the data was stored on the one physical drive?

I know I've asked a lot and thanks very much for the help. Basically trying to decide whether RAID arrays are the way forward for me. Bet you wish you'd never replied now!!

Not quite - I steal a drive from my RAID1 meaning the RAID1 is now degraded but fully functioning. RAID1 can continue to be used even with a failed drive so it reduces the RAID1 to a normal disk. This becomes a RAID1 again as soon as a new disk arrives. This would be about 7 days of unsecured data. Of course, I don't have to do that, I could just use my laptop but I'm impatient. I very much doubt 2 drives would fail at the same time - the probability is extremely low hence the reason I feel happy about doing that. The two arrays are independent but the way I have it setup makes their paths cross.

I used to have a RAID0+1 but I wanted faster writes - RAID0+1 means writes are no faster than a single drive - RAID0 makes it 160%, then RAID1 virtually halves this so net it doesn't gain any write speed and may lose a tiny amount. Plus a RAID1 is ever so slightly more secure than a RAID0+1 - we're talking minute percentages here...

160GB = 4x80 RAID0+1 and yes it is better performing than independent disks.

160% reads (actually it's more like 175-180% thinking about it!)
100% writes relative to a single drive.
100% more reliable
But also louder - 4 drives seeking and working at the same time .

Last question: yes, two drives independently being accessed is more efficient and faster.

 

[smids]

Ok, thanks. That makes sense. Not as bad as I thought then. But does the failing RAID 0 array increase the likelihood of the RAID 1 array failing as well - or have I misunderstood that part?

No rush for tonight as I'm off to bed, but tomorrow would be good if you have time. Cheers mate and good night!

No, the RAID0 is completely independent of the RAID1. It's only because I take one of the RAID1 drives that it is more likely to fail - but this is not because I have taken a drive, it is because drives can fail at any time, so there is no more likelyhood of the remaining RAID1 drive failing as there was before I stole the 2nd drive. I hope that isn't too long for this hour ! I could leave the RAID1 alone and it remains completely unaffected by the RAID0 failure. It's not as bad as you think. I've never actually had an HDU failure as yet, so it's all theory for me. Considering I have 5 HDU's in total, this is good going.

 

[smids]

Yep, you understand my array now - guess you were a bit tired .

With your suggested setup - windows wouldn't run any differently from a single hard drive, only with half speed writes and about 5% increased read. Shutting down wouldn't take long. Really, it takes a lot to saturate 30mb/s writes. You probably won't even notice it until you, say, install something. Writing something to disk is quick anyway, and really only noticable if you do video editing where you need the speed and those types of application.

Can't see any downdsides reallyto your suggested setup. You might want to put essential programs on the windows drive so that if the RAID0 does go down, you can still perform essential tasks so things like Firefox/MS Office/ CD writing software all should really be with windows and non-essential programs like..umm...Divx or Realplayer could be on the RAID0.

About my setup - yes, using the backup image on my RAID1, I could just run a single drive yes - I hadn't thought of that! To quote Family Guy Episode 'Petarded': http://www.youtube.com/watch?v=7c53N0LK_es You are 'Peter' the fat guy who is the main character (green trousers, white shirt) - I am the doctor at the instutute. Watch the clip up to 00:45 seconds - yes, that's how I feel at the moment (the doctor's reaction).

 

[smids]

@Fatfish: Sorry for the lack of response to your question! You edited your post so I didn't get any notification! . Some motherboards out for the Core2 Duo range are really in their infancy and so you can expect them to be buggy. BIOS releases should fix this. The Intel chipset boards use the Intel SATA controller which is on the chipset and so you can expect certain issues until a mature BIOS is out. When the Intel SATA controller works, it's a very good controller and better than most third party onboard controllers. Only dedicated cards can beat it really.

@Dave: Yes, the hard drive will work. Make sure you set it for backwards compatibility though i.e. set 150MB/s transfer rate. For hitachi's: they are defaulted to 150MB/s in firmware - no changes required. Seagate: comes with a jumper on the hard drive which is set to 150MB/s (the 7200.10's). Maxtor and WD - not sure on these but I believe they are jumper settings, in which case just make sure that the drive is correctly set to 150MB/s before installing. .

 

[smids]

I didn't. I installed windows before making the switch and it made no difference whatsoever to the data on my disk. It's only an external transfer rate change, and not something which changes the way things are written/read from the disk.

 

[smids]

Only SATA 3.0Gbp/s needs enabling - everything else is already running .

 

[smids]

Ok, it arrived. I set it to SATA 3GB mode and disabled "spread spectrum clocking". What exactly is this? Is it better if it's enabled or not?

Don't worry about spread spectrum - it's to do with interference (radio/EM etc) just ignore it and leave it disabled.

 

[smids]

I have a 939SLI-eSATA2 which of course has SATA II. Can you tell me if it supports NCQ?

http://www.uli.com.tw/eng/products/product_detail.php?pserno=92

It would seem so if you use the ULi ports.

 

[smids]

Thanks . As I said in the first post, please add questions/comments for amendment etc.

 

[smids]

Really good post, answered most of my questions except 1:

You're basically saying there's no performace difference at all between sata 1 and sata 2. I'm looking at the tasty £30 dfi on ocuk this week only and was wondering:

Will I notice any performance hit running my shiny new 320gb 7200.10 sata2 hd in sata1 mode on the mobo (it only suppourts sata1) ?

Cheers.

No - the only [minor] performance hit will be from the 150MB/s burst. This is the cached read from the HDU buffer, it can 'only' go at 150MB/s rather than 300MB/s (actually figures are usually about 150MB/s for sata1 and 260Mb/s for sata-II). Not exactly much of a difference. Certainly it would not show in ANY real world situation.