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to raid or not ro raid..that is my question....and few tbird questions...

L

loosbrew

Golden Member
hey all...im new and have been reading anandtech for a while now. i just purchased an abit kt7 w/raid and a tbird 900 w/fop32 hsf. thanx to this wonderful site, i am very happy with this new hardware...but...(always!)..i do have a question about raiding my two HDD's. i have a eide 7200 rpm 15 gig maxtor as my pimary and a slower 5400 rpm samsung for my slave. i know if i raid te two that the maxtor will run at 5400 instead of 7200. so my question is, will i still get better performance out of the two raided drives running at 5400 than the left only 7200rpm drive? also..if i did raid them,would i have to reformat them both?? it was something i had heard along the way and wasnt to sure about it. btw..im just noticing how much this ubb rules!

on to the tbird/abit questions.....in my bios acpi isnt an option for me to disable or enable. i know it should be but its not there..anyone know possibly why it never showed up??
i also thought that the tbird had 256k of L1 cache..but a benchmark i did..winbench99/cpubench99 only showed 128?? 😕 ..i know that i have a tbird as i installed it myself and its running at 900mhz..butmaybe its a duron and the co jipped me?? :disgust:

thanx for all of he great reviews and honest opinions over the last few months that i have been here...

loosbrew
 
My impression of RAID is that the devices need to be matched. Certainly they must be matched in size, but I've always thought that they needed to be matched in speed as well. I'm not quite sure how to even analyze the speed of an unmatched array. You are striping, so it seems to me that, if this is even technically possible, that you will pull the stripe off the fast drive and then wait for the stripe from the slow drive. So I wouldn't think that it would matter what order the drives are set up. Yes, I believe that you'd need to reformat them.

Edit: having read a bit more, I agree with the others. The drive's sizes don't need to be matched, but the smaller will determine how much of the larger is used. So they will be matched when you are done and this may result in wasted/unused space. And throughput will be improved over the speed of the slower drive, but probably not enough to make it worth it when you consider the reduction in reliability.
 
Personally I would stay away from Raid in your situation. With either mirroring or striping, everything will be based off of the smaller drive. And you will need to format at least one of the driver if not both depending upon how you choose to raid them. Disk performance will go up but at the cost of cpu performance.
 
Actually, raided drives do not need to be the same size. The size of the raid 0 array will just be twice the size of the smallest drive. I do not know if different speed drives would work, though. Theoretically it probably would work, but I wouldn't push your luck.

If you want to try raid, you would be much better starting with 2 matched drives, especially since you have to start from scratch anyway.
 
Is the loss of all data only when the HDD actually totally fails? Will you lose all data if for instance only some of the data is written (say only half of the some data is striped and written), when the power cuts out?
 
All this about lossing one drive...bla bla...

So? What's the chance?

Here's my .02

With IDE RAID becoming Very affordable now, and the price of IDE Drives... Anyone that craves performance is crazy not to exploit this. I hear people all the time saying "SCSI if you want performance!!!!" BAH!

Price 70 gig's worth of SCSI (2-36 giggers) and a controller... about $1,000. No thanks!

If you have the motherboard with Built in RAID, you can buy 2, 30 gig hard drives (60 gigs!) for about $250 total and stripe them and DOUBLE your transfer rate! Killer performance for 5400 RPM drives for the Price! And for just a few dollars more, you can use 7200 RPM drives! You'll get a LOT more performance out of Striped 5400 drives than a single 7200RPM drive ALL DAY LONG!
 
I am not understanding raid exactally i dont think. If you stripe two 30gig 7200rpm drives do you acctually still have 60 gigs at what type of performance?
 
Since you're striping and with average priced cards, I'll just assume you're using RAID 0, which is basically just splitting up data in between the 2 hard drives you have. You aren't losing any HDD space because you're not duplicating any of the information you're storing (so no redundancy in RAID 0, but you get the use of 2x as much space as your smallest HDD). The advantage is that you are speeding up data transfer since you're using the transfer speed of 2 hard drives at the same time instead of one at a time (ie. you store the entire file on one drive).

Take a quick look here: http://www.raid5.com/raid.html for some information on the various levels of RAID. It basically outlines the advantages and disadvantages of each RAID level.

A bit more in-depth explanation of RAID can be found here: http://www.dell.com/us/en/biz/topics/vectors_1999-raid.htm

In short: if you use RAID 0 - you get the full capacity of your two 30GB drives = 60GB total

If you use another common RAID level RAID 1 (it does mirroring but no striping) then you only have the capacity of the smallest drive 2x 30GB drives = 30GB total space.
 
ok so if i raided my two existing HDD's, i would get a total of 21 gigs(15+6) and they both would run at 10800 rpm?? not sure if im wrong about it...
thanx for all of the replies..

loosbrew
 
nono your rpm won`t change however you`re transfer rater for the individual drives will fall back for both of them to the lowest of the two.

If I understand it correctly that is.
 


<< DOUBLE your transfer rate! >>



This is not true, your transfer rate will go up 50-75% (if you have one disk and add another, if you are adding a third, the increase will be around 15-25%) compared to the slowest drive in the system.

Then there is one more thing to consider, the IDE RAID is just software, so you will be using your CPU power for the RAID.

However, the problem with data loss is a chance you might not want to take, considering you are using an older drive, and if you get bad sectors, all of your data might be lost.

The L1 cache of the T-bird is 128KB, the 256KB you are thinking about is the L2 cache.

Patrick Palm

Am speaking for PC Resources
 
From what I've read around the forums, IDE RAID devices like the Promise Controllers and the Highpoint Controller are still software driven, so they're still Software RAID. Unless there are new cards that have come out? (that don't cost a grand 🙁 ) If there are I'm interested to know 🙂
 
I personally would not go with raid because if one thing gets messed up it is all messed!...that is all that I know about raid.

Guru
 
No you should not RAID

First off, IDE RAID is all software based so it uses a heavy amount of CPU time to calculate where the stripes should go...that's a general gripe, but if you have a 900Mhz CPU you might not notice this...

Specifically for you RAID is a bad idea because:
RAID0 worsens average seek time, BOTH drives have to seek to the track you want, so the nice speedy seek time on your 7200rpm gets kicked back down to the speed of the 5400rpm...ouch...

Your 15 gig gets cut down to size, you do not get 15+6 gigs, you get the smaller drive x 2, so you get 12 gigs total. Yay

And yes while you will have improved transfer rate using the RAID0 you will have much worse seek time than your 7200rpm alone, and you will have CPU overhead as well. If you want to have a powerful RAID setup, get a 2nd 15gig 7200rpm, then you can have roughly the seek time of a 7200rpm (it's actually slightly worse average, but it's close), and 14,400rpm transfer rate equivilant, (Edit: note this a theoretical number, in practice 2way RAID0 is not a perfect doubling, more like 150-175% of a single drive's transfer rate) and you can have a 30gig drive.

IDE RAID has it's plusses and minuses...in your case there are alot of minuses...and the only plus is bumping up transfer rate from 7200rpm to 2x5400rpm, which in practice probably ins't even an imporvement, RAID0 is a perfect doubling...you lose size, seek time, CPU time....
I would not do it if I were you.


Depending on what you do with your system RAID0 might be absolutely useless to you anyways...if you are a gamer and you have enough RAM to avoid disk thrashing all you'll get from the deal is the CPU overheard...the game will load a bit faster, but it won't run faster...

If you are doing A/V editing or something then RAID0 is a good idea because disk speed is a big limitation in that sort of work, much more so than the CPU time you lose.

(Note: This is a general guideline for RAID0, in your case it's a bad idea anyway you look at it)


I don't know anything about the KT7 or your ACPI question...but if your CPU is has 128k L2 cache then it's a bum TBird...Durons don't have 128k, they only have 64k L2. TBird's have 256k L2...so either side of the fence you shouldn't be showing 128k L2...the only x86 chip that has 128k L2 is the Celerons (maybe something from Via...I'm not sure what their chips have...but that's worse than a celeron)

But a Celeron wouldn't fit in a KT7, so it's likely a bum TBird...
or maybe that program is inaccurate.
 


<< Uhmmm, there are IDE Raid devices now PCResources dude... so it's Hardware raided... >>



It works just like those riser modems and sound cards, the card is only a connector, the actual job is done in software.

I see some of you writing that only the &quot;cheap IDE RAID controllers&quot; are software based.

I might be wrong here, but i have never seen any IDE RAID controllers that are not software based, so if you have any info on this please respond to this thread, a link would help a lot, thanx.

Patrick Palm

Am speaking for PC Resources
 
oooooh adaptec has hardware IDE RAID now...spiffy 😉
Well that might be cool to have with a pair of 7200rpm drives, I'd still rcommend against it for you loosebrew (see my post above all the reasons but CPU usage remain), but HW IDE RAID with two similar drives could be very cool.
Oh sweet love of SIN! That adaptec card has RAID5! For IDE drives. I'm liking this...
 
I could be wrong but I think the 3ware Escalade 6000 series is hardware raid. (Or a combo harware/software) The site says it has an on board processor to reduce cpu overhead. I found one of these for $135. And people over at storage review say its much better than a hp or promise. They even have an 8 port version.

I actually just made a post on this and was wondering if anybody has used one of these.

As far as worring about loosing data if 1 of 2 drives goes down is silly. The chances are nill. That's like worrying about loosing data if you only have 1 drive and it goes down. (Back up your stuff either way)

Recent upgrades to controllers have proven that seek times are not affected. (Using same drives)

CPU utilization should not be a concern. So what if it jumps to 20-25%, or 50% for that matter. If your cpu needs information from your hd, and can't do anything else until it gets that info, who cares how much your cpu is being used. It has nothing else to do but wait. Once the cpu has the info it needs, the cpu utilization drops back down because it is no longer accessing the hd. There is rarely a time when hd cpu utilization and a program cpu utilization will in fact slow your system down if you are using a fast processor and a good amout of memory.

3ware Escalade 6000 series
 
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