RAID: Solve This...

[Nasti]

Here's my last attempt to solve my RAID conspiracy.

Quantum Fireball Plus AS ATA100 7200RPM 30GB x 2
Sandra Mark: 32000
ATTO Screenie Here

Ok here are the facts:
*Windows 2000 SP2
*Motherboard BIOS: 64
*RAID BIOS: Whatever bios it is that comes with mobo BIOS v.64
*Windows HPT Driver: 2.0.1019
*Block Size: 16k
*UDMA Mode in RAID BIOS: 5
*Via 4in1s 4.35v
*NT File System
*ATA 100 cables
*Separate cables
*Separate channels
*Disk compression off
*?SCSI and RAID Controllers
|-HighPoint RCM Device
|-HPT370 UDMA/ATA100 Raid Controller?
Quantum Fireball Plus AS 7200RPM ATA100

What else..?
Im lost....why are they performing so poorly!

 

[tboo]

Im confused? Your scores look fine for a RAID 0 setup

 

[Budman]

IDE raid is very much hyped up. there's no real day to day feel better increase.

you have 2 nice hd's try using then in non raid.

 

[ChrisIsBored]

Budman said it... your problem lies in IDE.

Something I would never mess with for any RAID setup, but to each his own.

 

[mithrandir2001]

Performance is not much better and you've increased the chance for failure by using RAID 0 striping. I'll stick to non-RAID.

 

[Antisocial Virge]

My peak in ATTO is just over 70k compared to your 40k. I just got done installing 2 X 60 gig IBM 60 GXP. I also have a 45 gig Maxtor for backup protection.

 

[BigNeko]

I`ve seen it said a couple of times that a raid 0 setup increases chances of failure. How is the chance any greater than having a single drive running? Either case, the drive goes down you are SOL. Makes the case for raid 0+1?

 

[BigNeko]

Bump for my raid question.

 

[ChrisIsBored]

BigNeko you're correct... pretty much. Using RAID 0 is not overly dangerous. If you're running a home desktop, I would recommend it over any other setup. Unless you need the redundancy, there's no other reason to go to anything but RAID 0 really. At least for home use...

The factors that do make it kinda iffy though are the fact that you have two drives that have a possibility of failing, and/or borking your RAID card... seeing as RAID is built into your mobo.. that one less...

I wouldn't really worry about the drives dying any more than I would a single IDE drive... if you wanted performance from RAID though.. start thinking SCSI.

 

[BigNeko]

Ischrisstillbored,
If so, I read the Anandtech article about the raid cards (software driven, software driven, hardware driven). My question is, if I`m setting up raid 0+1 (example) which is faster: onboard raid controller on MB or add-on card. add-on going through PCI, does onboard controller also go through the PCI bus at some point? Seems to me onboard would be faster. But then again I really don`t know.
Any refs and I`ll quit being lazy and read.
Thnx

 

[ChrisIsBored]

That question is out of my knowledge...

I don't know much about onboard RAID, nor have I had the chance to use it. I can say though that IDE is very limited in data transfer compared to SCSI. And you're going to be taking a pretty good performance hit, especially if you want to do mirroring.

 

[zoom8112]

change the test lenth to highest, 32mb i believe

 

[Jiggz]

If so, I read the Anandtech article about the raid cards (software driven, software driven, hardware driven). My question is, if I`m setting up raid 0+1 (example) which is faster: onboard raid controller on MB or add-on card. add-on going through PCI, does onboard controller also go through the PCI bus at some point? Seems to me onboard would be faster. But then again I really don`t know.

Both the onboard IDE and the Built in RAID goes thru the PCI bus and always run on the same frequency. The reason the built in RAID is considered slower than an add on card is because it's a "lite" version. With the word itself you can tell it's a "neutered" type of RAID compare to the add on card.

As for the question of failure rate, a lot of people still thinks of the end result rather than the probability of a failure happening. If I have one ide hdd on my system and a 2 hdd RAID setup anytime one of the drive fails, either on a single hdd or 2 hdd RAID setup the system fails. This is the end result! But what is the probability of a 2 hdd RAID failing compare to a single hdd system? Twice as much. Or if the RAID is 4 hdd setup then it'll be 4 times as much. Don't be confused about the end result for it's definite that anytime a hdd fails, either on a single hdd setup or multiple hdd RAID setup the system fails; but rather think about the probability of the system failing if it has 1 or multiple hdd's.

 

[ucla88]

<< `ve seen it said a couple of times that a raid 0 setup increases chances of failure. How is the chance any greater than having a single drive running? >>



jiggz is right. while the chance of failure of any single hdd is the same, the chance of failure of the array is roughly twice as high in a two disk system.

incidentally, mirroring does not require any significant processing unlike raid 3 or 5 and works with minimal computational overhead or penalty in software raid 0 whether or not you use widows mirroring or the promise or highpoint software.

 

[Antisocial Virge]

<< while the chance of failure of any single hdd is the same, the chance of failure of the array is roughly twice as high in a two disk system. >>



So I should only run one stick of ram instead of two? Since running 2 sticks of ram doubles my chance of having a ram problem?

I think you guys need to look at this not by the numbers. Two hardrives sit on the shelf, I buy both and run raid, My raid will die when the weaker of the drives give out. You go in and buy one and just run it as a single drive, if you happen to pick up the weaker drive then your data is screwed the exact same way mine was.


Numbers don't always tell the whole story. I've been running a raid for a while now and have never had a prob. I would take the odds that my raid will survive over a single 45 gig IBM 75 GXP anyday.

 

[ucla88]

<< So I should only run one stick of ram instead of two? Since running 2 sticks of ram doubles my chance of having a ram problem? >>



well, yes, your risk of ram failure doubles. but, if one module fails, it won't necessarily bring the system down, unlike raid 0.

bad analogy.

my point remains correct.

i've got nothing against raid 0, i'm running 2 scsi 10k cheetahs that way. but i've also got the partitions set up so i have a raid 1 volume as well as backup. just in case my raid 0 volume fails (2 18gb drives split into a raid 0 18gb and raid 1 9gb volume).



<< Numbers don't always tell the whole story. I've been running a raid for a while now and have never had a prob. I would take the odds that my raid will survive over a single 45 gig IBM 75 GXP anyday >>



if you're saying that one failure prone drive is less reliable than raid 0 with good drives-that may be the case. it depends on their specific failure rates. the numbers, in this case, would tell the story.

if you're saying that a two drive ibm 75gxp setup in raid 0 is preferable to a single 75gxp.....

 

[Antisocial Virge]

<< i've got nothing against raid 0, i'm running 2 scsi 10k cheetahs that way. but i've also got the partitions set up so i have a raid 1 volume as well as backup. just in case my raid 0 volume fails (2 18gb drives split into a raid 0 18gb and raid 1 9gb volume). >>



I don't follow how you have it setup here? your running raid 1 but only with 2 drives?

 

[ucla88]

what i have is an ami megaraid series scsi card and two 10k cheetahs.
with this card you can raid multiple partions anyway you like.

i have two partitions on each 18gb drive. one partition on each is striped to give me 9+9gb=18gb in raid 0. the other two partitions are mirrored to give me a 9+9=9gb raid 1 volume. so i have two volumes, effectively, an 18gb raid 0 and a 9gb raid 1 one. now, this doesn't come without a price. if i'm accessing the raid 1 volume it will slow the raid 0 volume, because, obviously the heads can only write to one location at a time. but this isn't that important as i only place backups on my mirrored volume.

 

[Antisocial Virge]

With that setup there you still lose your data if you have a drive failure though right? Thant only protects you if your raid o goes down?

 

[ucla88]

well, no. if any single drive fails, the raid 1 array will continue to function.
yes, i lose my raid 0, but not my raid 1.

i then by a new drive. reimage the raid 0 array and i'm back in business.