RAID question...... - Tilted Forum Project Discussion Community

scavengertype · 10-23-2003, 06:14 AM

I currently have a RAID-ready mobo (ASUS A7V333) with a single WD Caviar 80GB 8MB cache 7200 drive. I am planning on getting another drive fairly soon, but I recently read that setting up a RAID array is a good way to boost performance.
If I get another identical drive and set them up in a RAID array, I understand that it will be recognized as a single 160GB drive. Will I still have the advantage of the caches, as in a 16MB cache? Can anyone offer any advice or point me to any tutorials or anything about doing this, risks involved, performance, etc.?

oberon · 10-23-2003, 06:33 AM

When you say RAID, you need to specify the RAID type. Since you have an 80GB drive currently and are planning on only getting one more, I assume you mean RAID 0, which is striping.

The primary disadvantage of such a configuration is the loss in reliability. That is, if one drive fails, you lose both. Performance will probably not be MUCH better than if the drives were alone (and being used at the same time), but that depends mostly on the solution used to implement it. That is, performance won't improve by 100%, it will be more marked, probably more like 50% or less.

The caches are not combined; they are still specific to the drive they belong to.

So, in short, there are some pitfalls. But if you backup your data anyway, then why not?

Pragma · 10-23-2003, 12:32 PM

Here's a Quick Explanation of RAID for you while you're at it.

The individual drives will still have an 8MB read cache, plus they'll benefit from the RAID0 striping (which is I think what you were asking).

keef · 10-23-2003, 02:00 PM

I have a promise RAID controller, and have had no problems (why did i just say that) with it thus far.

The speed boost is definatly noticeable; being able to copy files while listening to mp3s and surfing is very tolerable with raid 0.

with 2 channels i have 2 partitions; i can use winimage and rebuild win98 in 4:30 mins

your best bet is to stick with an identical drive.

Vanquish · 10-24-2003, 03:46 PM

Yeah the speed is a HUGE plus, the way it works is that each file is writen across each drive in the same ammount. The problem with doing it this way is 2 fold as most have already said, the stability is not good, but if your only running home apps you risk a HDD Crash anyway, second if your dealing with MANY small files, your drive will still use the same amount of space with a 1kb file as it will with a bigger (around 64k mostly) file. You can change this size with most RAID controlers, but some you cannot. On the plus side tho, My 4 way RAID 0 WDSE100JB drives were performing around 3x the speed of a 15000RPM pro SCSI drive. That makes moving things around, and just the basic use of the drive SUPER easy. Also if your into DV editing you will really love how the drives give you that extra boost when recording things.

I wouldn't recomend using it as a primary drive tho (as in a Boot partition) because everytime you go to wipe your system you will need to boot the RAID Drivers along with your CD Rom, its not THAT hard, but it is an annoyance.

steveincolumbus · 10-25-2003, 12:44 PM

the bad point of raid 0 is when you double the number of drives (1 drive to 2) you also double the amount of failers possible do to hard drive failer and now have to recover all of that data that you lost do to no redundancy, I would prefer raid 5, or at least have a good way to backup important data....

tekaweni · 10-25-2003, 01:20 PM

So in summary, raid 0 = take lots of backups and enjoy ~70% performance increase. Your risk of hardware failure is doubled assuming 2 disks - ohhh right, you can add even more......

And yes, the benefit is incremental. I run 4 striped disks. Sub-10second boot for win2k on an xp1800 cpu system, but I accept the 4x failure risk. When you lose one striped drive, you lose 'em all

Same as a Ferarri, thats the price of the fast lane.

scavengertype · 10-27-2003, 09:16 AM

If a drive fails, assumming the data is recoverable, could you copy the data to a new identical drive and replace the failed drive?

10-23-2003, 06:14 AM	#1 (permalink)
scavengertype Tilted	RAID question...... I currently have a RAID-ready mobo (ASUS A7V333) with a single WD Caviar 80GB 8MB cache 7200 drive. I am planning on getting another drive fairly soon, but I recently read that setting up a RAID array is a good way to boost performance. If I get another identical drive and set them up in a RAID array, I understand that it will be recognized as a single 160GB drive. Will I still have the advantage of the caches, as in a 16MB cache? Can anyone offer any advice or point me to any tutorials or anything about doing this, risks involved, performance, etc.?

10-23-2003, 06:33 AM	#2 (permalink)
oberon Quadrature Amplitude Modulator Location: Denver	When you say RAID, you need to specify the RAID type. Since you have an 80GB drive currently and are planning on only getting one more, I assume you mean RAID 0, which is striping. The primary disadvantage of such a configuration is the loss in reliability. That is, if one drive fails, you lose both. Performance will probably not be MUCH better than if the drives were alone (and being used at the same time), but that depends mostly on the solution used to implement it. That is, performance won't improve by 100%, it will be more marked, probably more like 50% or less. The caches are not combined; they are still specific to the drive they belong to. So, in short, there are some pitfalls. But if you backup your data anyway, then why not? __________________ "There are finer fish in the sea than have ever been caught." -- Irish proverb

10-23-2003, 12:32 PM	#3 (permalink)
Pragma I am Winter Born Location: Alexandria, VA	Here's a Quick Explanation of RAID for you while you're at it. The individual drives will still have an 8MB read cache, plus they'll benefit from the RAID0 striping (which is I think what you were asking). __________________ Eat antimatter, Posleen-boy!

10-25-2003, 01:20 PM	#7 (permalink)
tekaweni It wasnt me Location: Scotland	So in summary, raid 0 = take lots of backups and enjoy ~70% performance increase. Your risk of hardware failure is doubled assuming 2 disks - ohhh right, you can add even more...... And yes, the benefit is incremental. I run 4 striped disks. Sub-10second boot for win2k on an xp1800 cpu system, but I accept the 4x failure risk. When you lose one striped drive, you lose 'em all Same as a Ferarri, thats the price of the fast lane. __________________ If you always do what you've always done, you'll always get what you've always gotten

10-23-2003, 02:00 PM	#4 (permalink)
keef Tilted Location: south east US	I have a promise RAID controller, and have had no problems (why did i just say that) with it thus far. The speed boost is definatly noticeable; being able to copy files while listening to mp3s and surfing is very tolerable with raid 0. with 2 channels i have 2 partitions; i can use winimage and rebuild win98 in 4:30 mins your best bet is to stick with an identical drive.

10-24-2003, 03:46 PM	#5 (permalink)
Vanquish Insane Location: Truro, Nova Scotia	Yeah the speed is a HUGE plus, the way it works is that each file is writen across each drive in the same ammount. The problem with doing it this way is 2 fold as most have already said, the stability is not good, but if your only running home apps you risk a HDD Crash anyway, second if your dealing with MANY small files, your drive will still use the same amount of space with a 1kb file as it will with a bigger (around 64k mostly) file. You can change this size with most RAID controlers, but some you cannot. On the plus side tho, My 4 way RAID 0 WDSE100JB drives were performing around 3x the speed of a 15000RPM pro SCSI drive. That makes moving things around, and just the basic use of the drive SUPER easy. Also if your into DV editing you will really love how the drives give you that extra boost when recording things. I wouldn't recomend using it as a primary drive tho (as in a Boot partition) because everytime you go to wipe your system you will need to boot the RAID Drivers along with your CD Rom, its not THAT hard, but it is an annoyance.

10-25-2003, 12:44 PM	#6 (permalink)
steveincolumbus Psycho Location: BFE, Kentucky	the bad point of raid 0 is when you double the number of drives (1 drive to 2) you also double the amount of failers possible do to hard drive failer and now have to recover all of that data that you lost do to no redundancy, I would prefer raid 5, or at least have a good way to backup important data....

10-27-2003, 09:16 AM	#8 (permalink)
scavengertype Tilted	If a drive fails, assumming the data is recoverable, could you copy the data to a new identical drive and replace the failed drive?