RAID setup, some questions

[BIGgui_X_]

I'll receive my dual 1.25 in a couples of days ! Since i have a couple of 40 gig 7200 rpm drives left, i wonder if it would be a good idea to put them inside the G4 and use the osX raid setup for those 2 drive (for the Osx system disk). Is it a good idea or is it a wate of time and HDD space ? I would really like to optimize every part of my dual 1.25 (overclock it to 1.33, I'll max the RAM, i'll buy a 9800 later, etc). I'm not very familiar with raid thing, anyone have a good website or informations for me ? If i buy a PCI card for internal raid setup, really faster than softraid ? how could i take advantage of this the most (system disk, apps disk, games, etc ? )

thanks alot !

 

[Veldek]

I'm interested in this, too.

 

[VegetaPunk]

someone correct me if im wrong...because I would like to know if there is any other big advantages to having a raid setup.....

I think the big + to having a raid setup is that you will always have a back up of your information, so if one of the raid hard drives dies while you are using you computer it just will still work and you wont loose any of your data.

 

[BIGgui_X_]

i know there is a mirroring mode, but, i dont want to backup my data !
i think that there is another mode, like plitting the data between the 2 HD, to reduce the time of the copy, etc !!

so, still waiting for some advice, thanks !

 

[VegetaPunk]

I think what you want is called stripe mode, im sorry im am not helping that much but I am not familar with this.... I will post again when I have more info

 

[VegetaPunk]

Q: What does the RAID 0 "Striping" feature do?_
A: RAID 0 (Striping) configures multiple drives so that sectors of data are interleaved within an array. When a disk member fails, it affect the entire array. Performance is better than a single drive since the workload is balanced between array members. This array mode is designed for high performance systems. Identical drives are recommended for performance as well as data storage efficiency. The disk array data capacity is equal to the number of drive members times the smallest member capacity.

Q: What does the RAID 1 "Mirroring" feature do?
A: RAID 1 (Mirroring) configures an array of 2 drives to write duplicate data and read in parallel. The HPT370 performs reads using advanced data handling techniques that distribute the workload in a more efficient manner than using a single drive. When a read request is made, the HPT 370 selects the drive positioned closest to the requested data, then looks to the idle drive to perform the next read access.

Q: What does the RAID 0+1 "Striping + Mirroring" feature do?_
A: RAID 0+1 (Striping + Mirroring) is a combination of both striping and mirroring. It can increase performance by reading and writing data in parallel while protecting data with duplication. A minimum of three drives, two of which are in a stripe array, are needed to enable this feature. This feature allows for mirroring two stripe arrays together or one stripe array with a single disk. The data capacity is similar to a standard Mirroring array with half of total capacity dedicated for redundancy.

 

[BIGgui_X_]

ok !!

But, is it usefull for everyday life, app launching, osX system disk, games, etc etc ? or is it only usefull in heavy task like video editing, etc ?

thanks

 

[revenuee]

Re: ok !!

Originally posted by BIGgui_X_
But, is it usefull for everyday life, app launching, osX system disk, games, etc etc ? or is it only usefull in heavy task like video editing, etc ?

thanks

After seeing your post this morning i got interested myself. This is what i found;

Unless you want to have a constant back up of your saved games, installed apps, or system disk, then the RAID won't be an advantage.

If you don't need all the drives to act as a single volume, you won't see any advantages either.

You should still be able to install those drives into your computer and have the benifits of several drives and lots of disk space. ie 4 seperate volumes.

But as far as speeding up app launching, faster OS, faster gaming - i didn't find anything prooving that it would

 

[acj]

RAID 0, 3, 0+1, and 5 speed things up.

RAID 1, 3, 0+1, and 5 provide redundancy. One drive fails, data is still there.

Notice the overlap. RAID 5 is the most popular for "best of both worlds" because you get all but one of the drives data. So with 3, 10GB drives you get 20GB available space.

I built a computer that has 4 250GB drives in a raid 5 setup. 750GB are available. If any one drive fails, absolutely no data is lost.

For your purpose, RAID 0 will speed things up, but if ONE drive fails, ALL your data is lost on BOTH drives.

 

[BIGgui_X_]

Ok !
So If this security backup is not important to me (bakuping often on DVD) I can buy a raid card for RAID 0 (because i assume that osX raid is slow compared to a raid card) and use my 2 40 gig drive, so there will be only 40 gig of space, but the data will be like splitted between the 2 drives ? Ok.. so, if anyone can confirm that it's speeding thinks up for everyday life, i'll do it ! Do i need exactly 2 identical drives ? 2x 40 gig of different brand, even if they are 7200 rpm, etc, cant be use i suppose ?

thansk alors, that really helps !

 

[VegetaPunk]

they can be different dives.

I have heard read that the OS X RAID software isnt that great, so your right to buy the card...

as for speeding things up for everyday life I dont know... sorry

 

[daveL]

Originally posted by acj
RAID 0, 3, 0+1, and 5 speed things up.

RAID 1, 3, 0+1, and 5 provide redundancy. One drive fails, data is still there.

Notice the overlap. RAID 5 is the most popular for "best of both worlds" because you get all but one of the drives data. So with 3, 10GB drives you get 20GB available space.

I built a computer that has 4 250GB drives in a raid 5 setup. 750GB are available. If any one drive fails, absolutely no data is lost.

For your purpose, RAID 0 will speed things up, but if ONE drive fails, ALL your data is lost on BOTH drives.

Well ... RAID 3 and 5 suck for write intensive applications. These RAID modes also suck for software (host-based) implementations due to the compute overhead of calculating the new parity value *everytime* you write to *any disk*. The performance gain you mention is only there for read operations.

RAID 0 will always give you the best read/write performance. RAID 1+0 will give you the best read/write performance AND the best redundancy. The main advantage to RAID 3 and 5 is cost, since they require fewer drives to give you redundancy. Oh, and when you lose a drive on a RAID 3 or RAID 5 volume, when you replace it, it takes a long time to sync it up, during which you're performance suffers.

 

[acj]

Originally posted by daveL
Well ... RAID 3 and 5 suck for write intensive applications. These RAID modes also suck for software (host-based) implementations due to the compute overhead of calculating the new parity value *everytime* you write to *any disk*. The performance gain you mention is only there for read operations.

RAID 0 will always give you the best read/write performance. RAID 1+0 will give you the best read/write performance AND the best redundancy. The main advantage to RAID 3 and 5 is cost, since they require fewer drives to give you redundancy. Oh, and when you lose a drive on a RAID 3 or RAID 5 volume, when you replace it, it takes a long time to sync it up, during which you're performance suffers.

Good clarification. A good RAID card will calculate parity quickly though and still give performance increase over a single drive. It will also rebuild automatically in the background. According to a source I looked at, RAID 5 takes a performance hit if one drive fails, RAID 3 does not, but both do during rebuild. RAID 3 and 5 are really great when you have a lot of drives. With 10 drives you get 90% of your space, while with RAID 0+1 you get 50%.