View Full Version : Help with basics

06-16-2001, 02:45 PM
I would like to install two Seagate 9.1GB ST39102LW drives and a 45GB Maxtor ATA into a PTP 225, something that I have talked about previously over on the PCC list.

Using one Miles2 INI-A100U2W MAC and a Sonnet Tempo ATA PCI, will I be able to (and will it make sense) employ the two Seagates as a single, striped 9.1GB boot volume, and use the Maxtor as a general-purpose respository for work files, etc.?

06-16-2001, 03:04 PM
Yes. Stripe the two Seagates on the Miles U2W bus if they are the same size and model and run the Maxtor off the bus hosted by the Sonnet card.

[This message has been edited by Louie (edited 16 June 2001).]

06-16-2001, 04:43 PM
If you stripe those two Seagates in one volume, it will give you 18GB, or there abouts. k

06-18-2001, 11:59 AM
I'm a little confused. When you set up a RAID, are you making one large volume out of two smaller drives that goes faster, or can you take two drives of the same size and set them up in a way to make one the same size that's much faster? What would give me the best performance from these two drives?

06-18-2001, 12:20 PM
Well, a RAID has many classes. Check this (http://arstechnica.com/paedia/r/raid-1.html) out.

A RAID-0 would be your fastes bet. It creates one volume as large as all the drives being used in it. Ex-2 9GB drives in a RAID-0 would make a 17GB volume that mounts as one item on your desktop and acts as on. The benefit to this is you have 2 drives accessing sequential data across 2 drives.

Think of it like this....
1) You have one person copying words from a blackboard. This is a simple volume. It takes a long time to copy all the info.

2) You have 2 people both copying the same text from the blackboard. This is a mirrored RAID. Exact duplicates of the data on each independent drive. One mirrored volume....2 drives. It actually takes a little longer to copy all the data than just one drive, because or mechanical overhead of the drives and storage subsystem.

3) You have 2 people each writing every other word from the black board. That is a Striped RAID (RAID-0). It completes the read/write tasks a lot faster than a simple volume. Not quite twice as fast due to overhead...but you get the point. The first person copies down the 1st, 3rd (and so on) words and the second person copies down the 2nd (and so on). When looked at altogether, it is all there. The downside is dependability. You now have 2 drives storing one volume...twice the chance of drive failure and data loss.

That is the bare-bones basics. The article reqally does a decent job breaking it down.

06-18-2001, 12:35 PM
Striping a configuration of drives into a RAID 0 configuration allowing the user to create one large single volume. In this situation the drives set up in a RAID 0 config. act as one hard drive allowing the data transfered to the whole volume to be written and read much faster. In your situation striping two 9.1GB Cheetahs in a RAID 0 config. would leave you with one 18GB volume that acts faster than the two seperate drives.

There is also an option that offers more security called RAID 1. Striping two 9.1 GB Cheetahs in a RAID 1 config. creates one 9.1GB volume that automatically backs up your data onto the second drive. This config. is slower as it has to write two sets of data, but very useful for security purposes in case one drive fails. In the case of drive failure you simply go into your RAID utility and access the 'convert from mirror' command. This gives you access to your unharmed second set of data.

What you want to do is stripe the two drives in a RAID 0 configuration allowing you to use a faster 18GB set up.


"We clean the basement
of Hardware Heaven...
and like it!"

06-18-2001, 12:51 PM
Not to be nit-picky Spud, but I think "striping" is reserved for actual RAID-0 applications. There is no actual striping of data involved in a mirror. No more than there is in a simple volume.

RAID 4 is a neat concept. I can see why it would be an awesome thing for the Mac platform and the entire publishing realm. RAID 5? yeah, I believe that is what I would like for the home office. The speed of a RAID and an (almost) mirror without needing twice the amount of drives I really use, like a true mirror. For the ultimate in security and great speed, I would love to get some experience on a nice RAID 6. It actually allows for multiple drives to fail simultaneously and not bring the storage system down.

RAID 0+1 will be an awesome thing when it gets full support from SoftRAID.

06-18-2001, 01:57 PM
for further clarification on RAID, also see our RAID FAQ (http://www.macgurus.com/shoppingcart/obj_show_page.cgi?mgscsiraidfaq.html) on the main site.


06-18-2001, 02:03 PM
Great advice!

So, if I do the RAID-0 thing, I get a fast-as-snot single volume for work, etc. If I do the RAID-1 thing, I have only one active volume and it would be useful in a setting in which data conservation was tremendously important, e.g., a web server or a database server.

Okay. Time to funnel money into the credit card and call you guys!

06-20-2001, 03:23 AM

one thing to remember about RAID 1: while you take a performance hit on it, the data security you enjoy more than compensates, IMO.

I've been booting and running a heavily upgraded Yose for a few weeks now off a RAID 1, and it's working out very well.

For servers, most RAID 1 volumes are more than capable of saturating a network, so the performance hit is best understood in comparision to RAID 0 volumes, which are indeed "faster than snot" volumes best used to accelerate specific operations.

I have all my apps and many of my working documents on a RAID 0, backed up to a single fixed drive (and then to network backup from there). There are a variety of ways to use RAID 1 and RAID 0 volumes, and this is just one way.

It is a very, very cool technology.