RAID/hard drive questions for new build..

[Moki]

I've decided to purchase a mobo with SATA RAID capabilities, but after reading about setting up a RAID, I think I would want to wait for awhile before configuring my system this way since I have much to learn still. I do want to be prepared, however, so a few questions:

When a mobo says it has RAID 0/1/0+1 does it mean it actually has a controller card with it? I know this might be a dumb question for some, but I've never built a system before let alone fathomed a RAID.

If I have two HDs in a RAID set up, each at, say, 80GB, does that mean I only have 80GB of total storage if I use RAID 1 or 0+1? If using 0, then would I have 160GB total?

Can I just buy one drive for now and use it, purchase a second later and then set up a RAID with both of them without affecting my data?

Or, can I have two drives for my RAID and an additional separate drive that's not on my RAID? (how about an IDE HD along with a SATA RAID?)

I read in one of the step-by-step manuals online that you should install XP on a separate drive until you've configured your RAID, then switch it over to your RAID. I don't get why? Does this depend on the type of RAID your configuring? (This might answer my question regarding having a RAID and a separate drive at the same time or having existing data on one drive?)

I hope these questions aren't too juvenile, I've been reading on RAID, and the logistics haven't quite kicked in. I mainly want to know what I need to buy right now in the HD department to allow future RAID use. Any other thots or suggestions would be welcomed. Thanks!

[antgross@pacbell.net]

which mobo do you have (model number, make etc.)?

You don't need to worry about setting up RAID if you only have one Hard Drive. In fact, unless you are planning on doing some seriously HD intensive things (like video editing, etc) you won't need it.

You don't need to worry about mixing different HD on your mobo if you are not using RAID. It's only if you are setting RAID that you ideally want to be using same make, storage amt etc.

[Moki]

Sigh. I hate to go into morbid detail.... I am trying to build for the future. I am taking graphic comm classes and WILL be doing video editing, rendering, and who knows what else soon. I want to be prepared for what I may not know I need yet. SO YES, I will most likely eventually be using RAID. If for no other reason, because I want to say I've done it!

So, my questions remain. Thanks, anyway

Oh, I haven't purchased my mobo. I am trying to make final decisions today. I also want to purchase my hard drive(s) today, too, which is why all the questions. I have a P4 3.2GHz 478 800 MHz HT CPU. - see below!

[RJ]

When a mobo says it has RAID 0/1/0+1 does it mean it actually has a controller card with it?

Not necessarily. Some southbridges, like the Intel ICH5R and ICH6R, support RAID natively, so there is no extra controller needed.
Some mainboards might have an onboard controller anyway to provide you more SATA RAID ports than the southbridge can (ICH5R: 2x SATA RAID, ICH6R: 4x SATA RAID).
Mainboard that have southbridges without RAID capability do have an onboard SATA RAID controller if the specs say that SATA RAID is supported.

If I have two HDs in a RAID set up, each at, say, 80GB, does that mean I only have 80GB of total storage if I use RAID 1 or 0+1?

With RAID 1: Yes, you have 80 GB of total storage. The two hard drives have exactly the same data on it, they'll be used simulataneously for the same thing. The purpose of RAID 1 is safety. Whenever one of the drives fail, the other is a complete and current backup, so no data is lost.

RAID 0+1 is not possible with 2 hard drives. You need 4 for that.

If using 0, then would I have 160GB total?

Yes. With RAID 0 and two 80 GB hard drives, you have 160 GB of total space. But RAID 0 isn't really RAID, there is no redundancy (I guess therefore the zero). It's purpose is speed. The files get split to the hard drive that is ready to write. So parts of the files are written on one hard drive, the other parts on the other hard drive. If one hard drive fails, the entire RAID 0 setup is down for good.

RAID 0+1 would be a combination of RAID 0 and 1. You need 4 hard drives. Two of them are used in a RAID 0 setup for speed increase, and the other two are used in a RAID 1 setup for mirroring the RAID 0 drives. So you get speed and safety. If you're using four 80 GB hard drives, then you'll get 160 GB of total storage space (2x 80 GB = 160 GB for RAID 0, and the other hard drives only mirror, they don't increase capacity).

I mainly want to know what I need to buy right now in the HD department to allow future RAID use.

You need 2 hard drives of equal size, preferrable same manufacturer and same model.
For RAID 0+1 you need 4 hard drives of equal size, preferrable same manufacturer and same model.

Dunno about your other questions, though.

RJ

[Moki]

RJ...can you hear me say "Ahhhhhhh?" Very clear, concise answers, thanks!

If anyone can answer the other questions, I would be very grateful. I'm thinking of getting a 160GB HD now, and would like to convert it later to RAID with another matched HD, if possible.

Here's the pertinent specs on the mobo I'm looking at. Seems it has both the native (ICH5 SB) and an onboard controller like you said? Don't know what Promise 20378 is...

Chipset: Intel 875P + ICH5
Onboard SATA/RAID: Promise 20378, 2x SATA, RAID 0/1/0+1/Multiple RAID; ICH5, 2xSATA

[RJ]

Here's the pertinent specs on the mobo I'm looking at. Seems it has both the native (ICH5 SB) and an onboard controller like you said? Don't know what Promise 20378 is...

No. The ICH5 does not have RAID capabilities. The ICH5R does (R for RAID).
Promise is a manufacturer for controller cards. An excellent one. So the board you're looking at has an onboard Promise controller that provides you 2 SATA ports capable of RAID.
The ICH5 provides you 2 SATA ports incabable of RAID.

So you have 4 SATA ports in total, and only 2 of them support RAID.
That actually indicates that the answer to this question

Or, can I have two drives for my RAID and an additional separate drive that's not on my RAID? (how about an IDE HD along with a SATA RAID?)

is yes. You can use the Promise SATA as RAID, and the Southbridge SATA and PATA as non-RAID. I just checked, it's possible.

RJ

[Moki]

Oops. That pesky little "R" slipped right past me. Well, it still has a RAID controller which suits my purposes, danke...

So many questions.... which lead to more questions...

[Spartan]

RJ always does such a good job answering questions that he leaves very little for anyone else to add....lol.

Can I just buy one drive for now and use it, purchase a second later and then set up a RAID with both of them without affecting my data?

As RJ said you ideally want the same manufacturer and model (although it is possible to do raid arrays with drives of different capacities and different manufacturers, you just are risking more problems) so be sure to pick a popular drive that is likely to be around for a while. You can use an existing HDD to create a Raid 1 only. It will take the the data from the existing drive and mirror it onto the backup drive. I have done this on native ICH5R, promise, and adaptec controllers. You cannot create a Raid 0 or 0+1 with an existing HDD and keep the data that is on that HDD. The controller cannot take the existing data and split it up between the existing HDD and the new HDD.

Or, can I have two drives for my RAID and an additional separate drive that's not on my RAID? (how about an IDE HD along with a SATA RAID?)

Yes you can add another drive to the same system that has a Raid array and it can be IDE or SATA (assuming you have an open port for it).

I read in one of the step-by-step manuals online that you should install XP on a separate drive until you've configured your RAID, then switch it over to your RAID. I don't get why? Does this depend on the type of RAID your configuring? (This might answer my question regarding having a RAID and a separate drive at the same time or having existing data on one drive?)

Some people recommend this because XP doesn't come with the drivers needed to support Raid if your Raid is built into the mobo. They will be on the mobo disk and you have to save them to a floppy which you use to install them during the installation of XP (or whatever OS you are going to be using). Since you, in essence, have to install the drivers and build the array all at the same time it is sometimes easier to do it if XP is already up and running. It doesn't really matter what Raid you are setting up.

Alot of people knock Raid and say the speed increases are only noticeable in a benchmark test. I would say for the average user this is probably true, but for the use you are looking at I think it will be worthwhile. I have been doing alot of home movies and I can definitly see it run faster. My machine has 2 74 gig Raptors in Raid 0 and two 200 gig drives in Raid 0. I recently added another 250 gig external drive. It runs smooth as butter with no probs.

-Spartan

[Moki]

I can't tell you how much I appreciate answers that are so precise and easy to understand - thanks, guys for taking the time to look into my questions! Impressive.

Now that I have this info, I'm a little stumped as to how to proceed. Should I go ahead and get a 160GB SATA for now just so I can get started, then set up two 80Gbs on RAID 0 later? Or with my rendering programs, should I have them on 160GB RAID 0 and an 80GB SATA alone? I still don't know what to expect as I begin to work with my applications, (next quarter) and I don't want rendering to crawl if I can make a difference w/my hard drives. Any ideas on how to proceed? Something different maybe? My son will want to game a little on this computer, too, (when he can pry me off of it) so what should I start with?

[zip86]

Originally Posted by Spartan Alot of people knock Raid and say the speed increases are only noticeable in a benchmark test. I would say for the average user this is probably true, but for the use you are looking at I think it will be worthwhile. I have been doing alot of home movies and I can definitly see it run faster. My machine has 2 74 gig Raptors in Raid 0 and two 200 gig drives in Raid 0. I recently added another 250 gig external drive. It runs smooth as butter with no probs. -Spartan

Maybe it your raptors that make your comp faster, not your raid 0. I don't use raid 0 but most everyone says its not a huge difference, but the raptor 10000RPM is 33%(?) increase in speed from the 7200RPM.


About using Raid 0 160 or Raid 0 80MB, I would go with a smaller size raid 0 as the master for running programs and use a large archieve slave hd to store anything that you are not working with. A large Raid 0 means that if you lose one of your hd, you lose everything which is very risky.

[glc]

If cost is not really an object and you want speed, get a single WD Raptor - either the 36gb or the 74gb - and put your OS and applications on it standalone SATA. Then you can get a pair of drives and put them in RAID 0 for storage, rendering, etc.

[Moki]

Well, that certainly makes sense. This is good because I feel better about just purchasing a 160 GB SATA right now. But about those Raptors.....? 10000 rpm? darn it... something else to consider again. That'll have to be for my RAID, I guess. So do I need anything special (mobo wise) to step up to the increased RPMs? (See what you did, Spartan?)

[zip86]

Nothing special for 10,000RPM. HD are usually the easiest to upgrade. Just be aware that the new 10k RPM are very expensive and limited space. Doing what glc said is probably your best bet.

[Moki]

Sorry GLC, I posted before I saw your comments. Well, what Zip86 said seemed to make sense about putting my appliations on the RAID and things like photos, videos, other mostly archive-type stuff on my larger single hard drive.

But you say to put my apps and OS on a single SATA Raptor (must be faster than a small RAID?) And, forgive my ignorance, but when rendering, that's part of an application is it not? That would then be on the Raptor? And why put storage on a RAID?

Money is a consideration, of course, but I'm willing to go extra to be satisfied with my system for a few years as I learn my new field. And I want to do it right, so I'm all ears.

[Spartan]

Well the way I do it is to have my OS and apps on the Raptors. I store all of the raw footage on the normal Sata drives and do the creation back on the Raptors. Then I save the completed project back on the normal Sata's. If it is really good and I want to back it up I save it also on the external. Did that make sense?

I am totally sold on the Raptors and will never have another computer without one (or it's current model/equivalent). Things just load and boot so much faster it seems. If I were you I would do as glc suggested and start with a Raptor and add the big Sata's in Raid later. I know programs are big these days but 74 gigs is still quite a bit of space.

-Spartan