What is RAID ?? 4

[vrcatherine]

Hi,


I am completely new to the hardware stuff and wanted to know what exactly RAID means ( not the abbrevation).


Some kind of mirroring I guess , can some one
explain me in layman terms. (raid ,0,1,5)


--thanks
Cathy

 

[Blujacket]

Try this:

http://www.webopedia.com/TERM/R/RAID.html

 

[TekTippy4U]

http://fae.abit.com.tw/eng/faq/qa/2001/2001032001.htm

http://fae.abit.com.tw/eng/faq/qa/2001/2001032002.htm

http://www.hardwaresite.net/hpt370.html

TT4U

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[vrcatherine]

Ok, I had read the links what you people had given.


Correct me if i am wrong :

Now few quick questions:


I wanted to have a server with 3 disks and i wanted
to go with RAID (mirroring RAID 1).

1) Now to do this i need to get altogether 6 IDE or SCSI
drives?

2) In a normal windows 2000 environment server, does the
windows explorer show all the 6 drives or 3 drives only?

C: D: E:
3) What kind of software do I need to configure these
RAID's ? Does it come with the hardware or I need
to buy some software?

4) If i wanted to go with RAID 1 ( just mirrong of drives)
do i need to have altogether 6 hard disks IDE's or SCSI
first plugged in ?


--Thanks
Cathy

 

[Freestone]

I suggest reading this comprehensive RAID documentation too:

http://www.pcguide.com/ref/hdd/perf/raid/index.htm

 

[Freestone]

To answer some of your questions:


1) Mirroring requires 2 drives per mirror set, so yes, 6 drives are required. Your controller will determine the type, SCSI or IDE.

2) Explorer will show three drives - C: D: E:

3) RAID can be accomplished through a software only solution, though it's not recommended. A hardware RAID controller would provide the tools required to build your mirror sets through its onboard BIOS. Some controllers also provide management tools that can be run under your OS once it's installed.

4) You'll have to start with at least 2 drives plugged, assuming you are going to mirror your OS drive.

 

[vrcatherine]

Thanks for the reply.


1) Lets say I go with the RAID 1 ( 3 drives ) total of
6 with mirroring, and windows explorer wil show
3 disk C:\ D:\ E:\ .

And one of the disk went bad (D:\) will the OS
automatically detect and start using the mirror disk
of D:\ ( will it throw some error ) ?


2) Does the RAID still keep working , or I have to replace
the original D:\ drive ?

--Cathy

 

[Freestone]

The handling of a failed array member in a RAID set is the responsibility of the RAID controller. In general, the OS won't know about the failed drive as it only sees the mirror set as a logical volume, it knows nothing of what makes up that volume. Usually the RAID controller will switch over to the good drive and keep working, but it depends on the controller. You should review the documentation of any RAID controller you may be thinking of using to see if it handles errors the way you want, along with how it communicates these errors to the outside world.

In any case, the failed drive in a mirror set should be replaced ASAP as your redundancy has been lost. If the second drive fails before the first failed drive is replaced, then you've lost all data.

The comprehensive guide I posted a link to earlier covers these points, and others as well.

 

[vrcatherine]

Is there a way in Windows 2000 server to check
as how the RAID or mirroring is being setup ?


I already have a windows 2000 server which someone
said that its configured to RAID.

How can i check this ?

 

[Freestone]

Disk Management would reveal any type of software RAID Windows itself is managing. Device Manager should reveal any hardware RAID controllers, and these controllers usually have some kind of management program that you can run under Windows.

 

[TekTippy4U]

I'm learnin something here....so a *..

TT4U

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[vrcatherine]

Ok here is what i see on my server, plz. go through it and
let me know how its been setup.

1.
====================================================
When i boot the system it comes up with a FastBuild utility
screen (Ctrl + F) and this is what i seen on the screen


1 MAS MAXTOR 6Y120P0 122880M ARRAY 1 U5
2 MAS MAXTOR 6Y120P0 122880M ARRAY 1 U5

====================================================





====================================================

Disk Management Info:


Volume Layout Type Status Capacity Free

C: partition Basic Healthy 19.53GB 16.7GB
(system)
D: partition Basic Healthy 19.53GB 19.47GB

E: partition Basic Healthy 39.06B 39.00GB

F: partition Basic Healthy 36.36GB 36.30GB



==========================================




Under Device Manger => SCSI and RAID controllers

WinXP Promise FastTrack100 (tm) Controller


=============================================


Under Device Manager => IDE ATA/ATAPI controllers

Primary IDE Channel
Seconday IDE Channel
VIA Bus Master IDE Controller


================================================






--Thanks
Cathy

 

[TekTippy4U]

Look under Disk Drives in Device manager as well

it "seems" you have [1] RAID 1 Array Setup (careful, not 100% positive)

Under Device Manager => IDE ATA/ATAPI controllers

Primary IDE Channel
Seconday IDE Channel
VIA Bus Master IDE Controller

this controls the Standard IDE Interface....whereas the RAID controller has 2 separate (sometimes 4) connectors for the RAID array.....so the usual basic sys that could only have 4 IDE devices in the past (2 IDE channels)
1.Primary
2. Secondary
-each w/Master and Slave capable = 4 total). as shown in italics above, controlled by the VIA Bus Master IDE Controller

*-can now (with RAID Controller Added, either Onboard or PCI Card) have 6-8 Total IDE devices.

WinXP Promise FastTrack100 (tm) Controller
This is controlling your RAID array

TT4U

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[TekTippy4U]

Here's a small spec for the maxtor drives
120 GB Internal Drive
7200 rpm Rotational Speed
9 ms Access Time
DMA/ATA-133 (Ultra) Fast Drives Interface

It "seems" (again careful)
XP has been set up for a Software RAID, by breaking 2 MAXTOR HDD (240GB total)...used in a RAID 1 array = 120GB available.
4 partitions = 120GB
broken into 40,40,20,20GB each

Please wait for someone more knowlegeable.....before doing anything at all, as I'm not sure...

TT4U

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[rclarke250]

It's a hardware raid with the promise ide raid chip. But yes it is partitioned into 4 partitions. You can not go to 6 drives in this setup. You would need to go to another controller to do it. Actually it is recommended to go to SCSI Raid on a server, A 3 channel card could hold 45 drives,usually in an external enclosure. A raid 5 system is usually a better fit for a system then mirroring. In a mirror you loose 1 of every 2 drives to redundancy. Now my question is why to you want 3 seperate drives,mirrored? why not one large array partitioned into 3 different logical drives? simialar to the 4 partition system you have.

Rich

I shall use google before asking stupid questions!

 

[TekTippy4U]

Thanks for clarifying that part for me Rich
you take it from here and i'll watch.

TT4U

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[Freestone]

I can't add much that Rich and TT4U haven't already covered.

You have a hardware RAID controller (Promise FastTrack100 Controller) which has two drives attached, configured for RAID 1 (mirroring). This mirror set has been partitioned into four.

A quick look around with Google reveals that this type of controller is limited to mirroring, with the TX2 model supporting only two drives, and the TX4 supporting four drives. The Promise site itself lists only the TX2 model.

Rich is correct that SCSI RAID, configured for RAID 5, is usually used in a server environment, but be prepared to pay a higher price for it.

 

[TekTippy4U]

vrcatherine;
just want to add something to hopefully clear up some confusion you may have;
You have 1 mirror RAID Array (2 HDDs(HardDiskDrives), and you asked about using 6 HDDs.
Well with the way your 1 is set up into 4 partitions
(C:E:F
If you mutiplied that by 3 (2 HDD x3 MIRROR ARRAYS) and you partitioned it the same way, you'd end up with 12 partitions
(G:H:I:J
(L:M:N:O

I ONLY say this above to illustrate the question you asked about "What Drive Letters you'd see"

Way up in the thread's beginning, it was assumed that C:E: would be seen only - and this would apply with 6 HDD - ONLY if each RAID Mirror Array had ONE PARTITION EACH.
So What you'd see "depends" also on How Many Partitions are created.

Now forget all that - and listen to Rich and Freestone about SCSI Controllers and running RAID 5 on a Server...
hth

TT4U

Notification:
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[vrcatherine]

Thanks for & all for your valuable input.


I will go with the current configuration what I have.


2 SCSI drives mirrored ( array 1) 120GB x 2 = 240GB

4 logical partitions.



---Thanks
Cathy

 

[jurgen36]

Sorry there is something wrong. If you mirror two 120 Gb drives you only have a total of 120 Gb to use. However if you use raid 0, which is not mirrored then you have 240 Gb available. Regards

Jurgen