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RAID 5 /RAID 1 question

Vivek Desai
Occasional Advisor

RAID 5 /RAID 1 question

Hello,

We have a proliant 350 G with a Smart Array 641 controller. We currently have 3 drives on a RAID 5. I would like to add 2 more drives (36.4 each)and have a RAID 1 on them. My question is will it be possible for me to only have like 10 gigz of the new disks on a RAID 1 and add the remaining space to the existing RAID 5. I dont think this is possible but just wanted to double check.

Also when I add the 2 drives as a RAID 1..how will Windows see it. Currently I have an E drive which is around 65 gigs through the 3 disks since its a RAID 5 and the remaining space for C. Can I add the new space which is created by adding the 2 new drives as a RAID 1 to the E drive. or will I have to assign a different drive letter in windows. My main concern is since I will be only be using half the disk space of the 2 drives and also the I just need about 10 gigz space as a RAID 1 to save our SQL server log files..so any space on top of that would really be wasted using a RAID 1. Please let me know your thoughts.

Thanks

Vivek

Best Regards

Vivek
4 REPLIES
Prashant (I am Back)
Honored Contributor

Re: RAID 5 /RAID 1 question

Hi,

Q)We have a proliant 350 G with a Smart Array 641 controller. We currently have 3 drives on a RAID 5. I would like to add 2 more drives (36.4 each)and have a RAID 1 on them

a) Yes can be done.

Q) My question is will it be possible for me to only have like 10 gigz of the new disks on a RAID 1 and add the remaining space to the existing RAID 5

Q) Also when I add the 2 drives as a RAID 1..how will Windows see it. Currently I have an E drive which is around 65 gigs through the 3 disks since its a RAID 5 and the remaining space for C.

A)As new logical drive avaible

Q)Can I add the new space which is created by adding the 2 new drives as a RAID 1 to the E drive. or will I have to assign a different drive letter in windows. My main concern is since I will be only be using half the disk space of the 2 drives and also the I just need about 10 gigz space as a RAID 1 to save our SQL server log files..so any space on top of that would really be wasted using a RAID 1.

A)Cannot mix disc from RAID 1 to RAID 5 both are diff raid.

Hi am attaching a link also a good for smart array controller.
http://h18004.www1.hp.com/products/servers/proliantstorage/arraycontrollers/documentation.html

Regards,
PRashant S.






a) NO
Nothing is impossible
Uwe Zessin
Honored Contributor

Re: RAID 5 /RAID 1 question

Hello Vivek,
let's see if I understand you correctly.

You have an array (A) of 3 physical disks. There is one logical disk in RAID-5 carved out of that array. Then you want to create a second array (B) of two new disks. You want part of this array allocated to a new logical disk in RAID-1. Fine, so far.

Unfortunately you cannot assign the remaining space in array B to expand the logical disk in array A.

A new logical disk on the Smart Array controller will result in a new disk on Windows. Can't you use Windows to combine the two disks?

A (drive) array, by the way, is just a means to collect a few physical disks. It does not have a RAID-level attached to it - that is a characteristic of the logical disk.

How big are your disk drives in array A? If they are 36 GBytes as well you could do the following:

- expand array A with your new disk drives

- extend your logical disk in RAID-5 mode

- create a new logical disk in RAID-1 mode in array A. The downside is that logical disks must deleted in reverse order - you cannot delete the RAID-5 logical disk before you have deleted the RAID-1 one.

- next you resize the E: partition. Else you
will just see free space at the end of the extended disk

(I see that Prashant has already answered, but I started when no response was there and I put some effords in my thought, so I want to show them anyway.)
.
Vivek Desai
Occasional Advisor

Re: RAID 5 /RAID 1 question

Hello Guys,

Thanks for your responses. I am clear on most issues. Just 1 more question. So once I create an Array B and have 2 physical drives on a RAID 1, Windows will see that as empty space.

Will Windows show/see this new space available on a Disk 1?

Currently all my disk space shows up in Windows on Disk 0.

If the above is true can I combine the new space from the Disk 1 to the existing logical E drive on Disk 0 or will I have to create a new logical drive and assign it a different drive letter .

Thanks

Vivek
Vijay_44
Honored Contributor

Re: RAID 5 /RAID 1 question

The new logical drive (Logical drive 2) that you create will be seen by windows as DISK 1.

The second part of the question is windows related:
If you are using Windows NT, then yes, you can combined space from DISK 0 and DISK 1 to creat one big partition E

If you are running Windows 2000 then it depends - Have you implemented dynamic disks or basic disks. In windows 2000 you cannot span basics disks. If you have dynamic disks, did you create E before the conversion to dynamic or after; if you created E before (ie on a basic disk) the you cannot do anything with E; but if you created E after converting DISK 0 to dynamic then yes you can have one big E partition spanning DISK 0 and DISK 1

If you are using some 3rd party disk utility then you may be able to span regardless of disk type; of course it depends on the utility you are using.

http://support.microsoft.com/default.aspx?scid=kb;EN-US;225551
There’s your problem!!! This thing is set to EVIL!