how to use two disk whithout raid

[Gianfranco Ferrini]

Hi,

I have a proliant dl585 g6, and I would like
to use two hd with no raid at all.

Is it possible to disable raid and use only
hd as single one?

Thanks

[Torsten.]

I don't know why you want to do this, but consider to create a RAID0.

[Gianfranco Ferrini]

If I create raid0 for each hd, I can't place it
in another server or I cant't make a clone of
the disk and put it in another proliant.

This is why I need don't use raid at all.

[Johan Guldmyr]

Hi, the RAID configuration is saved on the disk and in the smart array controller.
So if you create an array with a disk and move it, the new smart array controller will recognize the raid0.

[Michael A. McKenney]

Never, ever do RAID 0 on a production server. If one drive fails, you lose everything. Do RAID 1 or single drives. I would do RAID 1 for redundancy in case a drive fails.

[Johan Guldmyr]

Michael: Single Drives would be configured as raid0 wouldn't they?

[Michael A. McKenney]

You mutliply your rate of failure with RAID 0 by the number of drives.

2 drives increases your failure rate by 50%
3 drives by 66%

On file servers it is more important to protect your data. Why would you want to increase your risk probability factors. RAID 10 is a safer way to increase read and write performance.

[Johan Guldmyr]

So with less drives he has less chance of drive failure? :)

I don't know, maybe Gianfranco want to reply if they have a good reason why they don't want to use raid?

[Michael A. McKenney]

RAID 1, 10, 5, 50, 51, 6, 61 are all fault redundant. You can also setup hot spare or just spare drives for automatic fail over. Fault redundant means a drive can fail and you still remain up and running in a degraded state. So you risk of failure is two drives instead of one. You lose the first drive, you are still up and running. With a spare set properly, it begins to rebuild the array. Without a spare, you have to replace the drive. Once the array is rebuilt to a spare drive, you replace the bad drive and make that your new spare.

Hot spare means it can be changed live and in production. Spare means you shut down and replace the drive. Most HP server come with hot enclosures.

You can place a spare in any slot. in the setup you set it as a spare.

Global spare means it goes for all arrays.
spare for certain arrays.

Any drive same size or larger can be use to fail over to or replace a bad drive.

I recommend one spare per array.

[Gianfranco Ferrini]

Thanks to all for your reply.

My scenario is this.

I have three proliant dl585 and I want to reply the same configuration, I mean the same OS and virtual machine.

I setup the first server with two radi0 disk, installed redhat6 and then two virtual machine.

Now I would like to reply the same on the other two proliant, without to have to reinstall everithing.

If I make a ghost of the hd, this fail when I put the new disk in one of the another server, because of the controller raid.

There is a way I can do this?

Thanks

[Michael A. McKenney]

RAID 0 is never recommended for a production server. It is not supported by Microsoft, Novell and many Linux providers. Lose a disk and you lose the array. You should do RAID 1 for OS and paging/swap files. If you want to do two separate disks, One for OS and one for apps/data. That would be safer than RAID 0. I would get a proper backup solution other than ghosting. You need to recover your directory services.

[Johan Guldmyr]

Hey, so what OS are you running?

Making ghosts/copies of windows installations used to cause problems with the SID - which required some work afterwards. I do not know if this is the case.

How did you make a ghost of a disk? How did you try to restore it? Did you have the same hardware settings/raid setup?

HP has a tool called RDP - rapid deployment pack - which simplifies installations a lot (when it's working).

[Michael A. McKenney]

The problem with ghosting is hardware changes. Ghosting is not the best backup solution. You could setup a workstation and do disk to disk backups to it. I prefer a backup solution you can take offsite. We have been working with a Barracuda device to move three databases offsite. The 900 GB of data is still backed up to tape and took off site. The Barracuda is to make a psuedo DR site available.

[Gianfranco Ferrini]

Hi,

my problem is not backup, I want to clone an entire disk on another one.

I use acronis as clone software and, I repeat, it doesn't seem to be possible whith raid controller.

This is why I ask if it is possible to see one single disk without raid (if I want i can do raid also with linux software)

The OS that I use with my machines is RedHat 6.

Thanks.

[Michael A. McKenney]

You can do RAID 0 on single drives. You can replace the RAID controller with a SCSI/SAS controller.

[Torsten.]

Regarding the clone: Consider to create a RAID1 on 2 disks, so you can transfer the OS with the disk to another server.

Regarding RAID controller: I'm only aware of a single controller model where you can enable or disable RAID functionality, but this is in the BL860c i2 blade, not on proliant.

[Michael A. McKenney]

I would do RAID 1 on the two drives and get a separate backup solution like a USB 2 drive or tape backup solution. I would not do hard drive removal. The backplane is not designed for daily removal. You will damage a drive or backplane over time.

[Gianfranco Ferrini]

Thanks everyone for the answers.

The end result is that you cannot disable raid controller and clone disks must be done through backup systems.