RAID Array

[Greg Carlson]

Steeve,

It is my understanding that you can't go from a two disk raid 0 to a two disk raid 1 configuration as there isn't enough room for the data to be restriped onto a single disk. You may only have had enough data to fill up one hdd, but remember its striped equally across the two hdds. If you are in a 2 disk raid 0, I believe your option is to add another hdd and then convert from raid 0 to raid 5. This will give you the capacity of 2 drives with 3 installed. Your capacity will always be x-1.

Sorry to hear all of your unfortunate adventures with raid 0. Raid 0 is what you use for non-critical data as once you lose the drive, thats it. Only option to recover data at that point would be data recovery.

Ciao,
Greg

[Steeve Hébert]

Hi,

If I make it in two steps ???

First one : Go back to 1 disk.

Second one : Build mirror.

I'm sure that I can store all my data on 1 disk because it was like that before and I didn't add some data.

I will try to go back with the ACU.

Thanks

[Steeve Hébert]

Hi,

I looked the ACU.

If I remove a disk from the RAID 0 all the data will be lose.

Question : If I add an IDE drive in the server an use Windows 2000 to make a software mirror of my RAID 0... Does it make sens ???

Thanks

[Greg Carlson]

Steve,

Hi,

I looked the ACU.

If I remove a disk from the RAID 0 all the data will be lose.

Question : If I add an IDE drive in the server an use Windows 2000 to make a software mirror of my RAID 0... Does it make sens ???

I can't think of anything worse to do than this... if you must use an IDE drive to copy the data off the SCSI hdd until you can reconfigure it properly, that is one thing. The IDE hdd and SCSI hdd operate at very different performance levels and you will end up with even more problems. Stick with hardware RAID because you paid for it with your proliant. And yes, removing any hdd from a RAID 0 loses the entire raid set.

Ciao,
Greg

[Steeve Hébert]

Hi,

Yes, I know that IDE disks are worse then SCSI. But it's only to backup the server. Then I will remove a drive from the RAID and put back the data from the IDE to SCSI.

Is it good ?
(Or possible with Win 2000 software mirror)

Thanks

[JohnWRuffo]

Steeve:

The ProLiant ML370 does not have direct support for IDE drives. The drive likely will not boot of the internal IDE controller. Only support for CD-ROMs and such.

[Gerhard Roets]

Hi STeeve

As propably stated before.

RAID0 ... is not RAID at all but one big hairy accident waiting to happen :P It is nice for true temporary non business critical no need to recover space. Performance is great for reading and writing. And it is extremely cheap on the resources/ disks to create space. If you loose ONE disc you loose it ALL

RAID1 ... is raid but it is more expensive because you need to buy double the disk. It is fast and balanced on reading and writing. You can loose half the disks if you loose the right ones. If you loose two disks in a mirror pair you loose it all(dependant on implementation).

RAID5 ... cheaper than RAID1 more expensive than RAID0. You can loose one drive in a redundancy group. It is fast on reading but slower on writing. This does depend on the implentation though.

Off course you can add hot spares to rebuild on. But the rebuild is NEVER instantaneous. So you have exposure ib the rebuild time. Adding hotspares does add to to price though.

Sorry to chip in here even though you had answers before it justs drives me up walls if some one sets up raid0 for production achines :P I had to explain this a few times ...

Regards
Gerhard

[Steeve Hébert]

Hi,

A new disk is 800$.
(That's the cost of learning... )

I think that I will buy a new disk and add it to the array.

The array will then become fault tolerante.
So, if a disk of the array die, the server will continue to work...
( Correct ? )

Thanks

[Gerhard Roets]

Good idea but remember a few things

not raid0! :P Alo use the hp agents to monitor your device. If a disc fails you should not now about this ... but you should get notified about it else the disc will never be replaced.

Also remember raid does not protect you from files being erased or fs/os corruption ... so raid does not replace a good backup strategy, it augments it.

Regards
Gerhard

[Greg Carlson]

Steve,

When you add that $800 disk, make sure that you change raid levels from 0 to 5 instead of just expanding the array and leaving it a raid 0. Then you would still be with no redundancy.

Good luck.

I would also recommend looking at this link for some more detailed understanding of how RAID levels work.

http://www.acnc.com/raid.html