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I have a problem with configure raid on red hat enterprise linux. The problem is when I create raid on two hard disks. It works successfully but after I remove one hard disk. It works normally. It means that I plug in one hard disk for testing configure raid. But after that I put both hard disks and create other file. The raid is cleared.

My question is:

Why do I turn off server machine, it clears raid that I configure first time before I turn off?

Could anyone help to solve this problem?

Thank, Ung Sopolin

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Can you be more specific? Hardware or software raid? Rail-1 I presume, but when you are talking about removing disks, which disk (ie disk0 or disk1), what do you do when the disk is removed, then you plug the disk back in, then what do you do, then you reboot? – David Mackintosh Aug 4 '09 at 17:19
My server I HP server. And I configure through software raid in Red Hat enterprise linux. – Sopolin Aug 5 '09 at 6:17
I unplug disk0 then I reboot the system. When I boot the disk 1, it has the os linus system. But after I put both disks and create other files for testing raid again. Mean that I unplug again. The raid is clear. – Sopolin Aug 5 '09 at 10:07

Devices are not re-added to the a software RAID automatically. Once you removed the drive from the array it was considered to be failed. You will need to manually re-add the device using mdadm.

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