Linux - HardwareThis forum is for Hardware issues.
Having trouble installing a piece of hardware? Want to know if that peripheral is compatible with Linux?
Welcome to LinuxQuestions.org, a friendly and active Linux Community.
You are currently viewing LQ as a guest. By joining our community you will have the ability to post topics, receive our newsletter, use the advanced search, subscribe to threads and access many other special features. Registration is quick, simple and absolutely free. Join our community today!
Note that registered members see fewer ads, and ContentLink is completely disabled once you log in.
If you have any problems with the registration process or your account login, please contact us. If you need to reset your password, click here.
Having a problem logging in? Please visit this page to clear all LQ-related cookies.
Introduction to Linux - A Hands on Guide
This guide was created as an overview of the Linux Operating System, geared toward new users as an exploration tour and getting started guide, with exercises at the end of each chapter.
For more advanced trainees it can be a desktop reference, and a collection of the base knowledge needed to proceed with system and network administration. This book contains many real life examples derived from the author's experience as a Linux system and network administrator, trainer and consultant. They hope these examples will help you to get a better understanding of the Linux system and that you feel encouraged to try out things on your own.
Click Here to receive this Complete Guide absolutely free.
I was recently charged with increasing the storage of a linux file server. Seemed simple enough at first, I figured it could be done in an evening without too much effort. Then I found out that the megaraid controller wasn't recognized by any bootable CD I had. The particular raid controller is an American Megatrends Megaraid version 02.
In the end, with a current debian testing image, I did get the system running with three new drives in a raid5 array, and I did do it in the evening I had alloted for it. But when I went back to install the machine the next day, I discovered I had not copied all the files I needed to before I took the old drives out, and the machine was back in production, so I couldn't exactly shut it down and put the old drives in. Besides, even if I had done that, I am not sure that the megaraid controller would see the old raided drives, now that the controller has been reconfigured with the new drives.
I figured I could use software raid to recreate the array, and after some poking around, I did find a few posts on people who had used that trick for a raid0 and raid1 config, and one who had used his skills as a java programmer in conjunction with gnu/linux to recover a raid5 of 5 disks.
I have the drives in a machine and have booted up with the gparted live cd, but nothing really seems to be functioning the way I had hoped. /dev/hda-b-c are the three drives, /dev/hdd is the cd. querying the drives with madam -Q tells me /dev/hd* is not an md array, and mdadm --examine tells me there is no md superblock detected on any disc, or any partition thereof. parted tells me /dev/hda and /dev/hdb have paritions outside of the disk, and /dev/hdc is an unrecognized disc label. ls /dev/hd* seems to indicate there are 4 partitions on hda and hdb, but no partitions on hdc.
I have perused the man page for mdadm, and do not see any other options for recovering the array this way.
So now, while I am doing this post, I am also looking for documentation on the particular raid controller to see if I can put the drives back in the original machine without danger of losing the data. But I am hoping somebody has some other ideas for me to try using mdadm or some other piece of software available to the linux world...
All comments appreciated...
I have a fair bit of experience with 3ware, software, and other RAIDs. One important distinction is hardware vs software RAID. The mdadm utility may only be used for management/recovery of software RAIDs. Almost all hardware RAID controllers use their own proprietary formats for the drives, which will make it difficult for recovery without re-connecting it to the hardware controller.
Yes, recovering a RAID1 from a hardware controller should be pretty easy. Recovering a RAID5 will be more difficult, because you have to reverse engineer the chunk sizes and rotating parity.
However, you should be able to safely re-connect the old drives to the RAID controller. They are designed to allow this.