Configure RAID

[thirst4knowl]

Hello Sir,

I want to Setup RAID 0 on my standalone
system. I have windows and linux both on my system. I
went through many documents and and also through the
book 'Managing RAID on Linux ' by Derek Vadala. I
tried to setup RAID with the following steps. I
downloaded mdadm from your site. I have listed down
the steps i did with their outputs. Please if you
could go through it and let me know where the problem
lies, it would be of great help.

1. I was able to include the RAID modules with the---insmod raid0.c
. The mdstat file was as below.

bash2-2.05b# cat /proc/mdstat
Personalities : [raid0] [raid1]
read_ahead not set
unused devices:

---------------------------------------------------

2. I had partitioned the disk using disk druid and the
partition table looked like below

Disk /dev/hda: 40.0 GB, 40020664320 bytes
255 heads, 63 sectors/track, 4865 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/hda1 * 1 1275 10241406 7 HPFS/NTFS
/dev/hda2 1276 1307 257040 83 Linux
/dev/hda3 1308 4507 25704000 83 Linux
/dev/hda4 4636 4865 1847475 f Win95 Ext'd (LBA)
/dev/hda5 4636 4700 522081 82 Linux swap




------------------------------------------------

3. Then I worrked with the following command.
I got the following error.

bash2-2.05b# mdadm --create /dev/md0 --level=0
--chunk=32 --raid-disks=2 /dev/hda2 /dev/hda3
mdadm: /dev/hda2 appears to contain an ext2fs file
system size=10241404K mtime=Sat DEC 27 17:06:24 2004
Continue creating array? y
mdadm: ADD_NEW_DISK for /dev/hda2 failed: Invalid
argument

--------------------------------------------------

4. When i again tried with that command, it showed
the following error.

bash2-2.05b# mdadm --create /dev/md0 --level=0
--chunk=32 --raid-disks=2 /dev/hda5 /dev/hda4
mdadm: /dev/hda2 appears to contain an ext2fs file
system size=10241404K mtime=Sat DEC 27 17:06:24 2004
Continue creating array? y
mdadm: SET_ARRAY_INFO failed for /dev/md0: File
exists

---------------------------------------------------

5. the mdstat file was same

bash2-2.05b# cat /proc/mdstat
Personalities : [raid0] [raid1]
read_ahead not set
md0 : inactive
unused devices:



--------------------------------------------------
when i typed dmesg,following where the recent messages:

md: raid0 personality registered as nr 2
md: raid1 personality registered as nr 3
md: linear personality registered as nr 1
md: can not import hda2, has active inodes!
md: error, md_import_device() returned -16

sir i request you to help me in this regards,

Hello Sir,

I want to Setup RAID 0 on my standalone
system. I have windows and linux both on my system. I
went through many documents and and also through the
book 'Managing RAID on Linux ' by Derek Vadala. I
tried to setup RAID with the following steps. I
downloaded mdadm from your site. I have listed down
the steps i did with their outputs. Please if you
could go through it and let me know where the problem
lies, it would be of great help.

1. I was able to include the RAID modules with the---insmod raid0.c
. The mdstat file was as below.

bash2-2.05b# cat /proc/mdstat
Personalities : [raid0] [raid1]
read_ahead not set
unused devices:

---------------------------------------------------

2. I had partitioned the disk using disk druid and the
-- INSERT -- 5,1 Top


sir i request you to help me in this regards,

punit(punit2410@yahoo.com)

[Belisarius]

A) I don't see any point in setting up a RAID on a single disk. RAID 0 improves performance over *multiple* disks. RAIDing the partitions on a single disk will actually hurt performance. mdadm might actually be confused as to why in the world you're RAIDing partitions on the same disk, and that could be causing the error.

B) You need to make the partitions to be RAIDed a Linux RAID filesystem ('fd' in fdisk).

C) RAIDed partitions should (and I can't emphasize that enough) be the same size. You are RAIDing partitions that are different sizes by a factor of 100.

D) The array might very well have been created after the first try, just without the disks you wanted. At that point you'd need to stop the array and get rid of it.

E) Grab Webmin. It lets you do the whole thing from a nice web-based GUI, making the process a great deal simpler.