[CentOS] adding a usb drive to an existing raid1 set

rado rado at rivers-bend.com
Thu Sep 28 23:16:56 UTC 2006


it seems like I keep running into a wall.
The present raid array...well let me do an fdisk -l:
----------------------------------------
Disk /dev/hda: 250.0 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/hda1   *           1          13      104391   fd  Linux raid
autodetect
/dev/hda2              14       27651   222002235   fd  Linux raid
autodetect
/dev/hda3           27652       30201    20482875   fd  Linux raid
autodetect
/dev/hda4           30202       30401     1606500    5  Extended
/dev/hda5           30202       30392     1534176   82  Linux swap

Disk /dev/hdc: 250.0 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/hdc1   *           1          13      104391   fd  Linux raid
autodetect
/dev/hdc2              14       27651   222002235   fd  Linux raid
autodetect
/dev/hdc3           27652       30201    20482875   fd  Linux raid
autodetect
/dev/hdc4           30202       30401     1606500    5  Extended
/dev/hdc5           30202       30392     1534176   82  Linux swap

Disk /dev/md0: 106 MB, 106823680 bytes
2 heads, 4 sectors/track, 26080 cylinders
Units = cylinders of 8 * 512 = 4096 bytes

Disk /dev/md0 doesn't contain a valid partition table

Disk /dev/md2: 20.9 GB, 20974338048 bytes
2 heads, 4 sectors/track, 5120688 cylinders
Units = cylinders of 8 * 512 = 4096 bytes

Disk /dev/md2 doesn't contain a valid partition table

Disk /dev/md1: 227.3 GB, 227330162688 bytes
2 heads, 4 sectors/track, 55500528 cylinders
Units = cylinders of 8 * 512 = 4096 bytes

Disk /dev/md1 doesn't contain a valid partition table

Disk /dev/sda: 250.0 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1               1          13      104391   fd  Linux raid
autodetect
/dev/sda2              14       27651   222002235   fd  Linux raid
autodetect
/dev/sda3           27652       30201    20482875   fd  Linux raid
autodetect
/dev/sda4           30202       30401     1606500    5  Extended
/dev/sda5           30202       30392     1534176   82  Linux swap



kk...the ide drives; hda and hdc...3 partitions 3 arrays md0 1 and 2 
cat /proc/mdstat shows it's acting as it should.

when I boot the system up, it sees the drive connect thru usb and calls
it sda (for what reason I don't know. I partitioned it to the same specs
as the 2 ide drives as per the bottom of fdisk -l. 

Now, trying to go by:
http://www.redhat.com/docs/manuals/enterprise/RHEL-4-Manual/admin-guide/
5.9.8.2 Creating RAID Arrays
they state the following:
Next, it is necessary to create the /etc/raidtab file. This file is
responsible for the proper configuration of all RAID arrays on your
system. The file format (which is documented in the raidtab(5) man page)
is relatively straightforward. Here is an example /etc/raidtab entry for
a RAID 1 array:

ummm...1.)I think this is part of the old raidtools thang...not mdadm
but I am not sure.
	2.) there is no man raidtab on this box which is a "everything"
install..

so considering this..lol I'm lost. 

kk, right now...I just formatted all the partitions and (I should have
done this before ) I am checking for bad blocks. If it finds some I'll
just redo it or whatever I have to do. At one point I was able to
mdadm /dev/md0 1 & 2 --add sda1 2 &3 and 
cat /proc/mdstat would show sda1 2 &3 as in the arrays but then they
would not populate.
I can't remember but I think I gave them mount points but wait, I was
having a hard time finding the proper syntax for that as well
anyway, after rebooting...it was all gone.

this ain't nice

thx

John Rose





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