I've been trying to bring up a RAID10 device, and I'm having some
difficulty with automatically-created device names.
mdadm version 2.5.6, Debian Etch.
With metadata=1.2 in my config file,
mdadm --create /dev/md/all --auto=p7 -n 4 --level=10 /dev/sd*2
This does seem to create a RAID array. I see that my /dev/md/ directory
is populated with all1 through all7.
On reboot, however, I notice that there's a suddenly a /dev/md127
device. Confused, I attempted to start over many times, but I can't seem
to create a non-"all" array and I can't seem to create a simple
/dev/md/0 array.
Steps:
To eradicate all prior traces of md configuration, I issue these commands:
mdadm --stop /dev/md/all
which stops.
mdadm --zero-superblock /dev/sd[each drive]2
I went further (after some trouble) and issued
dd if=/dev/zero of=/dev/sd[each drive]2 count=2M
I then issue:
rm /dev/md* /dev/md/*
The ARRAY information is commented out of the config file (mdadm.conf).
On reboot, I see that the devices /dev/md/all, /dev/md/all1, etc. have
reappeared, along /dev/md127, /dev/md_127, and /dev/md_d127.
This is very, very puzzling.
Well, I thought I could work around this. I issued
mdadm --create /dev/md/all
with the same paramters as above. I can use cfdisk and fdisk (either
one) to create two partitions, /dev/md/all1 and /dev/md/all2.
However,
mkfs.reiserfs /dev/md/all1
claims that the /dev/md/all1 has "no such device or address."
ls -l /dev/md/all gives
brw-rw---- 1 root disk 254, 8129 (date) /dev/md/all1
QUESTIONS:
1. If I create a device called /dev/md/all, should I expect that mdadm
will create a device called /dev/md/127, and that mdadm --detail --scan
will report it as /dev/md127 or something similar?
2. How can I completely eradicate all traces of previous work, given
that zero-superblock and dd on the drives that make up the array doesn't
seem to erase previous information?
--
Moshe Yudkowsky * moshe@xxxxxxxxx * www.pobox.com/~moshe
"If you're going to shoot, shoot! Don't talk!"
-- Eli Wallach,"The Good, the Bad, and the Ugly"
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