raid fun in debian (sarge)
I have 2 120GB IDE drives in the second IDE controller of a
P4 debian box that I would like to set up as a raid1 array. Using
info from the following links,
http://www.linuxdevcenter.com/pub/a/linux/2002/12/05/RAID.html
http://en.tldp.org/HOWTO/Software-RAID-HOWTO-5.html
I do
<Note: I partitioned /dev/hd{c,d} using fdisk, but it seems that was
not needed>
laurel:/home/debian# mdadm -Cv /dev/md0 -l1 -n2 /dev/hd{c,d}1
mdadm: /dev/hdd1 appears to contain a reiserfs file system
size = 117210208K
mdadm: size set to 117210112K
Continue creating array? y
mdadm: array /dev/md0 started.
laurel:/home/debian#urel:/home/debian# mdadm --detail --scan
ARRAY /dev/md0 level=raid1 num-devices=2
UUID=a9ad3f4b:ec821a50:da01bd3e:1817087d
devices=/dev/hdc1,/dev/hdd1
laurel:/home/debian#
laurel:/home/debian# mdadm -E /dev/hdc1
/dev/hdc1:
Magic : a92b4efc
Version : 00.90.00
UUID : a9ad3f4b:ec821a50:da01bd3e:1817087d
Creation Time : Fri Mar 26 05:01:20 2004
Raid Level : raid1
Device Size : 117210112 (111.78 GiB 120.02 GB)
Raid Devices : 2
Total Devices : 2
Preferred Minor : 0
Update Time : Fri Mar 26 05:01:20 2004
State : dirty, no-errors
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
Checksum : b937ea96 - correct
Events : 0.1
Number Major Minor RaidDevice State
this 0 22 1 0 active sync /dev/hdc1
0 0 22 1 0 active sync /dev/hdc1
1 1 22 65 1 active sync /dev/hdd1
laurel:/home/debian#
# fdisk /dev/md0
[...]
Disk /dev/md0: 120.0 GB, 120023154688 bytes
2 heads, 4 sectors/track, 29302528 cylinders
Units = cylinders of 8 * 512 = 4096 bytes
Device Boot Start End Blocks Id System
/dev/md0p1 1 29302528 117210110 83 Linux
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: Re-reading the partition table failed with error 22: Invalid argument.
The kernel still uses the old table.
The new table will be used at the next reboot.
Syncing disks.
laurel:/home/debian#
<after rebooting...>
laurel:/# mount -o rw /dev/md0 /mnt
laurel:/# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/hda1 18G 3.5G 14G 21% /
tmpfs 252M 0 252M 0% /dev/shm
/dev/md0 112G 177M 112G 1% /mnt
laurel:/#
But, when I try to write something to /mnt, I am told it is a
read-only filesystem:
laurel:/# cd /mnt
laurel:/mnt# touch m
touch: cannot touch `m': Read-only file system
laurel:/mnt#
What am I missing here?
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