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* RAID1 problem, newbie to RAID
@ 2003-01-20 23:38 J Dalessandro
  2003-01-21  1:03 ` Scott Mcdermott
  0 siblings, 1 reply; 3+ messages in thread
From: J Dalessandro @ 2003-01-20 23:38 UTC (permalink / raw)
  To: linux-raid

I am trying to get RAID1 working on a Debian machine with a 2.4.20 
kernel. I hope I am close, but this is my first attempt at RAID on any 
platform.

I seem to get two out of three partitions. I think my problem is in that 
my "/" partition is mounted, but I'm new to RAID and I'm not sure how to 
fix this issue. Below is my: /proc/mdstat, raidtab, fdisk -l outputs. 
What am I missing here to solve my bungled configuration?

CM:~# cat /proc/mdstat
Personalities : [raid1]
read_ahead 1024 sectors
md0 : active raid1 hda1[0]
       96256 blocks [2/1] [U_]

md1 : active raid1 hda2[0]
       9767424 blocks [2/1] [U_]

unused devices: <none>

CM:~# cat /etc/raidtab
raiddev /dev/md2
         raid-level              1
         nr-raid-disks           2
         nr-spare-disks          0
         chunk-size              32
         persistent-superblock   1
         device                  /dev/hda3
         raid-disk               0
         device                  /dev/hdc3
         failed-disk             1

raiddev /dev/md1
         raid-level              1
         nr-raid-disks           2
         nr-spare-disks          0
         chunk-size              32
         persistent-superblock   1
         device                  /dev/hda2
         raid-disk               0
         device                  /dev/hdc2
         failed-disk             1

raiddev /dev/md0
         raid-level              1
         nr-raid-disks           2
         nr-spare-disks          0
         chunk-size              32
         persistent-superblock   1
         device                  /dev/hda1
         raid-disk               0
         device                  /dev/hdc1
         failed-disk             1

CM:~# df -k
Filesystem           1k-blocks      Used Available Use% Mounted on
/dev/hda3             86437648    480844  81565840   1% /

CM:~# fdisk -l

Disk /dev/hdc: 255 heads, 63 sectors, 12161 cylinders
Units = cylinders of 16065 * 512 bytes

    Device Boot    Start       End    Blocks   Id  System
/dev/hdc1             1        12     96358+  fd  Linux raid autodetect
/dev/hdc2            13      1228   9767520   fd  Linux raid autodetect
/dev/hdc3          1229     12161  87819322+  fd  Linux raid autodetect

Disk /dev/hda: 255 heads, 63 sectors, 12161 cylinders
Units = cylinders of 16065 * 512 bytes

    Device Boot    Start       End    Blocks   Id  System
/dev/hda1   *         1        12     96358+  83  Linux
/dev/hda2            13      1228   9767520   82  Linux swap
/dev/hda3          1229     12161  87819322+  83  Linux
CM:~#


^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: RAID1 problem, newbie to RAID
  2003-01-20 23:38 RAID1 problem, newbie to RAID J Dalessandro
@ 2003-01-21  1:03 ` Scott Mcdermott
  0 siblings, 0 replies; 3+ messages in thread
From: Scott Mcdermott @ 2003-01-21  1:03 UTC (permalink / raw)
  To: linux-raid

J Dalessandro on Mon 20/01 16:38 -0700:
> I seem to get two out of three partitions. I think my problem is in
> that my "/" partition is mounted, but I'm new to RAID and I'm not sure
> how to fix this issue.

You can't have the filesystem mounted from the device you want to make
RAID; you have to boot from something else to do it before mounting it.

Also please realize that when you use persistent-superblock 1, mkraid
will use the last 4k (I think that's how much) for MD information,
overwriting filesystem data there, so you have to resize2fs if you have
existing data, before doing the mkraid.  If you didn't do this, your FS
is now hosed, but maybe you didn't have any data blocks there (after
all, 4k is usually only one filesystem block) and e2fsck will repair it
without data loss.  Using debugfs and dumpe2fs will tell you more
information.

Also, I'm curious why you have the failed disks in your raidtab.

^ permalink raw reply	[flat|nested] 3+ messages in thread

* RE: RAID1 problem, newbie to RAID
@ 2003-01-21 21:57 Cress, Andrew R
  0 siblings, 0 replies; 3+ messages in thread
From: Cress, Andrew R @ 2003-01-21 21:57 UTC (permalink / raw)
  To: 'J Dalessandro', linux-raid

The way to do this is to build the raid on the second disk, and mark the
first one (where you are currently mounted) as the failed disk in raidtab.
You have the raidtab set to use the first disk as the one to format for
raid, so it is busy.

The steps to build a software RAID from an existing Linux install are
outlined at 
  http://www.ibiblio.org/pub/Linux/docs/HOWTO/Software-RAID-HOWTO (section
4.12 & ff)
or
  http://scsirastools.sourceforge.net/docs/UserGuide (section 4.0)

Andy

-----Original Message-----
From: J Dalessandro [mailto:joe@nan0.com] 
Sent: Monday, January 20, 2003 6:39 PM
To: linux-raid@vger.kernel.org
Subject: RAID1 problem, newbie to RAID


I am trying to get RAID1 working on a Debian machine with a 2.4.20 
kernel. I hope I am close, but this is my first attempt at RAID on any 
platform.

I seem to get two out of three partitions. I think my problem is in that 
my "/" partition is mounted, but I'm new to RAID and I'm not sure how to 
fix this issue. Below is my: /proc/mdstat, raidtab, fdisk -l outputs. 
What am I missing here to solve my bungled configuration?

CM:~# cat /proc/mdstat
Personalities : [raid1]
read_ahead 1024 sectors
md0 : active raid1 hda1[0]
       96256 blocks [2/1] [U_]

md1 : active raid1 hda2[0]
       9767424 blocks [2/1] [U_]

unused devices: <none>

CM:~# cat /etc/raidtab
raiddev /dev/md2
         raid-level              1
         nr-raid-disks           2
         nr-spare-disks          0
         chunk-size              32
         persistent-superblock   1
         device                  /dev/hda3
         raid-disk               0
         device                  /dev/hdc3
         failed-disk             1

raiddev /dev/md1
         raid-level              1
         nr-raid-disks           2
         nr-spare-disks          0
         chunk-size              32
         persistent-superblock   1
         device                  /dev/hda2
         raid-disk               0
         device                  /dev/hdc2
         failed-disk             1

raiddev /dev/md0
         raid-level              1
         nr-raid-disks           2
         nr-spare-disks          0
         chunk-size              32
         persistent-superblock   1
         device                  /dev/hda1
         raid-disk               0
         device                  /dev/hdc1
         failed-disk             1
[...]

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2003-01-21 21:57 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2003-01-20 23:38 RAID1 problem, newbie to RAID J Dalessandro
2003-01-21  1:03 ` Scott Mcdermott
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2003-01-21 21:57 Cress, Andrew R

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