tech-kern archive

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Old Index]

Re: Setting up raid correctly



On 24.02.2013 17:15, Manuel Bouyer wrote:
On Sun, Feb 24, 2013 at 05:36:20PM +0000, Philip Mueller wrote:
On 24.02.2013 16:11, Manuel Bouyer wrote:
On Sun, Feb 24, 2013 at 05:00:07PM +0000, Philip Mueller wrote:
If I partition wd3 single, then I can't setup a raid1 on it.
Because:
spectre# dd if=/dev/zero of=/dev/wd3d
^C8457+0 records in
8456+0 records out
4329472 bytes transferred in 3.467 secs (1248766 bytes/sec)
spectre#gpt show wd3
        start        size  index  contents
            0  3907029168
spectre#gpt create wd3
spectre# gpt add -t ffs wd3
You didn't understand what I wrote. You have to create the partition on wd3
*after* setting up the raid1 and creating the filesystem on it.
The start of the partition on wd3 has to match the location of the ffs
on raid1, shifted by the raid1 metadata, which, I think, is 128 sectors.
Also, you may have to create a raid-type partition on wd3 so that
the partition table on wd3 and the raid1 metadata don't overwrite each other.
This means you'll have 2 overlapping partitions on wd3, one to be used by
raid1 and another one to be used to mount the ffs.

Ok, this is a little much for me.
Can we take this step by step?
1.) undo all configurations
spectre# raidctl -uv raid1
spectre# gpt destroy wd3d
spectre# dd if=/dev/zero of=/dev/wd3
^C408832+0 records in
408831+0 records out
209321472 bytes transferred in 5.371 secs (38972532 bytes/sec)
I think you createed a 209321472 byte regular file /dev/wd3 here,
you didn't clear the wd3 partition table as intended. To write to
the drive, use /dev/wd3d.
Oh Sorry, thats right.
dd if=/dev/zero of=/dev/wd3d
^C7769+0 records in
7768+0 records out
3977216 bytes transferred in 3.081 secs (1290884 bytes/sec)

1.) wd3 is empty, now create raid1 on empty wd3
spectre# raidctl -C /etc/raid1.conf raid1
spectre# label=`date +%Y%m%d%H%M`
spectre# raidctl -I $label raid1
spectre# raidctl -i raid1
Initiating re-write of parity

Is this right so?
No, I think you first have to create a partition of type raid on wd3,
instead of using the whole disk. If your disk is less than 2TB, it may
be easier to use disklabel instead of gpt.

I want to use gpt, if possible, my size is 2TB
How do we create a raid partition, like:
spectre# gpt show wd3d
       start        size  index  contents
           0  3907029168
spectre# gpt create wd3d
spectre# gpt add -t gpt wd3d
usage: gpt add [-b lba] [-i index] [-s lba] [-t type] device ...
spectre# gpt add -t raid wd3d
Partition added, use:
        dkctl wd3d addwedge <wedgename> 34 3907029101 <type>
to create a wedge for it

And now should I dkctl wd3d and copy dkX in my raid1.conf or should I use wd3d?

Home | Main Index | Thread Index | Old Index