raid1 not reporting the right size

raid1 not reporting the right size

[gmack]

I'm trying to create a raid1 (mirrored) raid using two 1 Tb disks.
The result is something twice as large as it should be fore mirrored raid.

Any ideas? Linux version 2.6.34

# mkfs.btrfs -d raid1 -m raid1 /dev/sdb1 /dev/sdc1 -L fhome

WARNING! - Btrfs Btrfs v0.19 IS EXPERIMENTAL
WARNING! - see http://btrfs.wiki.kernel.org before using

adding device /dev/sdc1 id 2
fs created label fhome on /dev/sdb1
        nodesize 4096 leafsize 4096 sectorsize 4096 size 1.82TB
Btrfs Btrfs v0.19

# mount /dev/sdb1 /mnt/
# df -h /mnt/
Filesystem            Size  Used Avail Use% Mounted on
/dev/sdb1             1.9T   56K  1.9T   1% /mnt

# btrfs-show
failed to read /dev/sr0
Label: none  uuid: a2aa44b8-3168-480a-a155-d510e05853e7
        Total devices 1 FS bytes used 617.45MB
        devid    1 size 29.33GB used 6.79GB path /dev/sda2

Label: fhome  uuid: 128ddab5-224d-4f45-abc0-6a07d0f63d47
        Total devices 2 FS bytes used 28.00KB
        devid    2 size 931.51GB used 2.01GB path /dev/sdc1
        devid    1 size 931.51GB used 2.03GB path /dev/sdb1

--
Gerhard Mack

gmack@innerfire.net

<>< As a computer I find your faith in technology amusing.

Re: raid1 not reporting the right size

[Chris Ball]

Hi,

   > I'm trying to create a raid1 (mirrored) raid using two 1 Tb
   > disks.  The result is something twice as large as it should be
   > fore mirrored raid.

https://btrfs.wiki.kernel.org/index.php/FAQ#Why_does_df_show_incorrect_free_space_for_my_RAID_volume.3F

-- 
Chris Ball   <cjb@laptop.org>
One Laptop Per Child

Re: raid1 not reporting the right size

[Josef Bacik]

On Thu, May 27, 2010 at 03:43:05PM -0400, gmack@innerfire.net wrote:
> I'm trying to create a raid1 (mirrored) raid using two 1 Tb disks.
> The result is something twice as large as it should be fore mirrored raid.
> 
> Any ideas? Linux version 2.6.34
> 
> # mkfs.btrfs -d raid1 -m raid1 /dev/sdb1 /dev/sdc1 -L fhome
> 
> WARNING! - Btrfs Btrfs v0.19 IS EXPERIMENTAL
> WARNING! - see http://btrfs.wiki.kernel.org before using
> 
> adding device /dev/sdc1 id 2
> fs created label fhome on /dev/sdb1
>         nodesize 4096 leafsize 4096 sectorsize 4096 size 1.82TB
> Btrfs Btrfs v0.19
> 
> # mount /dev/sdb1 /mnt/
> # df -h /mnt/
> Filesystem            Size  Used Avail Use% Mounted on
> /dev/sdb1             1.9T   56K  1.9T   1% /mnt
> 
> # btrfs-show
> failed to read /dev/sr0
> Label: none  uuid: a2aa44b8-3168-480a-a155-d510e05853e7
>         Total devices 1 FS bytes used 617.45MB
>         devid    1 size 29.33GB used 6.79GB path /dev/sda2
> 
> Label: fhome  uuid: 128ddab5-224d-4f45-abc0-6a07d0f63d47
>         Total devices 2 FS bytes used 28.00KB
>         devid    2 size 931.51GB used 2.01GB path /dev/sdc1
>         devid    1 size 931.51GB used 2.03GB path /dev/sdb1
> 

Used will show up as twice the amount that is actually used, instead of looking
like you only have 1/2 the capacity.  Thanks,

Josef

linux 2.6.34 raid1 btrfs weird mounting issue

[gmack]

I had my raid set to mount by uuid but that randomly doesn't work so I 
changed to mounting by the first partition in the raid.. that worked but 
on the next reboot it failed.  Changing the mount to the second partition 
worked until the next reboot when I needed it to change it back to the 
first.  Each change seems to last for one reboot.


# mount /dev/sdb1  /home
mount: wrong fs type, bad option, bad superblock on /dev/sdb1,
       missing codepage or helper program, or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

# mount /dev/sdb1  /home
mount: wrong fs type, bad option, bad superblock on /dev/sdb1,
       missing codepage or helper program, or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

mount /dev/sdc1  /home
(worked)
# btrfs-show
failed to read /dev/sr0
Label: none  uuid: a2aa44b8-3168-480a-a155-d510e05853e7
        Total devices 1 FS bytes used 5.46GB
        devid    1 size 29.33GB used 13.29GB path /dev/sda2

Label: fhome  uuid: 128ddab5-224d-4f45-abc0-6a07d0f63d47
        Total devices 2 FS bytes used 8.24GB
        devid    1 size 931.51GB used 21.03GB path /dev/sdb1
        devid    2 size 931.51GB used 21.01GB path /dev/sdc1


	Gerhard


--
Gerhard Mack

gmack@innerfire.net

<>< As a computer I find your faith in technology amusing.

Re: linux 2.6.34 raid1 btrfs weird mounting issue

[Sebastian 'gonX' Jensen]

On 28 May 2010 20:45,  <gmack@innerfire.net> wrote:
> I had my raid set to mount by uuid but that randomly doesn't work so =
I
> changed to mounting by the first partition in the raid.. that worked =
but
> on the next reboot it failed. =C2=A0Changing the mount to the second =
partition
> worked until the next reboot when I needed it to change it back to th=
e
> first. =C2=A0Each change seems to last for one reboot.
>
>
> # mount /dev/sdb1 =C2=A0/home
> mount: wrong fs type, bad option, bad superblock on /dev/sdb1,
> =C2=A0 =C2=A0 =C2=A0 missing codepage or helper program, or other err=
or
> =C2=A0 =C2=A0 =C2=A0 In some cases useful info is found in syslog - t=
ry
> =C2=A0 =C2=A0 =C2=A0 dmesg | tail =C2=A0or so
>
> # mount /dev/sdb1 =C2=A0/home
> mount: wrong fs type, bad option, bad superblock on /dev/sdb1,
> =C2=A0 =C2=A0 =C2=A0 missing codepage or helper program, or other err=
or
> =C2=A0 =C2=A0 =C2=A0 In some cases useful info is found in syslog - t=
ry
> =C2=A0 =C2=A0 =C2=A0 dmesg | tail =C2=A0or so
>
> mount /dev/sdc1 =C2=A0/home
> (worked)
> # btrfs-show
> failed to read /dev/sr0
> Label: none =C2=A0uuid: a2aa44b8-3168-480a-a155-d510e05853e7
> =C2=A0 =C2=A0 =C2=A0 =C2=A0Total devices 1 FS bytes used 5.46GB
> =C2=A0 =C2=A0 =C2=A0 =C2=A0devid =C2=A0 =C2=A01 size 29.33GB used 13.=
29GB path /dev/sda2
>
> Label: fhome =C2=A0uuid: 128ddab5-224d-4f45-abc0-6a07d0f63d47
> =C2=A0 =C2=A0 =C2=A0 =C2=A0Total devices 2 FS bytes used 8.24GB
> =C2=A0 =C2=A0 =C2=A0 =C2=A0devid =C2=A0 =C2=A01 size 931.51GB used 21=
=2E03GB path /dev/sdb1
> =C2=A0 =C2=A0 =C2=A0 =C2=A0devid =C2=A0 =C2=A02 size 931.51GB used 21=
=2E01GB path /dev/sdc1
>
>
> =C2=A0 =C2=A0 =C2=A0 =C2=A0Gerhard
>
>
> --
> Gerhard Mack
>
> gmack@innerfire.net
>
> <>< As a computer I find your faith in technology amusing.
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs=
" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at =C2=A0http://vger.kernel.org/majordomo-info.ht=
ml
>

Did you check output from dmesg?
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Re: linux 2.6.34 raid1 btrfs weird mounting issue

[Goffredo Baroncelli]

Hi Gerhard

On Friday, May 28, 2010, gmack@innerfire.net wrote:
> I had my raid set to mount by uuid but that randomly doesn't work so I 
> changed to mounting by the first partition in the raid.. that worked but 
> on the next reboot it failed.  Changing the mount to the second partition 
> worked until the next reboot when I needed it to change it back to the 
> first.  Each change seems to last for one reboot.


Do you perform a "scan" before mounting the first time (after a reboot) a 
multivolume btrfs filesystem ?
On the basis of your report it seems no.  

Btrfs requires to know where the components of a multi-volume filesystem are. 
To do that, you have to "scan" the devices, explicitly

	# btrfs scan /dev/sdX1 /dev/sdx2 ...

or implicitly

        # btrfs scan

In the last case the btrfs command scans every block device (even the cdrom 
and/or floppy).

For other information you may want to read this thread which suggests how udev 
can perform the scan.

http://kerneltrap.org/mailarchive/linux-btrfs/2010/4/16/6884594

Regards



> 
> 
> # mount /dev/sdb1  /home
> mount: wrong fs type, bad option, bad superblock on /dev/sdb1,
>        missing codepage or helper program, or other error
>        In some cases useful info is found in syslog - try
>        dmesg | tail  or so
> 
> # mount /dev/sdb1  /home
> mount: wrong fs type, bad option, bad superblock on /dev/sdb1,
>        missing codepage or helper program, or other error
>        In some cases useful info is found in syslog - try
>        dmesg | tail  or so
> 
> mount /dev/sdc1  /home
> (worked)
> # btrfs-show
> failed to read /dev/sr0
> Label: none  uuid: a2aa44b8-3168-480a-a155-d510e05853e7
>         Total devices 1 FS bytes used 5.46GB
>         devid    1 size 29.33GB used 13.29GB path /dev/sda2
> 
> Label: fhome  uuid: 128ddab5-224d-4f45-abc0-6a07d0f63d47
>         Total devices 2 FS bytes used 8.24GB
>         devid    1 size 931.51GB used 21.03GB path /dev/sdb1
>         devid    2 size 931.51GB used 21.01GB path /dev/sdc1
> 
> 
> 	Gerhard
> 
> 
> --
> Gerhard Mack
> 
> gmack@innerfire.net
> 
> <>< As a computer I find your faith in technology amusing.
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 


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