On Thu, 29 Mar 2012 18:47:14 +0000 "Paramasivam, Meenakshisundaram"
<mparamas@xxxxxxxxx> wrote:
>
> Clarification:
> >>should I do new array creation
> I meant running newfs on assembled 12 TB array, and restore data from backup, to resolve "df" reporting problem.
I would suggest asking on
linux-ext4@xxxxxxxxxxxxxxx
be sure to give lots of details - kernel version etc.
It would be worth running
fsck -n /dev/md2
first and see if it reports anything strange.
Maybe just a fsck will fix it.
NeilBrown
>
> ________________________________________
> From: Paramasivam, Meenakshisundaram
> Sent: Thursday, March 29, 2012 1:33 PM
> To: NeilBrown
> Cc: linux-raid@xxxxxxxxxxxxxxx
> Subject: RE: mdadm raid6 recovery status
>
> Good news: Got ALL of our data back. [Actually it was 4.96TB not 7TB].
> mdadm is a good one.
>
> Bad news: "df" is reporting wrong, while "du" is showing full size.
> # df -kl /myarray
> Filesystem 1K-blocks Used Available Use% Mounted on
> /dev/md2 11537161976 162432 10950945196 1% /myarray
> # du -sk /myarray
> 5326133556 /myarray
> #
>
> I never looked into du or looked in depth of the files & folders and simply got mislead by reported "df" usage; data was there all along. We definitely want "df" for the array's filesystem (ext3) to report right.
>
> Now that we are backing up all of the data (at 400 Mbps) over network, I want to know if "df" reporting can be fixed easily or should I do new array creation and restore data from backup.
>
> We are ordering a new RAID card, just to be on safer side.
>
> Sundar
>
> ________________________________________
> From: NeilBrown [neilb@xxxxxxx]
> Sent: Wednesday, March 28, 2012 7:27 PM
> To: Paramasivam, Meenakshisundaram
> Cc: linux-raid@xxxxxxxxxxxxxxx
> Subject: Re: mdadm raid6 recovery status
>
> On Wed, 28 Mar 2012 12:49:18 +0000 "Paramasivam, Meenakshisundaram"
> <mparamas@xxxxxxxxx> wrote:
>
> > [root@in-rady-neuro9 ~]# df -kl /myarray
> > Filesystem 1K-blocks Used Available Use% Mounted on
> > /dev/md2 11537161976 162432 10950945196 1% /myarray
> > Should be 7TB of used space.
>
> This is bad. Something has happened to your filesystem.
> It is almost as though someone ran "mkfs" on the array.
> I don't know much about recovery after such an action, but I doubt you
> will get much back.
>
> >
> > [root@in-rady-neuro9 ~]# cat /proc/partitions
> > major minor #blocks name
> >
> > 8 0 438960128 sda
> > 8 1 512000 sda1
> > 8 2 51200000 sda2
> > 8 3 387247104 sda3
> > 8 16 1953514584 sdb
> > 8 32 1953514584 sdc
> > 8 48 1953514584 sdd
> > 8 64 1953514584 sde
> > 8 80 1953514584 sdf
> > 8 96 1953514584 sdg
> > 8 112 1953514584 sdh
> > 8 128 1953514584 sdi
> > 253 0 346226688 dm-0
> > 253 1 40992768 dm-1
>
> No md2 ???
>
> >
> > sd[b-i] are raid devices
> >
> > [root@in-rady-neuro9 ~]# mdadm --detail /dev/md2
> > /dev/md2:
> > Version : 0.90
> > Creation Time : Fri Dec 16 17:56:14 2011
> > Raid Level : raid6
> > Array Size : 11721086976 (11178.10 GiB 12002.39 GB)
> > Used Dev Size : 1953514496 (1863.02 GiB 2000.40 GB) <<<====== Wrong! Should be 7TB of used array space.
>
> "Used Dev Size" isn't "how much of the array is used by the filesystem" -
> mdadm doesn't know anything about filesystems.
> It is "How much of each individual device is used by the array", which is
> usually a little less than the size of the smallest device.
> So 2TB is correct here.
>
>
> NeilBrown
>
>
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