On Fri, 30 Mar 2012 21:22:34 +0000 "Paramasivam, Meenakshisundaram" <mparamas@xxxxxxxxx> wrote: > > Thanks. Is it safe to fsck -n (and then fsck -y) on /dev/md2 when sdg is just added to md2 and is in "spare rebulding" status and recovery is only at 4% completed? BTW, we got all of the data backed up. It is certainly safe to "fsck -n" while there is a spare rebuilding. Each process will slow down the other but that shouldn't be a problem. I would never say that "fsck -y" is safe without seeing the output for "fsck -n" however the rebuilding the spare should affect the safety of "fsck -y". And it is always nice to hear that people have their data safe - thanks. NeilBrown > > Background: > When we assembled md2 we forced rest of the drives and did not include this drive. After 24 hrs, when I tried to assemble all of the drives into md2, I got "md: kicking non-fresh sdg from array!" message through dmesg, and was removed from md2 (through mdadm --detail). I just did: > # mdadm /dev/md2 --add /dev/sdg > mdadm: re-added /dev/sdg > > Sundar > > ________________________________________ > From: NeilBrown [neilb@xxxxxxx] > Sent: Thursday, March 29, 2012 3:41 PM > To: Paramasivam, Meenakshisundaram > Cc: linux-raid@xxxxxxxxxxxxxxx > Subject: Re: mdadm raid6 recovery status > > 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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