Re: mdadm doesn't wont to grow - help please

On Mon, 14 May 2012 15:49:53 +0200 Sergiusz Brzeziński
[off-list ref] wrote:

Hi,

I would like to grow the RAID1.

- Raid1 size has about 50GB
- two HD partition (sda2, sdb2) have about 80GB+ (each)

I do:

# mdadm --grow /dev/md0 --size=max

and I get the info, that the new size is 50GB. And I wonder: why not 80GB? The 
size doesn't change! If I try to force size (--size=xxxxx), I get the message 
that there is no space.

What did I wrong?

Probably used an ancient version of mdadm - more than a couple of months
old :-)

If you 
  for i in /sys/block/md0/md/dev*/size
  do echo 0 > $i
  done
then try again it might work better.

Newer mdadm (since May 2011) do this for you.

If you look at the "mdadm -E /dev/sda2" output before and after you will
notice that "Avail Dev Size" changes.

You can achieve the same effect by stopping the array, the assembling it
with --update=devicesize

  mdadm --stop /dev/md0
  mdadm --assemble /dev/md0 --update=devicesize /dev/sd[ab]2
  mdadm --grow /dev/md0 --size=max

NeilBrown

Bellow some facts about my configuration.

Please help.

Thank You in advance

Sergiusz Brzeziński
-----------------------------------------------

# mdadm --detail /dev/md0

/dev/md0:
         Version : 1.2
   Creation Time : Wed Mar 30 07:25:47 2011
      Raid Level : raid1
      Array Size : 52427776 (50.00 GiB 53.69 GB)
   Used Dev Size : 52427776 (50.00 GiB 53.69 GB)
    Raid Devices : 2
   Total Devices : 2
     Persistence : Superblock is persistent

     Update Time : Mon May 14 09:16:16 2012
           State : clean
  Active Devices : 2
Working Devices : 2
  Failed Devices : 0
   Spare Devices : 0

            Name : linux-uo1f.site:1
            UUID : 603ab02b:f8e9c2b9:863ce780:7f8dfca7
          Events : 5472151

     Number   Major   Minor   RaidDevice State
        2       8        2        0      active sync   /dev/sda2
        4       8       18        1      active sync   /dev/sdb2



# cat /proc/mdstat

Personalities : [raid1]
md0 : active raid1 sda2[2] sdb2[4]
       52427776 blocks super 1.2 [2/2] [UU]

unused devices: <none>


# fdisk /dev/sdb

Disk /dev/sdb: 320.1 GB, 320072933376 bytes
255 heads, 63 sectors/track, 38913 cylinders, total 625142448 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0008f6dc

    Device Boot      Start         End      Blocks   Id  System
/dev/sdb1   *        2048      208895      103424   83  Linux
/dev/sdb2          208896   625142447   312466776   fd  Linux raid autodetect


# fdisk /dev/sda

Disk /dev/sda: 90.0 GB, 90028302336 bytes
255 heads, 63 sectors/track, 10945 cylinders, total 175836528 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x08e607c5

    Device Boot      Start         End      Blocks   Id  System
/dev/sda1            2048      208895      103424   83  Linux
/dev/sda2          208896   175836527    87813816   fd  Linux raid autodetect
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