From mboxrd@z Thu Jan  1 00:00:00 1970
From: "TJ Harrell" <systemloc@earthlink.net>
Subject: raidreconf won't resize a RAID 5 array. Can it be done with mkraid -f ?
Date: Mon, 17 May 2004 11:08:53 -0400
Sender: linux-raid-owner@vger.kernel.org
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I have a raid 5 array consisting of 3 disks. The smallest disk is 195191168
blocks. The array only uses 172551296 blocks from each device. Numbers ar
from output of mdadm. I would like to grow the array to the largest
posssible size. I tried doing a raidreconf using identical settings in
raidtab.old and raidtab.new, and it said the size would remain unchanged
when it asked for confirmation. Is there a way to tweak it to do what I
want, or could I just mkraid -f the existing array? I'm afraid if I just do
a mkraid -f it will fubar the old array by laying out parity info
differently or something since the size of the array will be different.

Raidtab:
raiddev /dev/md0
   raid-level      linear
   nr-raid-disks      3
   persistent-superblock   1
   chunk-size      128

device      /dev/hdk1
raid-disk   0
device      /dev/hdi1
raid-disk   1
device      /dev/hda3
raid-disk   2

raiddev /dev/md1
   raid-level      5
   nr-raid-disks      3
   persistent-superblock   1
   chunk-size      64

device      /dev/hdg1
raid-disk   0
device      /dev/md0
failed-disk 1
device      /dev/hdc1
raid-disk   2


Output of "raidreconf -o /etc/raidtab -n /etc/raidtab.new -m /dev/md1"

Working with device /dev/md1
Parsing /etc/raidtab
Parsing /etc/raidtab.new
Size of old array: 1171815940 blocks,  Size of new array: 1171815940 blocks
Old raid-disk 0 has 3052474 chunks, 195358336 blocks
Old raid-disk 1 has 3049861 chunks, 195191104 blocks
Old raid-disk 2 has 3052474 chunks, 195358336 blocks
New raid-disk 0 has 3052474 chunks, 195358336 blocks
New raid-disk 1 has 3049861 chunks, 195191104 blocks
New raid-disk 2 has 3052474 chunks, 195358336 blocks
Using 64 Kbyte blocks to move from 64 Kbyte chunks to 64 Kbyte chunks.
Detected 418432 KB of physical memory in system
A maximum of 1394 outstanding requests is allowed
---------------------------------------------------
I will convert your old device /dev/md1 of 6102335 blocks
to a new device /dev/md1 of same size
using a block-size of 64 KB
Is this what you want? (yes/no): no