On Thu, 14 Jun 2007, Rich Walker wrote:
Justin Piszcz <jpiszcz@xxxxxxxxxxxxxxx> writes:
On Thu, 14 Jun 2007, Rich Walker wrote:
[snip]
The array is used as a single PV/VG for LVM.
What I want to do is to
(a) reduce the PV/VG so it would fit in 160*3 rather than 160*4
(b) remove the last 160GB drive, (hdi), taking the array from 4+1 to 4+0
(c) rearrange the array from 4+0 to 3+1
(d) grow the array to 250*3
(e) enlarge the PV/VG again.
I would think that
mdadm --grow --raid-devices=4 -z max /dev/md1 /dev/hdg2 /dev/hde2 /dev/sda2 /dev/hdk2
would do steps (b),(c),(d) in one go - is this correct?
The linux kernel version running is 2.6.21.3 SMP.
As far as I know you cannot shrink any md raid in Linux.
Justin.
Step (c) shrinks the array, which would be a problem.
But the mdadm command given *should* actually grow the array (from 640GB
to 750GB) whilst reducing the number of disks...
Is this likely to work?
mdadm says:
thoth:/--# mdadm --grow --help
Usage: mdadm --grow device options
This usage causes mdadm to attempt to reconfigure a running array.
This is only possibly if the kernel being used supports a particular
reconfiguration. This version only supports changing the number of
devices in a RAID1, and changing the active size of all devices in
a RAID1/4/5/6.
Options that are valid with the grow (-G --grow) mode are:
--size= -z : Change the active size of devices in an array.
: This is useful if all devices have been replaced
: with larger devices.
--raid-disks= -n : Change the number of active devices in a RAID1
: array.
thoth:/--# mdadm -V
mdadm - v2.5.6 - 9 November 2006
thoth:/--#
which makes me think it wouldn't...
cheers, Rich.
--
rich walker | Shadow Robot Company | rw@xxxxxxxxxxxxx
technical director 251 Liverpool Road |
need a Hand? London N1 1LX | +UK 20 7700 2487
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You can try it, otherwise grab the latest version of mdadm and go ahead
and grow it. I have grown a 1.8TB array to 3.3TB and it was a pretty old
version of mdadm.
Justin.
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