CentOS - Jul 2009 - raid 1 disks upgrade

Hello all,

I have a machine with 2 SATA 250GB disks which I want to upgrade to 1TB
SATAs

This is the partition structure on both disks:

Disk /dev/sda: 250.0 GB, 250059350016 bytes
255 heads, 63 sectors/track, 30401 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1          25      200781   fd  Linux raid
autodetect
/dev/sda2              26        1971    15631245   fd  Linux raid
autodetect
/dev/sda3            1972       30401   228363975   fd  Linux raid
autodetect

there are 3x RAID1 arrays. 
First is for /boot
Second if for swap
Third is for LVM (contains / and other filesystems)

What is the easiest way to get this upgraded?

I thought that I could maybe dd all the LVM volumes and /boot into
files, setup the new RAID1 arrays on the 1TB disks, and dd everything
back? or is there an easier way?

Regards,
Coert

On Mon, Jul 13, 2009 at 12:13 PM, Coert
Waagmeester<lgroups at waagmeester.co.za> wrote:
>
> I have a machine with 2 SATA 250GB disks which I want to upgrade to 1TB
> SATAs
>
> This is the partition structure on both disks:
>
> Disk /dev/sda: 250.0 GB, 250059350016 bytes
> 255 heads, 63 sectors/track, 30401 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
>
> ? Device Boot ? ? ?Start ? ? ? ? End ? ? ?Blocks ? Id ?System
> /dev/sda1 ? * ? ? ? ? ? 1 ? ? ? ? ?25 ? ? ?200781 ? fd ?Linux raid
> autodetect
> /dev/sda2 ? ? ? ? ? ? ?26 ? ? ? ?1971 ? ?15631245 ? fd ?Linux raid
> autodetect
> /dev/sda3 ? ? ? ? ? ?1972 ? ? ? 30401 ? 228363975 ? fd ?Linux raid
> autodetect
>
> there are 3x RAID1 arrays.
> First is for /boot
> Second if for swap
> Third is for LVM (contains / and other filesystems)
>
> What is the easiest way to get this upgraded?
>
> I thought that I could maybe dd all the LVM volumes and /boot into
> files, setup the new RAID1 arrays on the 1TB disks, and dd everything
> back? or is there an easier way?
>
The software RAID 1 implementation of the kernel allows the array to
be extended. First you replace each old disk with the new 1TB disks
and each time rebuild the array. After this the array is still only
250GB but the partitions are already 1TB in size. Then use the --grow
option of mdadm to increase the array to 1TB. Then it starts rebuilded
the new space. When this is ready you can use the pvextend command to
tell LVM that the PV has grown. Then the new space should be available
in the volume group and you can increase the LV's and the filesystems
inside them.

Regards,
Tim

-- 
Tim Verhoeven - tim.verhoeven.be at gmail.com - 0479 / 88 11 83

Hoping the problem  magically goes away  by ignoring it is the
"microsoft approach to programming" and should never be allowed.
(Linus Torvalds)

Just my two pence;

So just to confirm do you have 3 physical raid 1 arrays you want to
merge into 1? Or are these 3 partitions on a single physical raid
1array;

If its the later I find the easiest way (providing your hardware
supports this) is to set one drive as off line (so you are now in
running in a degraded raid mode) and replace that 250 with a 1TB
drive, then change the mode to online again and it will rebuild the
raid on the 1TB drive from the remaining 250GB drive. Now take the
remaining 250GB disk off line so you are running from the 1TB disk,
replace the 250GB drive with the other 1TB disk and rebuild onto that
one and now you have 2x1TB disks in raid 1?

James ;)

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