[SOLVED] Increase no of RAID device

eldo · 11-17-2009, 11:44 PM

Hi,

I have created a RAID meta device, with two raid devices. I need to increase the no of devices, then only I can add new hard drive.

mostlyharmless · 11-18-2009, 10:54 AM

Depends on what kind of RAID, hardware, software, fakeraid. For mdadm (software RAID), the answer is :

Quoted from the man for mdadm (http://linux.die.net/man/8/mdadm) use the -G option to grow the array

Quote:

n, --raid-devices=

Specify the number of active devices in the array. This, plus the number of spare devices (see below) must equal the number of component-devices (including "missing" devices) that are listed on the command line for --create. Setting a value of 1 is probably a mistake and so requires that --force be specified first. A value of 1 will then be allowed for linear, multipath, raid0 and raid1. It is never allowed for raid4 or raid5.
This number can only be changed using --grow for RAID1 arrays, and only on kernels which provide necessary support.

Usually you have to remake the array entirely, destroying the previous one.

eldo · 11-18-2009, 10:57 AM

Quote:

Originally Posted by mostlyharmless

Depends on what kind of RAID, hardware, software, fakeraid. For mdadm (software RAID), the answer is :

Quoted from the man for mdadm (http://linux.die.net/man/8/mdadm)use the -G option to grow the array

Usually you have to remake the array entirely, destroying the previous one.

if I need to add a new raid device as a hot spare or how can i add a hot spare to a existing meta device

mostlyharmless · 11-18-2009, 12:19 PM

Again, you need to have specified the number of total spares in your initial --create if you used mdadm. If you have specified a spare or failed drive and you need to add a new spare back then use something like

mdadm /dev/md0 --add /dev/sda1 --fail /dev/sdb1 --remove /dev/sdb1

for example to fail sdb1, remove it and add sda1. Spares automatically get used as needed if active drives fail.

BTW, don't make duplicate threads: http://www.linuxquestions.org/questi...device-769985/