Increasing Space in Software Raid

[Broekman, Maarten]

If the disks are hotswap capable, you won't need a restart.  If the
disks are not hotswap capable, then you'll need to shut down the system
to replace them.

The best thing would be to recreate the partitions exactly the same on
the new disks first to make sure everything is still working fine.  Then
increase the size of the partitions through fdisk and expand the
filesystem with resize2fs.

Maarten Broekman

-----Original Message-----
From: redhat-list-bounces at redhat.com
[mailto:redhat-list-bounces at redhat.com] On Behalf Of John J. Culkin
Sent: Wednesday, January 30, 2008 10:44 AM
To: General Red Hat Linux discussion list
Subject: Re: Increasing Space in Software Raid

Thanks for the replys

Isn't it a little more complicated then that. I would have to make 
partitions on the new device and then I would have to expand then later

Let me see if I can get a little Betty Crocker recipe here so that we 
are all on the same page

#Fail on device
mdadm --fail /dev/sda1
#Remove the failed drive and then replace it with a larger disk
# mount the disk and format it (would I need a restart in there?)
# Here is where it gets a little tricky for me
# I think I need to make matching partitions on the larger device so 
that I can bring it into the RAIDs (one for /boot, one for / root)
#once that is rebuild I will break the raid again so that I can remove 
the remaining smaller disk
#I will then insert the new disk and mout and formate it
# before I bring the new disk into the raid I will want to grow the size

of the / root raid - this will also mean that I will have to grow its 
partition - any tips on that?

Am I missing anything?

-- John C.

Broekman, Maarten wrote:
> The easiest way would be to break the mirror. Replace the non-live
> device with the new drive.  Make a new metadevice with the new device.
> Copy the data.  Remove the last old device and put in the second new
> device.  Then re-mirror.
>
> To make life easier you might want to use LVM also rather than raw
> metadevices on the new devices.
>
> Maarten Broekman
>
> -----Original Message-----
> From: redhat-list-bounces at redhat.com
> [mailto:redhat-list-bounces at redhat.com] On Behalf Of
> culkinj3 at scranton.edu
> Sent: Tuesday, January 29, 2008 9:38 PM
> To: redhat-list at redhat.com
> Subject: Increasing Space in Software Raid
>
> Hello
>
> I have a server running RHEL 4 and it has a software Raid (1) of 2 250
> gb Sata disks. I want to upgrade this to two 750 gb disks in a Raid 1
> configuration. There is not another SATA slot available. 
>
> Here is some more information
>
> # df -ah
> /dev/md1              229G  196G   21G  91% /
> none                     0     0     0   -  /proc
> none                     0     0     0   -  /sys
> none                     0     0     0   -  /dev/pts
> usbfs                    0     0     0   -  /proc/bus/usb
> /dev/md0               99M   11M   83M  12% /boot
> none                  505M     0  505M   0% /dev/shm
> none                     0     0     0   -  /proc/sys/fs/binfmt_misc
> automount(pid2042)       0     0     0   -  /var/autofs/bacula
> /dev/sdc1             451G  340G   88G  80% /mnt/usb
> #
> cat /proc/mdstat
> Personalities : [raid1]
> md1 : active raid1 sda3[0]
>       242983040 blocks [2/1] [U_]
>
> md0 : active raid1 sda1[0]
>       104320 blocks [2/1] [U_]
>
> unused devices: <none>
>
>
> # cat /etc/fstab
> /dev/md1                /                       ext3    defaults
> 1 1
> /dev/md0                /boot                   ext3    defaults
> 1 2
> none                    /dev/pts                devpts  gid=5,mode=620
> 0 0
> none                    /dev/shm                tmpfs   defaults
> 0 0
> none                    /proc                   proc    defaults
> 0 0
> none                    /sys                    sysfs   defaults
> 0 0
> LABEL=SWAP-sdb2         swap                    swap    defaults
> 0 0
> LABEL=SWAP-sda2         swap                    swap    defaults
> 0 0
> /dev/sdc1               /mnt/usb                ext3    defaults
> 0 0
>
>
> Any suggestions/tips?
>
> -- John C.
>
>   

-- 
John J. Culkin			Systems Administrator
John.Culkin at Scranton.edu	The University of Scranton
Phone: (570) 941-7665

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