Increasing Space in Software Raid

[nilesh vaghela]

I suggest you backup every thing first.

A single mistake will be big trouble.

On Jan 31, 2008 4:00 AM, John J. Culkin <culkinj3 at scranton.edu> wrote:
> If I have 2 disk in a software raid, should I use "dd"  to make sure
> that they have the same Master Boot Record?
>
>
> -- John C.
>
> Broekman, Maarten wrote:
> > 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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-- 
Nilesh Vaghela
ElectroMech
Redhat Channel Partner and Training Partner
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