[CentOS] extend raid volume - new drive
Toby Bluhm
tkb at alltechmedusa.com
Tue Apr 28 12:29:49 UTC 2009
dnk wrote:
> Hi there, I have a system with the following:
>
> # fdisk -l
>
> Disk /dev/sda: 80.0 GB, 80000000000 bytes
> 255 heads, 63 sectors/track, 9726 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
>
> Device Boot Start End Blocks Id System
> /dev/sda1 * 1 13 104391 83 Linux
> /dev/sda2 14 9471 75971385 83 Linux
> /dev/sda3 9472 9726 2048287+ 82 Linux swap /
> Solaris
>
> Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes
> 255 heads, 63 sectors/track, 121601 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
>
> Device Boot Start End Blocks Id System
> /dev/sdb1 * 1 121601 976760001 fd Linux raid
> autodetect
>
>
> Disk /dev/sdd: 1000.2 GB, 1000204886016 bytes
> 255 heads, 63 sectors/track, 121601 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
>
> Device Boot Start End Blocks Id System
> /dev/sdd1 * 1 121601 976760001 fd Linux raid
> autodetect
>
> Disk /dev/md0: 1000.2 GB, 1000202174464 bytes
> 2 heads, 4 sectors/track, 244189984 cylinders
> Units = cylinders of 8 * 512 = 4096 bytes
>
> Disk /dev/md0 doesn't contain a valid partition table
>
>
> Now I just added a new hard drive (sdc).
>
> I was wondering how to go about (if possible) to add this drive to my
> existing partitions with LVM.
>
> Now I never setup this system (Another person had), and if i am
> reading the above right, it appears as though they did not use LVM for
> the raid.
>
> The system has the OS on a standalone drive, the home folder is on the
> two raided drives. I was hoping to extend my home folder to take
> advantage of my new drive.
>
> Recommendations?
WHat size is the new disk? If it's 1GB, you have many options. If not,
there will be trade offs getting it into your system.
If 1G, then
- add disk to md0 for 3 way mirror.
no increase in space, added safety/redundancy, current data kept.
- convert to raid5
increase in space, slight reduction in safety/redundancy, current data kept.
- convert all to LVM
flexible, largest storage, no redundancy, current data kept.
- convert to raid0
fast, largest storage, no redundancy, not flexible as LVM, destroys
current data.
If the third disk in not 1GB, then
- convert to any raid
available space will be dictated by the smallest device/partition,
wastes disk space, same other raid features as above.
- convert all to LVM
flexible, largest storage, no redundancy, current data kept.
- keep md0 as is, add sdc as a separate mount.
easy, not flexible storage, reduced safety/redundancy, current data kept.
- trade for a 1G disk.
--
tkb
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