[CentOS] Re: RAID, LVM, extra disks...
aspineux at gmail.com
Thu Nov 29 16:14:22 UTC 2007
On Nov 29, 2007 4:21 PM, Ugo Bellavance <ugob at lubik.ca> wrote:
> Alain Spineux wrote:
> > On Nov 29, 2007 6:59 AM, Ugo Bellavance <ugob at lubik.ca> wrote:
> >> Hi,
> >> This is my current config:
> >> /dev/md0 -> 200 MB -> sda1 + sdd1 -> /boot
> >> /dev/md1 -> 36 GB -> sda2 + sdd2 -> form VolGroup00 with md2
> >> /dev/md2 -> 18 GB -> sdb1 + sde1 -> form VolGroup00 with md1
> >> sda,sdd -> 36 GB 10k SCSI HDDs
> >> sdb,sde -> 18 GB 10k SCSI HDDs
> >> I have added 2 36 GB 10K SCSI drives in it, they are detected as sdc and
> >> sdf.
> >> What should I do if I want to optimize disk space?
> >> The simplest solution would be to create /dev/md3 out of sdc1 and sdf1,
> >> and add it to the VG, and increase the size of my /vz logical volume.
> >> However, if I could convert that to a RAID5 (it could be possible to
> >> re-install, but I would rather not), I could have 6 drives in RAID5, so
> >> I'd have 5x36 GB (180) of space available total, instead of 3*36 (108).
> > 180, you mean 2 X 5x18
> Oh, I just realized I have 2X18 and 4X36. I have 2 other 36 GB HDD
> here. Maybe I could have a 6x36 RAID5 this way. Does it matter if I
drop the 2x18, to drop the 2x18 complexity,
or keep them in mirroring, and maybe on another VG,
to backup/store more critical data
> have 4 HDD that are 10K and 2 7200 rpm?
> What about raid 6? I don't think I need fault tolerance for 2 HDD
raid 6! more disk, more problems! use it as hotspare instead.
> > Yes and without rebooting :-)
> > - break the 36GB mirror (using mdadm, faile /dev/sdd2, and then remove it),
> > - break the 18GB mirror (using mdadm, faile /dev/sde1, and then remove it),
> > - create sd[cf] of 200Mb, 18G, 18G (the 200Mb is useless but to
> > keep the same partitioning schema)
> > - create a _degraded_ raid5 with sd[cfd]2 sde1 named /dev/mdX
> > - vgextend your VolGroup00 to use this new partition.
> > # pvcreate /dev/mdX
> > # vgextend VolGroup00 /dev/mdX
> > - then move all PE on md1 to mdX
> > # pvmove /dev/md1/dev/mdX
> > - then remove md1 from the VG
> > # vgreduce VolGroup00 /dev/md1
> > - now you dont need md1 anymore, stop it (sorry I'm less skilled with
> > mdadm command, without manual page )
> > - now add /dev/sda2 to your _degraded_ raid 5
> CentOS mailing list
> CentOS at centos.org
aspineux gmail com
May the sources be with you
More information about the CentOS