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? No > > What about raid 6? I don't think I need fault tolerance for 2 HDD > failures... 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][123] 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 > http://lists.centos.org/mailman/listinfo/centos > -- Alain Spineux aspineux gmail com May the sources be with you