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 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 failures... > > 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