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 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 et voila for the first raid5 do the same with the second one Regards > > Also, please note that this is a Dual PIII 1.2 Tualatin. I'm runing > OpenVZ with virtual machines that are not really CPU expensive, but I > would not like to see my processors spending most of their time > computing XORs for the RAID5. > > Any suggestions/tips welcome. > > Regards, > > Ugo > > _______________________________________________ > 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