Alain Spineux wrote:
On Nov 29, 2007 6:59 AM, Ugo Bellavance <ugob@xxxxxxxx> 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
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