Brett Serkez spake the following on 4/1/2007 3:04 PM:
I performed a test install of CentOS Beta 5 on a system with two ~60 GB drives. When installing CentOS 4 on this system, I normally work thru setting up Software RAID with identically sized partitions on each drive.
For my test, the CentOS installer only presented a single drive. I took the default of letting it do what it wanted. After looking over the system I have verified that /boot is using DMRAID, but it isn't not clear if the balance of the drive for the root file system is using both drives or not, I think it might be.
Using fdisk, I can see both disks are carved out identically:
Device Boot Start End Blocks Id System /dev/hda1 * 1 13 104391 83 Linux /dev/hda2 14 7297 58508730 8e Linux LVM
/dev/hdd1 * 1 13 104391 83 Linux /dev/hdd2 14 7297 58508730 8e Linux LVM
Using dmraid it *looks* like the drives are mirrored in total?
dmraid -r -D /dev/hda: pdc, "pdc_bacfgfjaf", mirror, ok, 117231345 sectors, data@ 0 /dev/hdd: pdc, "pdc_bacfgfjaf", mirror, ok, 117231345 sectors, data@ 0
But then using df it is less obvious:
df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/VolGroup00-LogVol00 54G 1009M 50G 2% / /dev/mapper/pdc_bacfgfjafp1 99M 11M 83M 12% /boot tmpfs 125M 0 125M 0% /dev/shm
pvs shows VolGroup00 as using pdc_bacfgfjafp2:
PV VG Fmt Attr PSize PFree /dev/mapper/pdc_bacfgfjafp2 VolGroup00 lvm2 a- 55.78G 32.00M
which is RAID1??????
Seems to be:
dmraid -s *** Active Set name : pdc_bacfgfjaf size : 117231232 stride : 128 type : mirror status : ok subsets: 0 devs : 2 spares : 0
Am I properly understanding that by default, CentOS 5 is creating a full drive mirrored RAID? Then for other than the boot partition, it is laying LVM over this mirrored RAID, presumably to allow adjustments later?
Thank you in advance,
Brett
Does the board have an onboard fakeraid? I think that is what DMRAID does. It supports some of the fakeraid controllers, although it is much less mature than plain software raid.