Hi,
I am trying to create a 10 drive raid6 array. OS is Centos 5.3 (64 Bit)
All 10 drives are 2T in size.
device sd{a,b,c,d,e,f} are on my motherboard
device sd{i,j,k,l} are on a pci express areca card (relevant lspci info below)
#lspci
06:0e.0 RAID bus controller: Areca Technology Corp. ARC-1210 4-Port PCI-Express to SATA RAID Controller
The controller is set to JBOD the drives.
All drives have the same partition size
# fdisk -l
Disk /dev/sda: 2000.3 GB, 2000398934016 bytes
255 heads, 63 sectors/track, 243201 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sda1 1 243201 1953512001 83 Linux
....
I go about creating the array as follows
# mdadm --create --verbose /dev/md3 --level=6 --raid-devices=10 /dev/sda1 /dev/sdb1 /dev/sdc1 /dev/sdd1 /dev/sde1 /dev/sdf1 /dev/sdi1 /dev/sdj1 /dev/sdk1 /dev/sdl1
mdadm: layout defaults to left-symmetric
mdadm: chunk size defaults to 64K
mdadm: size set to 1953511936K
Continue creating array?
As you can see mdadm sets the size to 1.9T. Looking around there was this limitation on older versions of mdadm if they are the 32 bit version. I am using the 64 bit most up to date version from Centos.
If I go ahead and say yes create the array, mdadm says the following (I have zeroed the drives before adding them and creating the array)
# mdadm --detail /dev/md3
/dev/md3:
Version : 0.90
Creation Time : Thu Sep 24 23:48:32 2009
Raid Level : raid6
Array Size : 15628095488 (14904.11 GiB 16003.17 GB)
Used Dev Size : 1953511936 (1863.01 GiB 2000.40 GB)
Raid Devices : 10
Total Devices : 10
Preferred Minor : 3
Persistence : Superblock is persistent
Update Time : Thu Sep 24 23:48:32 2009
State : clean, resyncing
Active Devices : 10
Working Devices : 10
Failed Devices : 0
Spare Devices : 0
Chunk Size : 64K
Rebuild Status : 0% complete
UUID : cfa565db:4d0e07ca:b4d87a59:6e96cb06
Events : 0.1
Number Major Minor RaidDevice State
0 8 1 0 active sync /dev/sda1
1 8 17 1 active sync /dev/sdb1
2 8 33 2 active sync /dev/sdc1
3 8 49 3 active sync /dev/sdd1
4 8 65 4 active sync /dev/sde1
5 8 81 5 active sync /dev/sdf1
6 8 129 6 active sync /dev/sdi1
7 8 145 7 active sync /dev/sdj1
8 8 161 8 active sync /dev/sdk1
9 8 177 9 active sync /dev/sdl1
Anyone got any ideas?
Nathan
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