Exadata Hardware - Oracle Exadata Recipes: A Problem-Solution Approach - page 21

All of the storage entities in the System Area are mirrored via software RAID using Linux software RAID. For
example, the Cell Services operating system, cellsrv, is mounted on /opt/oracle on the storage cell. This device is
comprised of physical partitions /dev/sda8 and /dev/sdb8 :
[root@cm01cel01 oracle]# mdadm -Q -D /dev/md8
/dev/md8:
Version : 0.90
Creation Time : Mon Feb 21 13:06:29 2011
Raid Level : raid1
Array Size : 2096384 (2047.59 MiB 2146.70 MB)
Used Dev Size : 2096384 (2047.59 MiB 2146.70 MB)
Raid Devices : 2
Total Devices : 2
Preferred Minor : 8
Persistence : Superblock is persistent
Update Time : Wed Jul 25 13:33:11 2012
State : clean
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
UUID : 4c4b589f:a2e42e48:8847db6b:832284bd
Events : 0.110
Number Major Minor RaidDevice State
0 8 8 0 active sync /dev/sda8
1 8 24 1 active sync /dev/sdb8
[root@cm01cel01 oracle]#
Since the System Area is built on the first two physical disks and only uses a small portion of the total
physical size of the disk, Oracle leaves a large section of the disk unformatted from the host operating system's
perspective. This resides on /dev/sda3 and /dev/sdb3 and is mapped to an Exadata LUN, available to be used
for an Exadata cell disk.
[root@cm01cel01 oracle]# fdisk -l /dev/sda
Disk /dev/sda: 598.9 GB, 598999040000 bytes
255 heads, 63 sectors/track, 72824 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System
/dev/sda1 * 1 15 120456 fd Linux raid autodetect
/dev/sda2 16 16 8032+ 83 Linux
/dev/sda3 17 69039 554427247+ 83 Linux
/dev/sda4 69040 72824 30403012+ f W95 Ext'd (LBA)
/dev/sda5 69040 70344 10482381 fd Linux raid autodetect
/dev/sda6 70345 71649 10482381 fd Linux raid autodetect
/dev/sda7 71650 71910 2096451 fd Linux raid autodetect
/dev/sda8 71911 72171 2096451 fd Linux raid autodetect
/dev/sda9 72172 72432 2096451 fd Linux raid autodetect