Exadata Hardware - Oracle Exadata Recipes: A Problem-Solution Approach - page 19

Based on the /dev/md* Filesystem names, we know we've got software RAID in play for these devices and
that this RAID was created using mdadm . Let's query our mdadm configuration on /dev/md6 (the output is similar
for /dev/md5, /dev/md8, and /dev/md11):
[root@cm01cel01 ~]# mdadm -Q -D /dev/md6
/dev/md6:
Version : 0.90
Creation Time : Mon Feb 21 13:06:27 2011
Raid Level : raid1
Array Size : 10482304 (10.00 GiB 10.73 GB)
Used Dev Size : 10482304 (10.00 GiB 10.73 GB)
Raid Devices : 2
Total Devices : 2
Preferred Minor : 6
Persistence : Superblock is persistent
Update Time : Sun Mar 25 20:50:28 2012
State : active
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
UUID : 2ea655b5:89c5cafc:b8bacc8c:27078485
Events : 0.49
Number Major Minor RaidDevice State
0 8 6 0 active sync /dev/sda6
1 8 22 1 active sync /dev/sdb6
[root@cm01cel01 ~]#
From this output, we can see that the /dev/sda and /dev/sdb physical devices are software mirrored via mdadm .
If you do an fdisk -l on these devices, you will see the following:
[root@cm01cel01 ~]# 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
/dev/sda10 72433 72521 714861 fd Linux raid autodetect