ReclaiMe Data Recovery Training

RAID Recovery Course - Content Analysis Test

Parity test for a full regular RAID5 gives

0% parity in full disk set and 100% parity in all combinations with one disk excluded
100% parity in full disk set and 0% parity in all combinations with one disk excluded
0% parity in full disk set and 0% parity in all combinations with one disk excluded

Check for what parity tests are done

all combinations with one disk excluded
full disk set
each member disk
all disk pairs

If you see one partial mirror pair (60-80%) in mirror map, it points to

RAID1
RAID5
Ex-hotspare disk
RAID10

What does parity analysis calculate?

percent of parity matches in each disk pair
percent of parity matches in each disk
percent of parity matches in disk set

Check the possible RAID levels if parity analysis gives you 0% parity both for full disk set and exclusion combinations

You should do mirror analysis before parity analysis because

mirror analysis helps calculate parity more accurately
mirrors are always even and therefore parity analysis does not apply to mirrors
parity analysis destroys mirror data

Look at the picture and choose the possible variant

Disks {4,5,6} belong to one RAID; Disk 7 is a hotspare
Disks {4,5,7} belong to one RAID; Disk 6 is a hotspare
Disks {5,6,7} belong to one RAID; Disk 4 is a hotspare

What does content analysis help determine?

block size
disk order
RAID level

Look at the picture on the right and check the possible RAID level(s)

RAID 5 with a missing disk
full RAID5
RAID10
RAID0

Look at the picture on the right and guess the possible RAID level

full RAID5
full RAID 5 with a hotspare
RAID 5 with a missing disk
RAID10

Next lesson - Parity Analysis

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