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The item, Mark as Journal Disk, allows the user to set the selected NVMe device as a journal
disk. Use the arrow keys to select Mark as Journal Disk and press <Enter>. The following
screen will appear. Options are Yes and No.
Note: RAID Write Hole (RWH) is a condition associated with a power/drive-failure/
crash while writing RAID5 strips. The use of journal disk that contains partial parity
logging (PPL) can reduce the potential data loss. Refer to the following illustration for
the use of journal disk.
Journal
Disk
(PPL)
Store PPL to the journal disk
Appendix B: Standardized Warning Statements
RAID SW for Read-modify-write Case
(read) old data
XOR operation
(write) new data
Disk1
Disk2
(Data)
(Data)
Partial parity logging (PPL) = old data XOR old parity
New parity = new data XOR PPL
133
(read) old parity
XOR operation
(write) new parity
Disk3
Disk4
(Data)
(Parity)
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