QNAP TVS-472XT 4-Bay NAS Enclosure - Manual (Page 147)

Setting Description
Cache replacement policy Specify how data is removed from the SSD cache.
Choose one of the following options:
• Least recently used (LRU): Better cache
performance but uses more CPU resources. This
is the default option.
• First in first out (FIFO): Lower CPU usage than
LRU but might cause worse cache performance.
11. Click Next.
12. Select which volumes and LUNs can use the SSD cache.
Important
For data safety, volumes and LUNs created on an external storage device cannot use the SSD
cache if the cache type is
Read-write
.
13. Click Next.
14. Click Create.
A confirmation message appears.
15. Select I understand and then click OK.
Expanding the SSD Cache
The SSD cache can be expanded by adding a new SSD RAID group.
Important
Expanding the SSD cache clears all cached data.
1. Go to Storage & Snapshots > Storage > Cache Acceleration .
2. Click Manage and then select Expand.
A confirmation message appears.
3. Click OK.
4. Select one or more SSDs.
Warning
All data on the selected disks will be deleted.
5. Select a RAID type.
Warning
Selecting a RAID type with no disk failure protection (Single, JBOD, RAID 0) when the cache type
is
Write-only
or
Read-write
may result in data loss.
Tip
RAID 10 provides the best write cache performance.
6. Click Expand.
A confirmation message appears.
QTS 4.4.x User Guide
Storage & Snapshots 146