QNAP TVS-472XT 4-Bay NAS Enclosure - Manual (Page 116)

Configuration SSD Usage HDD Usage
Qtier Storage Pool Qtier Storage Pool (combined with
HDDs)
Qtier Storage Pool (combined with
SSDs)
SSD Cache SSD cache HDD-only storage pool
All-SSD Storage Pool SSD-only storage pool HDD-only storage pool
Qtier, SSD Cache, and All-SSD Storage Pool Comparison
Qtier Storage Pool SSD Cache All-SSD Storage Pool
Total file storage space High (SSDs + HDDs) Moderate (HDDs only) Low (SSDs only)
Maximum SSD capacity No limit Up to 4 TB depending on
installed memory
No limit
SSD expansion Expand as needed Limited by available
memory
Expand as needed
Applicable storage Thick volumes, thin
volumes and block-based
LUNs in the pool
All volumes and LUNs on
the NAS
Volumes and LUNs
created on the SSDs
Data migration Scheduled or when NAS
load is low
Automatic No migration required
Data migration method QTS writes incoming data
to the SSD tier and
moves data to different
tiers based on access
frequency.
• Write cache: QTS
writes incoming data
to the SSD cache
and then flushes
the cache to disk
periodically.
• Read cache: QTS
copies data to the
cache as it is
accessed.
No migration required
Recommended use cases • Total SSD capacity is
high
• I/O is predictable
• The storage pool
only occasionally
experiences periods
of intense random
I/O access
• I/O is unpredictable
and frequently
happens in random
bursts
• Home usage, where
the NAS will be used
for a large range of
different applications
Applications require
consistent intensive
random read-write
access
Usage examples File server, web server,
email servers, basic
database services (With
Qtier IO Aware)
Video editing,
virtualization
Business critical database
or other application
Qtier Requirements
NAS Requirements
• The NAS must support Qtier. For a full list of compatible models, see https://www.qnap.com/solution/
qtier-auto-tiering .
QTS 4.4.x User Guide
Storage & Snapshots 115