QNAP QTS 4.5 Series User Manual

Qtier 2.0 IO Aware
Qtier 2.0 IO Aware is a feature available in QTS version 4.3.3 or later. With IO Aware, QTS reserves 25% of
the SSD tier capacity in a Qtier storage pool for faster access performance. If data in the capacity or high
speed tiers experiences a high number of read or write requests, QTS immediately moves it to reserved SSD
space instead of waiting to move it using auto-tiering. This improves random I/O performance, offering
performance similar to having an SSD cache.
Qtier and SSD Cache Comparison
Note
Qtier can be used at the same time as SSD cache.
There are three main configuration options when configuring a NAS with a mixture of HDDs and SSDs.
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
QTS 4.5.x User Guide
Storage & Snapshots 237

QNAP QTS 4.5 Series Specifications

General

Brand	QNAP
Model	QTS 4.5 Series
Category	Storage
Language	English