Specifications

ES/OL
Evaluator Series On-Line™
Storage Systems
Product Analysis
May, 2011
Page 12 of 30
Analysis of Fujitsu ETERNUS DX400 S2
Models DX410 and DX440
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Evaluator Group Comments: Thin provisioning has become an increasingly important checklist item
feature. The effectiveness of thin provisioning in general is application dependent, with some uses
such as virtual server and VDI implementations providing some of the best uses.
RAID Migration
Fujitsu refers to dynamic migration of a LUN as the ability to copy data from one RAID group to another. Since
on-line RAID migration copies data from one RAID group to another, the target RAID group must be as large,
or larger than the source group. There are few restrictions to RAID migration, allowing administrators to re-
architect data layout to support changing requirements. This provides the ability to manage changing capacity,
performance or availability requirements for data.
LUN Concatenation
LUN concatenation adds new space for a volume and expands volume capacity that can be used from the
server. This feature obtains the area to be used for capacity expansion from unused areas in an existing RAID
group, or an unused RAID group. LUN concatenation creates a new volume with the obtained area, and
concatenates these volumes to be used as a large capacity volume. LUN concatenation can be used for
volume expansion when creating a new volume or expanding an existing volume. Up to 16 volumes may be
concatenated. Concatenation of multiple free areas in different or the same RAID group is possible.
Concatenation is possible even if the RAID level is different.
Disk Traffic Control (DTC)
DTC is a performance optimization that optimizes the back end disk drive by segmenting sequential and
random accesses into separate extents when they both occur simultaneously. The two I/O streams (sequential
and random) are processed alternately on a time interval basis to provide optimum usage of the disk drive
resource.
Other Features
Fujitsu also supports two modes for specific environments:
• Oracle HARD
• Video Streaming Mode
The Oracle HARD feature provides end-to-end data fidelity. This prevents potential corrupt data from being
written to the disk.
The Video streaming mode allows forced prefetching of data when sequential read or write operations are the
predominant workload. This can improve performance for video applications.