Specifications

ES/OL
Evaluator Series On-Line™
Storage Systems
Product Analysis
May, 2011
Page 9 of 30
Analysis of Fujitsu ETERNUS DX400 S2
Models DX410 and DX440
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Hot Spare
Hot spare disk drives are global spares that may be used by any RAID group with access to the hot spare.
The hot spares allow rebuilding to start automatically when a disk drive fails, or before failure if a high drive
error rate is detected. After replacing a failed drive, the data is copied to the replaced drive and the original
spare returned to spare status. If using different capacity drives in the system, the hot spare must be equal to
or greater than the largest capacity drive. Hot spares are defined to the system via the ETERNUSmgr
function.
When SAS, nearline SAS, and SSD drives are installed, hot spare disks must be defined for each type.
When invoking hot sparing, a hot spare disk with the same capacity as the failed disk will be used first; if one
does not exist, the largest capacity hot spare disk will be used. There is no limit for the number of hot spares
that can be defined.
Disk Drives
The ETERNUS DX410 S2 and DX440 S2 support multiple drive types, capacities and physical sizes. The disk
drive types correspond to different workloads, IO centric for SSD, mixed performance capacity for enterprise
15k and 10k rpm drives, and capacity centric for the nearline 7.2k rpm drives. Both SFF (2.5”) and LFF (3.5”)
form factor drives are supported on the ETERNUS DX410 S2 and DX440 S2.
All drives utilize a Serial Attached SCSI (SAS) 6 Gbit/s interface with dual ports for high availability.
Evaluator Group Comment: Fujitsu has chosen to support both 3.5” and 2.5” drives, providing
significant choice for customers as the industry transitions to the newer 2.5” drive form factor.
Additionally, the ETERNUS DX410 S2 and ETERNUS DX440 S2 systems support SSD drives in both
small and large form factor. Fujitsu is one of the few vendors offering SSD drives in this price class,
which provides users with more choices when configuring for performance and capacity centric
applications.
MAID - ECO-Mode
Fujitsu utilizes Massive Array of Idle Disks (MAID) technology for infrequently accessed data in order to reduce
power and cooling requirements. This feature is referred to as ‘ETERNUS ECO-Mode’. By allowing RAID
groups that are infrequently accessed to spin down when they are not used, the total power consumption may
be reduced.
The ECO-Mode feature controls the disk drive rotation within a RAID group, affecting all drives that form a
RAID group. This feature is managed through ETERNUSmgr. ECO Mode is disabled when system activity
requires access to the RAID group, including for data protection operations, mirror copying, RAID group rebuild
operations and other system required activity.
ECO Mode utilizes a setting, in conjunction with RAID group activity to determine if a RAID group should be
spun down. If there is no activity, and the setting indicates the group should be spun down, then ECO Mode
takes effect. If either of these two conditions is not met, then the group will remain spinning. ECO Mode
utilizes time frames for a specific RAID group. RAID groups may be enabled for the following time frames: