Drive Enclosures; Drives - Fujitsu ETERNUS AF250 Design Manual

3. Hardware Configurations
Optional Product Installation Conditions
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iSCSI
iSCSI is a communication protocol that transfers SCSI commands by encapsulating them in IP packets over Ether-
net.
Since iSCSI can be installed at a lower cost and the network configuration is easier to change than FC, iSCSI is
commonly used by divisions of large companies and by small and medium-sized companies where scalability
and cost-effectiveness are valued over performance.
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Number of Installable Host Interfaces
Two host interfaces can be installed in the controller. Each storage system can be installed with four host inter-
faces.
Different types of host interfaces can exist together in the same ETERNUS AF.

Drive Enclosures

This section explains the installation conditions for drive enclosures.
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Types of Drive Enclosures
Twenty-four 2.5" drives can be installed in a drive enclosure.
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Number of Installable Drive Enclosures
One drive enclosure can be installed.

Drives

This section explains the installation conditions for drives.
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Drive Type
The ETERNUS AF supports SAS SSDs with high-speed (12Gbit/s) interfaces.
SSDs are reliable drives with high performance. SSDs are used to store high performance databases and other
frequently accessed data.
Flash memory as a storage media provides better random access performance. Containing no motors or other
moving parts, they are highly resistant to impact.
The ETERNUS AF supports SSDs that have a high level wear leveling function. Note that if the expected total
write capacity is exceeded, the frequency of errors gradually increases, which may lead to a reduction in the
write performance. The ETERNUS AF has a function that shows the remaining capacity as a percentage (health)
in proportion to the expected total write capacity.
The number of rewrites may exceed the limit within the product warranty period if SSDs are used in a RAID1
configuration that has a high I/O access load. Using a RAID1+0, RAID5, RAID5+0, or RAID6 configuration is rec-
ommended.
The ETERNUS AF supports Value SSDs. They are available at a lower cost per capacity than conventional SSDs by
optimizing the guaranteed write endurance and the reserved space.
Note that the product's actual capacity of a Value SSD differs from the capacity that is displayed in ETERNUS Web
GUI and ETERNUS CLI. For example, 2.00TB is displayed for a 1.92TB Value SSD.
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