Extreme Cache Pool
The Extreme Cache Pool function uses SSDs in enclosures as the secondary cache to improve the read access per-
formance from the server. Self Encrypting SSDs can be used in addition to SSDs.
Frequently accessed areas are written asynchronously to specified SSDs for Extreme Cache Pools. When a read
request is issued from the server, data is read from the faster SSD to speed up the response.
Either the Extreme Cache function or the Extreme Cache Pool function can be used. Using the faster Extreme
Cache function is recommended.
Figure 29 Extreme Cache Pool
ETERNUS DX
Extreme Cache Pool (SSDs)
Read request
Cache memory
Controller
Disks
When there is a read
request, the response
for the request will be
faster by reading data
from the SSDs instead
of reading data from
the disks.
Frequently accessed
areas are written to
the Extreme Cache
Pool (SSDs)
Specify one to four SSDs to use as an Extreme Cache Pool for each controller.
400GB SSDs (MLC SSDs) can be used for the ETERNUS DX500 S4/DX600 S4. Value SSDs cannot be used.
SSDs with a capacity of 400GB, 800GB, and 1.6TB can be used for the ETERNUS DX500 S3/DX600 S3.
A RAID group (RAID0) that is dedicated to the Extreme Cache Pool is configured with the specified SSDs, and
volumes for the Extreme Cache Pool are crated in the RAID group.
The maximum capacity that can be used as an Extreme Cache Pool is 1,600GB for each controller. If the total
capacity of the selected SSDs exceeds 1,600GB, remaining area cannot be used. If SSDs with different capacities
are selected, the most capacity the RAID group will be created with is equal to the capacity of the smallest SSD.
The Extreme Cache Pool function can be enabled or disabled for each volume. Note that the Extreme Cache Pool
function cannot be enabled for Deduplication/Compression Volumes, or volumes that are configured with SSDs.
One volume for the Extreme Cache Pool is created for each controller. Different capacities can be set for each
controller.
To expand the Extreme Cache Pool capacity, delete the SSD configuration that is used in the Extreme Cache
Pool. After that, select the SSD with the larger capacity or increase the number of member drives in the SSD
configuration, and redefine the SSDs used for the Extreme Cache Pool.
•
SSDs that are already in use cannot be specified for Extreme Cache Pools.
•
The Extreme Cache function may improve random I/O.
2. Basic Functions
Operations Optimization (Virtualization/Automated Storage Tiering)
56
FUJITSU Storage ETERNUS DX500 S4/DX600 S4, ETERNUS DX500 S3/DX600 S3 Hybrid Storage Systems Design Guide (Basic)
Copyright 2019 FUJITSU LIMITED
P3AM-7722-25ENZ0
Summary of Contents for ETERNUS DX500 S3/DX600 S3
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