Wide Striping - Fujitsu ETERNUS DX80 S2 User Manual

Chapter 3 Setup
3.7 Optimizing Volume Configurations
• Because the server-side LUNs are not changed by volume concatenation, an OS reboot is not required.
However, this function only expands the volumes in the ETERNUS DX Disk storage system. Server-side
recognition and capacity expansion is OS dependent.
• The logical unit number of each concatenated volume does not change and remains accessible from the
server before, during, and after the concatenation.
• If the power is turned off or an electrical power outage occurs during LUN Concatenation, the
concatenation will simply continue the next time the power is turned on.
• It is recommended that the data on the volumes that are to be concatenated be backed up first.
• When LUN Concatenation is used to increase the volume (LUN) capacities, note that the increased size of
the expanded volumes may not always be dynamically re-recognized by the server, depending on the
server-side OS (type and version) being used. Refer to the applicable OS and file system documentation
before dynamically expanding the volume capacity.
This is not necessary when building a new system after the volume capacity has been expanded.
• A concatenated volume can be used as an OPC, EC, or QuickOPC copy source or copy destination. It can also
be used as a SnapOPC/SnapOPC+ copy source.
• When a volume that is using ETERNUS SF AdvancedCopy Manager to run backups is expanded via LUN
Concatenation, the volume will need to be registered with ETERNUS SF AdvancedCopy Manager again.
3.7.4

Wide Striping

Wide Striping is a function that improves performance by concatenating multiple RAID groups with striping
and using many drives at the same time. This function is especially effective for systems that require write
access performance.
By increasing the number of drives that configure a LUN, process performance is improved by the distribution
of I/O access from the server to multiple drives.
This section describes the points to note when using the Wide Striping function.
For details on Wide Striping settings, refer to "ETERNUS Web GUI User's Guide" or "ETERNUS CLI User's Guide".
• The maximum volume capacity for a Wide Striping Volume (WSV) is 128TB.
• From 2 to 64 RAID groups can be concatenated.
• Wide Striping cannot be used for RAID groups in the following conditions:
- RAID groups that belong to TPPs or FTRPs
- RAID groups that are registered as REC disk buffers
• The number of RAID groups that are to be concatenated is defined when creating a WSV. The number of
concatenated RAID groups cannot be changed after creation. To change the number of RAID groups in a
WSV, use the RAID Migration function and specify a WSV with a different number of RAID groups as the
RAID Migration destination.
• The LUN Concatenation function cannot be used to expand the WSV capacity. To expand the WSV capacity,
use the RAID Migration function and specify a larger capacity for the RAID Migration destination volume.
• The Logical Device Expansion function cannot be used for RAID groups that configure a WSV.
• Different drive types (SAS, Nearline SAS, SSD, and SED) in RAID groups that configure a WSV cannot be
used.
• Free areas in RAID groups that are concatenated by the Wide Striping function can be used to create other
type volumes (Standard/Open, SDV, SDPV, or WSV).
• WSVs can be created by RAID groups when the stripe size is specified during WSV creation. Note that WSVs
cannot be configured by concatenating RAID groups with different stripe sizes.
ETERNUS DX80 S2/DX90 S2 Disk storage system User's Guide -Operation-
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