Logical Device Expansion (Lde) - Fujitsu Eternus DX80 S2 User Manual

Chapter 3 Setup
3.6 Optimizing Volume Configurations
• TPPs or FTRPs under any of the following conditions cannot be selected as the RAID
Migration destination.
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*1:
• RAID levels that are supported by the ETERNUS DX Disk storage system can be set for the
source and destination RAID groups.
• The final volume number (LUN) will be the same as the initial volume number, and from the
point of view of the server, pre-migration, migrating and post-migration volumes are accessed
indistinguishably.
• If the power is turned off or an electrical power outage occurs during RAID Migration, the
process will simply continue when the power is restored.
• When expanding the capacity of TPVs, use the Thin Provisioning Volume expansion function
before RAID Migration starts or after RAID Migration is complete.
• When expanding the capacity of FTVs, use the "Expand Flexible Tier Volume" function of
ETERNUS CLI before RAID Migration starts or after RAID Migration is complete.
• When RAID Migration 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.
3.6.2

Logical Device Expansion (LDE)

Logical Device Expansion (LDE) allows the capacity of an existing RAID group to be dynamically
expanded by the addition of extra drives. By expanding the capacity of existing RAID group, a
new volume can be added without having to add new RAID groups.
This section describes the restrictions and notes on using LDE.
For details on the LDE procedure, refer to "ETERNUS Web GUI User's Guide" or "ETERNUS
CLI User's Guide".
• A RAID group can be specified as a target for LDE.
• Multiple LDEs cannot be performed simultaneously.
• LDE can be performed if the new RAID group capacity is the same or larger than the old
capacity.
• When adding drives, use drives that have the same capacity and speed as the drives that
configure the target RAID group. If drives of different capacities exist in a RAID group, the
smallest capacity becomes the standard for the RAID group after expansion, and all other
drives are regarded as having the same capacity as the smallest drive. In this case, the
remaining drive space is not used. In addition, if drives of different speeds exist in a RAID
group, the access performance of the RAID group is reduced by the slower drives.
• If the drives that configure the target RAID group are SSDs, SSDs must be used when adding
drives.
ETERNUS DX80 S2/DX90 S2 Disk storage system User's Guide -Operation-
When the capacity of TPP or FTRP is less than the capacity of the migration source
volume (*1)
When the capacity of the migration source volume is equal to or larger than the maximum
capacity of TPP or FTRP for each model
When the migration source is a TPV or a FTV, the migration source volume capacity indicates the
used capacity (physical capacity allocated from TPP or FTRP).
Copyright 2012 FUJITSU LIMITED
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