FS9 vdisk mirroring will read the entire 2TB volume and it will detect zeros within it. The precise behaviour then depends on what kind of copy it is asked to create.
If the copy is fully allocated then the logical capacity will be allocated but when the data is passed through to the FlashCore Module it will implement thin provisioning and no physical capacity is used.
If the copy is software thin-provisioned then that feature will drop the zeros.
So in both cases there is no physical capacity used but one allocates logical capacity and one doesn't.
Thanks,
Carlos Fuente
Distinguished Engineer, IBM Storage Virtualize, FlashSystem & SVC Family
phone: +44-7795-917197
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Original Message:
Sent: 8/7/2025 11:33:00 PM
From: MAILVAGANAM VELAYUTHAM
Subject: Migration from A9K to FS9500 – Vdisk Mirror (Thin Policy)
Hi All,
For a migration from A9K to FS9500 using vdiskcopy in mirror mode with a Thin policy:
If we migrate a 2 TB volume that currently has 1.7 TB of written data, will FS9500 only copy the actual data (1.7 TB) and ignore the unused space, or will it copy the entire 2 TB?
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Rgrds
MAILVAGANAM VELAYUTHAM
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