Hi all,
I have a question about FCM behind V9K releasing capacity-reclaim scsi unmap

Our customer was using FS9100 fcm behind V9K equipment.
Since FCM FS9100's user volume capacity was insufficient, we completed the task of virtualizing FS840 equipment behind V9K and moving FS9100 virtualization volume to FS840 pool to increase FS9100's usable capacity,
but we confirmed that FS9100's usable capacity did not increase.

FS9100 Pool virtualized on V9K had free capacity, but FS9100's own usable capacity was not secured.

After finding on the Internet, it seems that this issue occurs because Reclaim is not performed.

The commands for this are:
SVC: "chsystem -backendunmap on" --> From v8.2
Backend FCM Storage: "chsystem -hostunmap on" --> From 8.2
Backend HDD Storage: "chsystem -hostunmap off"

The current firmware version of the customer's V9K is 7.6.
We are not in a situation where we can update the firmware. Is there a way to solve this reclaim issue?

And the customer is wondering whether when a new write occurs in the FS9100 Pool in V9K, it writes to the currently empty Unmapped space or to the currently remaining Usable space.