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Qsan Document – User Manual
Figure 6: Capacity policy settings
Automatic space reclamation to recycle unused space and increase utilization rate.
Automatic space reclamation will be automatically activated in RAID group initialization
process or it can be set manually through capacity policy. You can set as many as 16 policies.
When space usage ratio grows over the threshold set in the policy, space reclamation will be
enabled automatically at the background with the lowest priority or when the I/O is low. The
resource impact is reduced to minimum.
Figure 7: Space reclamation
Thin Provisioning Case
We suggest that you apply QThin to non-critical production applications first. Thin provisioning
works well when the data written is thin-friendly, which means that the data written is not
completely spread across the whole volume. Applications that spread metadata across the entire
volume will obviate the advantages of thin provisioning. Some applications that expect the data to
be contiguous at block level are not good candidates for thin provisioning as well.
