Space Reclamation Threshold Question
2000-02-03 12:46:17
> I came across strange behavior of one of our ADSM servers concerning space
> reclamation. I have set reclamation threshold to 65 for a tape storagepool.
> So I hope to be correct when expecting only tapes to be reclaimed with 35%
> or fewer actual data on it.
>
> Now I have a tape being reclaimed that "q vol" tells me has 52% pct util !
> Is that correct?? Do I misunderstand the reclamation threshold??
The newer versions of ADSM can group small files into aggregates to facilitate
efficient tape I/O. All of the space on tape used for an aggregate is counted
as occupied space when calculating percent utilization until and unless all
the files making up the aggregate are expired. Space once occupied by expired
files within aggregates is counted as reclaimable space. Volumes become
candidates for reclamation when the percentage of reclaimable space exceeds
the reclamation threshold. The 'query volume' command with 'f=d' shows the
percentage of reclaimable space. The 'select' command can obtain this
information by using the 'pct_reclaim' column of the 'volumes' table.
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