Question about Ignite persistence disk space used after clearing cache

[Scott Prater]

I have a question about how the off-heap usage is reported when Ignite
persistence is configured.  I have a single node set up.  I stored about
1GB of items in the cache, then cleared the cache (remotely, using the Java
thin client:  ClientCache.clear()).

I then verified that the items were no longer in the cache.

However, when I look at the Ignite log, I do not see that the disk space
was freed:

[2020-09-25T11:17:36,299][INFO ][grid-timeout-worker-#23][IgniteKernal]
Metrics for local node (to disable set 'metricsLogFrequency' to 0)
    ^-- Node [id=db4ed295, uptime=00:34:00.176]
    ^-- H/N/C [hosts=1, nodes=1, CPUs=8]
    ^-- CPU [cur=0.2%, avg=0.3%, GC=0%]
    ^-- PageMemory [pages=250315]
    ^-- Heap [used=180MB, free=94.85%, comm=438MB]
    ^-- Off-heap [used=989MB, free=88.35%, comm=8392MB]
    ^--   sysMemPlc region [used=0MB, free=99.99%, comm=100MB]
    ^--   default_region region [used=989MB, free=87.92%, comm=8192MB]
    ^--   metastoreMemPlc region [used=0MB, free=99.94%, comm=0MB]
    ^--   TxLog region [used=0MB, free=100%, comm=100MB]
    ^-- Ignite persistence [used=998MB]
    ^--   sysMemPlc region [used=0MB]
    ^--   default_region region [used=998MB]
    ^--   metastoreMemPlc region [used=0MB]
    ^--   TxLog region [used=0MB]
    ^-- Outbound messages queue [size=0]
    ^-- Public thread pool [active=0, idle=0, qSize=0]
    ^-- System thread pool [active=0, idle=6, qSize=0]

"Ignite persistence [used=998MB]" seems to indicate that 1GB of data is
still in the cache.  Is this simply a report of the disk space *allocated*,
or is actual disk space in use?  Is there a way to get both measurements?

thanks,

-- Scott