arcstat and arc_summary report impossible value for L2 cache size

[clhedrick]

System information

Type	Version/Name
Distribution Name	Ubuntu
Distribution Version	22.04
Kernel Version	6.6.44
Architecture	x64
OpenZFS Version	2.2.6

Describe the problem you're observing

arc_summary shows

L2ARC size (adaptive): 44.5 TiB
Compressed: 12.5 % 5.6 TiB
Header size: 0.1 % 33.1 GiB
MFU allocated size: 10.5 % 601.1 GiB
MRU allocated size: 89.4 % 5.0 TiB
Prefetch allocated size: 0.1 % 7.1 GiB
Data (buffer content) allocated size: 100.1 % 5.6 TiB
Metadata (buffer content) allocated size: < 0.1 % 214.9 MiB

We have a little under 6 TB of disk assigned, so the 44 TB size seems impossible.

Looking at the last few months, I see values as high as 85 TB.

The same data appears in arcstat.

Describe how to reproduce the problem

n.a

Include any warning/errors/backtraces from the system logs

[imwhocodes]

I'm not a dev but as far I understand OpenZFS you have a lot of highly compressible data, the actual on-disk-size of L2ARC is around 5.6TB (second line) that when decompressed will inflate to 44TB