By default for a maximum of 8 txg a metaslab can remain loaded in memory without having any allocations from it.
This number can be too low for some system which can be a potentially load/unload metaslabs too frequently and therefore we leave it to user's choice by making it tunable through kstat.
By default for a maximum of 8 txg a metaslab can remain loaded in memory without having any allocations from it. This number can be too low for some system which can be a potentially load/unload metaslabs too frequently and therefore we leave it to user's choice by making it tunable through kstat.