Can someone clarify the meaning of the various memory usage stats in Linux ?
In both top and the graphs provided by Slox, there are categories of
free, buffered, shared, cached - I'm not clear what is buffered.
OK, as I understand it :
free is simply not being used - and normally there shouldn't be much
of it as cached should increase to use most of the spare memory
available.
shared is memory that is used to hold stuff that is shared between
different processes - particularly the in-memory copy of a binary
that is being run multiple times.
cached is used to hold in-memory copies of stuff that is on disk - so
improving performance when/if it is accessed again.
But what is buffered ?
Also, according to the graphs made with rrd, we are running at about
160M free, 150M buffered, 780M shared, and 930M cached - 2G total.
top reports about 110M free, 0 shared (I assume that is what shrd
means), and 150M buffered. The differences in the numbers can be
explained by timing (they were taken at different times), but the
difference between 780M and 0M shared - is that just a different way
of reporting the usage ?
Simon
--
Simon Hobson MA MIEE, Technology Specialist
Colony Gift Corporation Limited
Lindal in Furness, Ulverston, Cumbria, LA12 0LD
Tel 01229 461100, Fax 01229 461101
Registered in England No. 1499611
Regd. Office : 100 New Bridge Street, London, EC4V 6JA.
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