Machine unresponsive with cache_lock: blocked on... message

Matthew Dillon dillon at
Sun Mar 21 01:09:47 PDT 2010

:I turned off postgres on the box, and at that moment all the used swap
:memory and about 500MB from active memory was cleared. Which raises a
:question: why is HAMMER using so much memory, causing applications like
:postgres to use swap (and thus run slow). The box has over 3GB of usable
:RAM, this should be well enough. I suppose HAMMER is caching the
:postgresql ondisk data? Should it cache it? FBSD+UFS2 with the same
:postgres dataset uses way less memory.
:My other box which runs DF with HAMMER has pretty normal memory usage but
:it doesnt run any database software.

    Well, did you 'ps axl' and look at the VSZ of the processes?  That
    tells you essentially how much memory they have allocated.  It kinda
    sounds like the postgres process might have been eating a lot of
    memory unrelated to the kernel's file caching.

    HAMMER isn't really doing anything any different from UFS when it
    comes to file data caching.

					Matthew Dillon 
					<dillon at>

More information about the Bugs mailing list