On 03/20/2013 01:25 PM, Kevin Grittner wrote:
I saw something once which *might* be related. I don't recall the OS of FS involved, but in an attempt to reduce the fragmentation of files which started small and eventually grew large, a large allocation of contiguous space was made on file creation, and that space was not release as long as any page for the file remained in the OS cache.
That was an optimization decision made for XFS in recent kernels, and the chunks it grabs are very, very large. We had to reduce the default allocation size to 1MB to disable the elastic allocation system. In the end, we regained about 50GB of "phantom" space after a re-mount, and it's stayed that way since.
But that's what du --apparent-size is for. :) -- Shaun Thomas OptionsHouse | 141 W. Jackson Blvd. | Suite 500 | Chicago IL, 60604 312-676-8870 sthomas@xxxxxxxxxxxxxxxx ______________________________________________ See http://www.peak6.com/email_disclaimer/ for terms and conditions related to this email -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
