On Mar 9, 2010, at 4:39 PM, Scott Carey wrote: > > On Mar 8, 2010, at 11:00 PM, Greg Smith wrote: > > * At least with CentOS 5.3 and thier xfs version (non-Redhat, CentOS extras) sparse random writes could almost hang a file system. They were VERY slow. I have not tested since. > Just to be clear, I mean random writes to a _sparse file_. You can cause this condition with the 'fio' tool, which will by default allocate a file for write as a sparse file, then write to it. If the whole thing is written to first, then random writes are fine. Postgres only writes random when it overwrites a page, otherwise its always an append operation AFAIK. > -- > Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-performance -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
