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Re: [SLUG] Image rotation for some images taking hours too long.


>>>>> "Michael" == Michael Lake <mikel@xxxxxxxxxxxxxxxxx> writes:


Michael> Questions: What is 'uninterruptable sleep' ? Anyhow pointers
Michael> on how I can speed things up.  Why oh why might a few dozen
Michael> images / 200 take so long when others take 30 seconds?

Uninterruptible sleep is generally waiting for disk I/O -- either swap
or input.

Possibilities are:
	-- a few bad sectors on the disc causing timeouts and retries
	   (check dmesg output)
	-- you've gone over a boundary that means mogrify is using
	   enough memory to need to swap (although I can see no sign
	   of swap usage in your `top' snapshot)
	-- Beginning to run out of disk space meaning that the
	   filesystem has to do a lot of work to allocate space for
	   temporary files or output files.
	-- Disc fragmentation for those files, meaning lots of seek
	   activity to read them.

Try copying the problematic files to a different filesystem and running
your rotate again.

--
Dr Peter Chubb  http://www.gelato.unsw.edu.au  peterc AT gelato.unsw.edu.au
http://www.ertos.nicta.com.au           ERTOS within National ICT Australia