[OSM-dev] Dev is going to burn soon

Jon Burgess jburgess777 at googlemail.com
Mon May 14 20:43:06 BST 2007


On Mon, 2007-05-14 at 11:12 +0200, Sebastian Spaeth wrote:
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> Sebastian Spaeth wrote:
> > Tile serving from dev has nearly come to a halt. the munin cpuusage stat
> > shows iowait at 87% and load at 6.
> 
> Let me put forward an alternative theory of why that happens:
> So far we focused on hdc (the tile storage) and waited for hdd to
> provide relieve.
> 
> But looking at the IOStats on munin (remote diagnosis like that is to be
> bound to be a little crytal ball watching):
> 
> IOStat (blocks per second read/write):
> 
> Disk	Read	Write
> hdc	68	0
> hdd	33	396
> hda	499	2.2k
> - ---------------------
> Total	600	2.6k
> 
> Ouch, it seems that actually hda is bearing the lions share of all reads
> (ca 83%) and writes (ca 84%). Ouch. How can that be? Apache log file
> entries being written for everything? Plus a MySQL log file entry
> written for everything? It looks like we have to give hda actually some
> relieve here. How full is hda, really?
> 
> Just shooting in the dark, of course. Hope it helps someone.

The mapnik PostgreSQL DB is hosted on dev currently but I guess it could
be moved to tile without any difficulty. Is there any reason to keep it
on dev?

	Jon






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