[Tilecache] DiskCache through multiple disks

Marco Nijdam marco at west.nl
Mon Jan 16 09:55:20 EST 2012


As quoted from Pedro Miguel  Mendes:
> Can anyone give me a scenario where one could set up multiple disks to
> store
> the tiles in a distributed way? All the disks are in machines in the same
> infrastructure.

How about using a RAID controller with striping across multiple disks.
That could share the write among disks?

Or implement a MultipleDiskCache.py to extend or replace the existing
DiskCache in tilecache with storing the tiles om multiple disks.
E.g. with two disks, store even-numbered tiles on one, and odd-numbered ones
on another.
Adding or removing disks will then be a challenge, since all tiles will be
at the wrong disk.
To avoid that, maybe you could work with e.g. 10 virtual locations for
tiles, and assign one or more to each disk you have. When you want to add a
disk, you only have to re-assign one or more virtual locations from one disk
to the other, and move all files in that virtual location to the other
disk.
Your MultipleDiskCache.py implementation could save the files to the
virtual locations, by using (tile-id mod 10) as the index to them.

Kind regards,
--
-- Marco Nijdam
--





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