flush temp directory

[Igor Sverkos]

H
i,

I would really wonder if you would see a real difference between using a
tmpfs or not for the webserver's tmp body location. A tmpfs is only faster,
but as long as your storage has enough free IO resources and is fast enough
to actual write the data, you shouldn't notice.
And keep in mind: You only use the tmpfs for the request body. But you
still need to write it to disk. If your disk is limited to 120MB/s and a
normal upload is about 5 MB you are only able to handle ~23 concurrent
uploads. Well, you could buffer millions of request per second in your
super fast RAM (if you have enough RAM :P), but your PHP worker, which will
move the upload from RAM to the persistent storage will become the
bottleneck.

I have a problem with the way it seems you test your setup:
Every system should be able to handle that kind of load. After some runs,
everything should be in some kind of cache. The IOs from the uploaded files
are not enough (disks also have write caches, the OS may buffer writes,
too...). These IOs can be handled by every disk, also, the IOs comes in
sequence, not parallel.

=> Add more load. Run tests parallel/concurrent. Increase file size to fill
up any write caches, which will trigger real writes, which will block the
storage in some ways you will notice.

-- 
Regards,
Igor
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