[Gluster-users] Interesting experiment

[Hiren Joshi]

Hi,
 
Ok, the basic setup is 6 bricks per server, 2 servers. Mirror the six
bricks and DHT them.
 
I'm running three tests, dd 1G of zeros to the gluster mount, dd 1000
100k files and dd 1000 1M files.
 
With 3M write-behind I get:
0m35.460s for 1G file
0m52.427s for 100k files
1m37.209s for 1M files

Then I added a 400M external journal to all the bricks, the twist being
the journals were made on a ram drive....

Running the same tests:
0m33.614s for 1G file
0m52.851s for 100k files
1m31.693s for 1M files


So why is it that adding an external journal (in the ram!) seems to make
no difference at all?