[Gluster-users] webserver setup with 6 nodes

[Christian Meisinger]

hi there.


i've 6 load-balanced webservers running with apache 2.0.
right now we use unison to upload file changes from the developers to server 1
and then 'sync' those changes to 2, 3 andsoon.

additionally if a file is created on one of the servers (like a temporary download created with php)
we 'sync' that file with scp. for safety there are unisons running every 10mins on some servers
to ensure all files are available on every server.

right now it's not a problem with only 6 servers but i'm pretty sure it will become a big problem
with more servers...


so i started some tests GlusterFS 2.0.0rc2.
right now i think two setups may suit us:

layout 1:
  node1-replicate-node2 \
  node3-replicate-node4 - --> distribute  ( like raid0 over 3 x raid1 )
  node5-replicate-node6 /

or

layout 2:
  node1-replicate-node2-replicate-node3 \
  node4-replicate-node5-replicate-node6 - --> distribute  ( like raid0 over 2 x raid5 :) )

i think layout 1 should be ok, because until now i've never seen 2 servers crash at the same time.


my problem is: what happens if we get additional servers?
i've tested layout 1 with 4 nodes, shutdown GLFS, added node5-replicate-node6 to the distrubite translator and started
again. files were ok but i got alot of GLFS errors in the log files.
can i safely ignore them?
i know the manual says: use distribute for fresh installations else unify.
still i'm curious if it would work with distribute.


btw. for GlusterFS version 2.0 is AFR = replicate?


thanks for any suggestions :)