Marcus Herou wrote:
Thanks for the answer Kevan. I've read quite a lot about GlusterFS but
haven't got the chance yet to test it. (Board dp if I can buy all that
hardware :)
However the conf was ripped from
http://www.gluster.org/docs/index.php/Unify_over_AFR but stripped down to
three instead of six nodes.
Please show me the error it would be more helpful than a 1000 lines of
reading.
Specifically, you can't have a volume (e.g. brick2 in your config) be a
sub-volume of two different AFRs. The solution is to have each server
export two volumes, such as brick2-1 and brick2-2, that way each volume
can be a member in it's own AFR.
Extending this to three servers and three AFRs, you get:
AFR1 { brick1-2, brick2-1 }
AFR2 { brick2-2, brick3-1 }
AFR3 { brick3-2, brick1-1 }
This makes adding a new server (brick4) a bit more complicated, as if
you want everything to line up pretty like above you would want to
copy/move all brick1-1's data to brick4-1, and use the following AFR
definitions:
AFR1 { brick1-2, brick2-1 }
AFR2 { brick2-2, brick3-1 }
AFR3 { brick3-2, brick4-1 }
AFR4 { brick4-2, brick1-1 }
Thanks for the headsup of find... So adding a server which needs TB of data
would not be something you would like to execute everyday I guess... Can you
prefill it with yesterdays possibly "stale" data and then execute the same
find so only new/updated files get's transferred ? I would like to have it
as warm as possible before putting it online if you know what I mean.
There were some recent threads on this, and problems someone was
encountering with pre-populating data, but that might have been with
deploying the initial data set (where the xattrs holding AFR file
versions weren't set).
I assume you could rsync the active file set from another node of the
AFR to the new server with -X to preserve xattrs and go from there, but
it's been a while since I looked in detail at the xattrs used to keep
AFR state. I'm sure someone else will jump in with more info on this,
as it seems to be an active (or at least frequent) topic on the list.
--
-Kevan Benson
-A-1 Networks
