[Gluster-users] novice kind of question.. replication(raid)

[Jenn Fountain]

Jumping on this thread with a relevant  (I think question) - I am new to gluster as well.

Where do you typically work with the files - local or gluster mount?  IE:  /repl/export - local /mnt/glusterfs - gluster mount

Would you work with the files on /repl/export and then copy them (automate this via a script or can gluster automate this) to the /mnt/glusterfs so they replicate or work with them on the /mnt/glusterfs and have them replicate?   Sorry for the novice question but I am a novice. 

-Jenn





On Apr 16, 2010, at 10:01 AM, RW wrote:

> 
>> many thanks Robert for your quick reply,
>> I still probably am missing/misunderstanding the big picture here, what
>> about this:
>> 
>>                            box a  < -- >  box b
>>                            /dir_1             /dir_1
>>                              ^                     ^
>>        serivces locally                     services locally
>>   read/write to dir_1                     read/write to /dir_1
> 
> This is basically the setup I described with my config files.
> /dir_1 (or /some_folder in you former mail) is the client mount.
> Everything you copy in there will be replicated to box a and
> box b. It doesn't matter if you do the copy in box a or b.
> But you need a different location for glusterfsd (the GlusterFS
> daemon) to store the files locally. This could be /opt/glusterfsbackend
> for example. You need this on both hosts and you need the mounts
> (client) on both hosts.
> 
>> - can all these local services/processes, whatever these might be,
>> not know about mountig and all this stuff?
> 
> You need to copy glusterfsd.vol on both hosts e.g. /etc/glusterfs/
> Then you start glusterfsd (on Gentoo this is "/etc/init.d/glusterfsd
> start"). Now you should see a glusterfsd process on both hosts.
> You also copy glusterfs.vol to both hosts. As you can see in my
> /etc/fstab I supply the glusterfs.vol file as the filesystem
> and glusterfs as type. You now mount GlusterFS as you would do
> with every other filesystem. If you now copy a file to /some_folder
> on "box a" it will automatically be replicated to "box b" and after
> that it will be immediately be available at "box b". The replication
> is done by the client (the mountpoint in your case if this
> helps to better understand). The servers basically only provide the
> backend services to store the data somewhere on a brick (host).
> In my example above this was /opt/glusterfsbackend.
> 
>> - and server between themselves make sure(resolve conflicts, etc.)
>> that content of dir_1 on both boxes is the same?
> 
> Most of the time ;-) There're situations where conflicts can
> occur but in this basic setup they're seldom. You have to monitor
> the log files. But GlusterFS provides self healing which means
> that if a backend (host) goes down the files generated on the
> good host - while the bad host is down - will be copied to the failed
> host if it is up again. But this will not happen immediately.
> This is the "magic part" of GlusterFS ;-)
> 
>> - so whatever happens(locally) on box_a is replicated(through "servers")
>> on box_b and vice versa,
>> possible with GlusterFS or I need to be looking for something else?
> 
> As long as you copy the files into the glusterfs mount (in your
> case /some_folder) the files will be copied to "box b" if you
> copy it on "box a" and vice versa.
> 
>> and your configs, do both files glusterfsd and glusterfs go to both
>> box_a & box_b?
> 
> Yes.
> 
>> does mount need to be executed on both boxes as well?
> 
> Yes.
> 
> - Robert
> 
> 
>> thanks again Robert
>> 
>> 
>> 
>> On 16/04/10 13:42, RW wrote:
>>> This is basically the config I'm using for replicate
>>> a directory between two hosts (RAID 1 if you like ;-) )
>>> You need server and client even both are on the same
>>> host:
>>> 
>>> ##########################
>>> # glusterfsd.vol (server):
>>> ##########################
>>> volume posix
>>>  type storage/posix
>>>  option directory /some_folder
>>> end-volume
>>> 
>>> volume locks
>>>  type features/locks
>>>  subvolumes posix
>>> end-volume
>>> 
>>> volume server
>>>  type protocol/server
>>>  option transport-type tcp
>>>  option transport.socket.bind-address .......
>>>  option transport.socket.listen-port 6996
>>>  option auth.addr.locks.allow *
>>>  subvolumes locks
>>> end-volume
>>> 
>>> #########################
>>> # glusterfs.vol (client):
>>> #########################
>>> volume remote1
>>>  type protocol/client
>>>  option transport-type tcp
>>>  option remote-host <ip_or_name_of_box_a>
>>>  option remote-port 6996
>>>  option remote-subvolume locks
>>> end-volume
>>> 
>>> volume remote2
>>>  type protocol/client
>>>  option transport-type tcp
>>>  option remote-host <ip_or_name_of_box_b>
>>>  option remote-port 6996
>>>  option remote-subvolume locks
>>> end-volume
>>> 
>>> volume replicate
>>>  type cluster/replicate
>>>  # optionally but useful if most is reading
>>>  # !!!different values for box a and box b!!!
>>>  # option read-subvolume remote1
>>>  # option read-subvolume remote2
>>>  subvolumes remote1 remote2
>>> end-volume
>>> 
>>> #####################
>>> # /etc/fstab
>>> #####################
>>> /etc/glusterfs/glusterfs.vol /some_folder  glusterfs  noatime  0  0
>>> 
>>> "noatime" is optional of course. Depends on your needs.
>>> 
>>> - Robert
>>> 
>>> 
>>> On 04/16/10 14:18, pawel eljasz wrote:
>>> 
>>>> dear all, I just subscribed and started reading docs,
>>>> but still not sure if I got the hung of it all
>>>> is GlusterFS for something simple like:
>>>> 
>>>> a box <->        b box
>>>> /some_folder                      /some_folder
>>>> 
>>>> so /some_folder on both boxes would contain same data
>>>> 
>>>> if yes, then does setting only the servers suffice? or client side is
>>>> needed too?
>>>> can someone share a simplistic config that would work for above simple
>>>> design?
>>>> 
>>>> cheers
>>>> 
>>>> 
>>>> 
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