[Gluster-devel] Re : HA +unify design with multiply server with multiple client

[Raghavendra G]

Hi Mohan,
please find the inlined comments.

2009/1/23 mohan L <l.mohanphy at gmail.com>

> Dear All ,
>
> I am trying to design high available and cluster set up for my benchmarking
> .Today I read  some design information available in GlusterFS home page .
>
>
>
> http://www.gluster.org/docs/index.php/Simple_High_Availability_Storage_with_GlusterFS_2.0#Larger_storage_using_Unify_.2B_AFR
>
>   It is configured using 6 server single client .server 1 and server 2 has
> two  directory /export and /export-ns .
>
> volume brick1
>  type protocol/client
>  option transport-type tcp
>  option remote-host 192.168.1.1      # IP address of the remote brick
>
>  option remote-subvolume brick        # name of the remote volume
> end-volume
>
> From this I understand that
> It will mount the server1(192.168.1.1) exported directory  to client machine mount point
>
> volume brick2
>
>  type protocol/client
>  option transport-type tcp
>  option remote-host 192.168.1.2
>  option remote-subvolume brick
> end-volume
>
> It will mount the server2 (192.168.1.2) exported directory  to client machine mount point
>
>
>
>
> volume brick3
>  type protocol/client
>  option transport-type tcp
>  option remote-host 192.168.1.3
>  option remote-subvolume brick
> end-volume
>
> It will mount the server3 (192.168.1.3) exported directory  to client machine mount point
>
> volume brick4
>  type protocol/client
>  option transport-type tcp
>  option remote-host 192.168.1.4
>  option remote-subvolume brick
> end-volume
>
> It will mount the server4 (192.168.1.4) exported directory  to client machine mount point
>
> volume brick5
>  type protocol/client
>  option transport-type tcp
>  option remote-host 192.168.1.5
>  option remote-subvolume brick
> end-volume
>
> It will mount the server5 (192.168.1.5) exported directory  to client machine mount point
>
> volume brick6
>  type protocol/client
>  option transport-type tcp
>  option remote-host 192.168.1.6
>  option remote-subvolume brick
> end-volume
>
> It will mount the server6 (192.168.1.6) exported directory  to client machine mount point
>
> volume brick-ns1
>  type protocol/client
>  option transport-type tcp
>  option remote-host 192.168.1.1
>  option remote-subvolume brick-ns  *# Note the different remote volume name.*
> end-volume
>
> It will mount the server1(192.168.1.1) exported directory (/home/export-ns/
>
> ) to client machine mount point
>
>
> volume brick-ns2
>  type protocol/client
>  option transport-type tcp
>  option remote-host 192.168.1.2
>  option remote-subvolume brick-ns  *# Note the different remote volume name.*
>
> end-volume
>
> It will mount the server2(192.168.1.2) exported directory (/home/export-ns/
> ) to client machine mount point
>
>
>
> volume afr1
>  type cluster/afr
>  subvolumes brick1 brick4
> end-volume
>
> Here  brick1 replicates all files to brick4 ,Is it correct?
>
>
yes.


>
>
> volume afr2
>  type cluster/afr
>  subvolumes brick2 brick5
> end-volume
>
> volume afr3
>  type cluster/afr
>  subvolumes brick3 brick6
> end-volume
>
> volume afr-ns
>  type cluster/afr
>  subvolumes brick-ns1 brick-ns2
> end-volume
>
> Here the namespace information are replicating .Is it correc?
>
> volume unify
>  type cluster/unify
>  option namespace afr-ns
>
>  option scheduler rr
>  subvolumes afr1 afr2 afr3
> end-volume
>
> what actuly unify does here?


unify is used to aggregate the contents of afr1, afr2 and afr3. Say
following is the list of files on afr1, afr2 and afr3,

afr1: file-1
afr2: file-2
afr3: file-3

then using unify to aggregate all the three afr subvolumes results in a
filesystem containing all the three files.

unify (of afr1, afr2, afr3): file-1, file-2, file-3.


> what is the meaning of namespace in GlusterFS?


namespace is just a cache, which holds the directory tree of unify. Please
note that the files contained in this directory tree are of zero byte sized.



> what about storage scalibality in this design? both server and client. can
> you please give one example ?


only bottleneck in scalability is the namespace node. It should be able to
hold the entire directory structure of unify (with zero byte sized files).
Other than that, a new node can be added just by changing the configuration
file and remounting glusterfs.


>
> how can do HA +unify design with multiply server with multiple client?for
> example 8 server two client .


If replication is not needed, each of the client can have unify of all the
volumes exported by servers.

volume unify
  type cluster/unify
  subvolumes ha1, ha2..... ha8.
end-volume

and ha1, ha2.. ha8  provide High availability using multiple links to the
same server.

say,
volume ha1
  type cluster/ha
  subvolumes client-1a, client-1b
end-volume

where client-1a and client-1b are two different links to server1.

regards,


>
>
>  any one please help me to understand those and correct me .
>
> Thanks for your time
>  L. Mohan
>
>
>
>
>
>
>
>
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>
>


-- 
Raghavendra G
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