Re: geo-replication

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hi Marcus,

There are no issues with geo-rep and disperse volumes. It works with disperse volume
being master or slave or both. You can run replicated distributed at master and diperse distributed
at slave or disperse distributed at both master and slave. There was an issue with lookup on / taking
longer time because of eager locks in disperse and that's been fixed. Which version are you running?

Thanks,
Kotresh HR

On Fri, Mar 2, 2018 at 3:05 PM, Marcus Pedersén <marcus.pedersen@xxxxxx> wrote:
Hi again,
I have been testing and reading up on other solutions
and just wanted to check if my ideas are ok.
I have been looking at dispersed volumes and wonder if there are any
problems running replicated-distributed cluster on the master node and
a dispersed-distributed cluster on the slave side of a geo-replication.
Second thought, running disperesed on both sides, is that a problem
(Master: dispersed-distributed, slave: dispersed-distributed)?

Many thanks in advance!

Best regards
Marcus


On Thu, Feb 08, 2018 at 02:57:48PM +0530, Kotresh Hiremath Ravishankar wrote:
> Answers inline
>
> On Thu, Feb 8, 2018 at 1:26 PM, Marcus Pedersén <marcus.pedersen@xxxxxx>
> wrote:
>
> > Thank you, Kotresh
> >
> > I talked to your storage colleagues at Open Source Summit in Prag last
> > year.
> > I described my layout idea for them and they said it was a good solution.
> > Sorry if I mail you in private, but I see this as your internal matters.
> >
> > The reason that I seem stressed is that I have already placed my order
> > on new file servers for this so I need to change that as soon as possible.
> >
> > So, a last double check with you:
> > If I build the master cluster as I thought from the beginning,
> > distributed/replicated (replica 3 arbiter 1) and in total 4 file servers
> > and one arbiter (same arbiter used for both "pairs"),
> > and build the slave cluster the same, distributed/replicated (replica 3
> > arbiter 1)
> > and in total 4 file servers and one arbiter (same arbiter used for both
> > "pairs").
> > Do I get a good technical solution?
> >
>
>      Yes, that works fine.
>
> >
> > I liked your description on how the sync works, that made me understand
> > much
> > better how the system works!
> >
>
> Thank you very much for all your help!
> >
>
>  No problem. We are happy to help you.
>
> >
> > Best regards
> > Marcus
> >
> >
> > On Wed, Feb 07, 2018 at 09:40:32PM +0530, Kotresh Hiremath Ravishankar
> > wrote:
> > > Answers inline
> > >
> > > On Wed, Feb 7, 2018 at 8:44 PM, Marcus Pedersén <marcus.pedersen@xxxxxx>
> > > wrote:
> > >
> > > > Thank you for your help!
> > > > Just to make things clear to me (and get a better understanding of
> > > > gluster):
> > > > So, if I make the slave cluster just distributed and node 1 goes down,
> > > > data (say file.txt) that belongs to node 1 will not be synced.
> > > > When node 1 comes back up does the master not realize that file.txt
> > has not
> > > > been synced and makes sure that it is synced when it has contact with
> > node
> > > > 1 again?
> > > > So file.txt will not exist on node 1 at all?
> > > >
> > >
> > > Geo-replication syncs changes based on changelog journal which records
> > all
> > > the file operations.
> > > It syncs every file in two steps
> > > 1. File creation with same attributes as on master via rpc (CREATE is
> > > recorded in changelog)
> > > 2. Data sync via rsync (DATA is recorded in changelog. Any further
> > appends
> > > will only record DATA)
> > >
> > > The changelog processing will not halt on encountering ENOENT(It thinks
> > > it's a safe error). It's not
> > > straight forward. When I said, file won't be synced, it means the file is
> > > created on node1 and when
> > > you append the data, the data would not sync as it gets ENOENT since the
> > > node1 is down. But if the
> > > 'CREATE' of file is not synced to node1, then it is persistent failure
> > > (ENOTCON) and waits till node1 comes back.
> > >
> > > >
> > > > I did a small test on my testing machines.
> > > > Turned one of the geo machines off and created 10000 files containing
> > one
> > > > short string in the master nodes.
> > > > Nothing became synced with the geo slaves.
> > > > When I turned on the geo machine again all 10000 files were synced to
> > the
> > > > geo slaves.
> > > > Ofcause devided between the two machines.
> > > > Is this the right/expected behavior of geo-replication with a
> > distributed
> > > > cluster?
> > > >
> > >
> > > Yes, it's correct. As I said earlier, CREATE itself would have failed
> > with
> > > ENOTCON. geo-rep waited till slave comes back.
> > > Bring slave node down, and now append data to files which falls under
> > node
> > > which is down, you won't see appended data.
> > > So it's always recommended to use replica/ec/arbiter
> > >
> > > >
> > > > Many thanks in advance!
> > > >
> > > > Regards
> > > > Marcus
> > > >
> > > >
> > > > On Wed, Feb 07, 2018 at 06:39:20PM +0530, Kotresh Hiremath Ravishankar
> > > > wrote:
> > > > > We are happy to help you out. Please find the answers inline.
> > > > >
> > > > > On Tue, Feb 6, 2018 at 4:39 PM, Marcus Pedersén <
> > marcus.pedersen@xxxxxx>
> > > > > wrote:
> > > > >
> > > > > > Hi all,
> > > > > >
> > > > > > I am planning my new gluster system and tested things out in
> > > > > > a bunch of virtual machines.
> > > > > > I need a bit of help to understand how geo-replication behaves.
> > > > > >
> > > > > > I have a master gluster cluster replica 2
> > > > > > (in production I will use an arbiter and replicatied/distributed)
> > > > > > and the geo cluster is distributed with 2 machines.
> > > > > > (in production I will have the geo cluster distributed)
> > > > > >
> > > > >
> > > > > It's recommended to use slave also to be distribute
> > > > replicate/aribiter/ec.
> > > > > Choosing only distribute will cause issues
> > > > > when of the slave node is down and a file is being synced which
> > belongs
> > > > to
> > > > > that node. It would not sync
> > > > > later.
> > > > >
> > > > >
> > > > > > Everything is up and running and creating files from client both
> > > > > > replicates and is distributed in the geo cluster.
> > > > > >
> > > > > > The thing I am wondering about is:
> > > > > > When I run: gluster volume geo-replication status
> > > > > > I see both slave nodes one is active and the other is passive.
> > > > > >
> > > > > > MASTER NODE    MASTER VOL     MASTER BRICK    SLAVE USER    SLAVE
> > > > > >                                 SLAVE NODE      STATUS     CRAWL
> > STATUS
> > > > > >    LAST_SYNCED
> > > > > > ------------------------------------------------------------
> > > > > > ------------------------------------------------------------
> > > > > > ---------------------------------------------------
> > > > > > gluster1       interbullfs    /interbullfs    geouser
> > > > > >  ssh://geouser@gluster-geo1::interbullfs-geo    gluster-geo2
> > Active
> > > > > >  Changelog Crawl    2018-02-06 11:46:08
> > > > > > gluster2       interbullfs    /interbullfs    geouser
> > > > > >  ssh://geouser@gluster-geo1::interbullfs-geo    gluster-geo1
> > > > Passive
> > > > > >   N/A                N/A
> > > > > >
> > > > > >
> > > > > > If I shutdown the active slave the status changes to faulty
> > > > > > and the other one continues to be passive.
> > > > > >
> > > > >
> > > > > > MASTER NODE    MASTER VOL     MASTER BRICK    SLAVE USER    SLAVE
> > > > > >                                 SLAVE NODE      STATUS     CRAWL
> > STATUS
> > > > > > LAST_SYNCED
> > > > > > ------------------------------------------------------------
> > > > > > ------------------------------------------------------------
> > > > > > ----------------------------------------
> > > > > > gluster1       interbullfs    /interbullfs    geouser
> > > > > >  ssh://geouser@gluster-geo1::interbullfs-geo    N/A
> >  Faulty
> > > > > >  N/A             N/A
> > > > > > gluster2       interbullfs    /interbullfs    geouser
> > > > > >  ssh://geouser@gluster-geo1::interbullfs-geo    gluster-geo1
> > > > Passive
> > > > > >   N/A             N/A
> > > > > >
> > > > > >
> > > > > > In my understanding I thought that if the active slave stopped
> > > > > > working the passive slave should become active and should
> > > > > > continue to replicate from master.
> > > > > >
> > > > > > Am I wrong? Is there just one active slave if it is setup as
> > > > > > a distributed system?
> > > > > >
> > > > >
> > > > > The Active/Passive notion is for master node. If gluster1 master
> > node is
> > > > > down  glusterd2 master node will become Active.
> > > > > It's not for slave node.
> > > > >
> > > > >
> > > > >
> > > > > >
> > > > > > What I use:
> > > > > > Centos 7, gluster 3.12
> > > > > > I have followed the geo instructions:
> > > > > > http://docs.gluster.org/en/latest/Administrator%20Guide/Geo%
> > > > 20Replication/
> > > > > >
> > > > > > Many thanks in advance!
> > > > > >
> > > > > > Bets regards
> > > > > > Marcus
> > > > > >
> > > > > > --
> > > > > > **************************************************
> > > > > > * Marcus Pedersén                                *
> > > > > > * System administrator                           *
> > > > > > **************************************************
> > > > > > * Interbull Centre                               *
> > > > > > * ================                               *
> > > > > > * Department of Animal Breeding & Genetics — SLU *
> > > > > > * Box 7023, SE-750 07                            *
> > > > > > * Uppsala, Sweden                                *
> > > > > > **************************************************
> > > > > > * Visiting address:                              *
> > > > > > * Room 55614, Ulls väg 26, Ultuna                *
> > > > > > * Uppsala                                        *
> > > > > > * Sweden                                         *
> > > > > > *                                                *
> > > > > > * Tel: +46-(0)18-67 1962                         *
> > > > > > *                                                *
> > > > > > **************************************************
> > > > > > *     ISO 9001 Bureau Veritas No SE004561-1      *
> > > > > > **************************************************
> > > > > > _______________________________________________
> > > > > > Gluster-users mailing list
> > > > > > Gluster-users@xxxxxxxxxxx
> > > > > > http://lists.gluster.org/mailman/listinfo/gluster-users
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > --
> > > > > Thanks and Regards,
> > > > > Kotresh H R
> > > >
> > > > --
> > > > **************************************************
> > > > * Marcus Pedersén                                *
> > > > * System administrator                           *
> > > > **************************************************
> > > > * Interbull Centre                               *
> > > > * ================                               *
> > > > * Department of Animal Breeding & Genetics — SLU *
> > > > * Box 7023, SE-750 07                            *
> > > > * Uppsala, Sweden                                *
> > > > **************************************************
> > > > * Visiting address:                              *
> > > > * Room 55614, Ulls väg 26, Ultuna                *
> > > > * Uppsala                                        *
> > > > * Sweden                                         *
> > > > *                                                *
> > > > * Tel: +46-(0)18-67 1962                         *
> > > > *                                                *
> > > > **************************************************
> > > > *     ISO 9001 Bureau Veritas No SE004561-1      *
> > > > **************************************************
> > > >
> > >
> > >
> > >
> > > --
> > > Thanks and Regards,
> > > Kotresh H R
> >
> > --
> > **************************************************
> > * Marcus Pedersén                                *
> > * System administrator                           *
> > **************************************************
> > * Interbull Centre                               *
> > * ================                               *
> > * Department of Animal Breeding & Genetics — SLU *
> > * Box 7023, SE-750 07                            *
> > * Uppsala, Sweden                                *
> > **************************************************
> > * Visiting address:                              *
> > * Room 55614, Ulls väg 26, Ultuna                *
> > * Uppsala                                        *
> > * Sweden                                         *
> > *                                                *
> > * Tel: +46-(0)18-67 1962                         *
> > *                                                *
> > **************************************************
> > *     ISO 9001 Bureau Veritas No SE004561-1      *
> > **************************************************
> >
>
>
>
> --
> Thanks and Regards,
> Kotresh H R

--
**************************************************
* Marcus Pedersén                                *
* System administrator                           *
**************************************************
* Interbull Centre                               *
* ================                               *
* Department of Animal Breeding & Genetics — SLU *
* Box 7023, SE-750 07                            *
* Uppsala, Sweden                                *
**************************************************
* Visiting address:                              *
* Room 55614, Ulls väg 26, Ultuna                *
* Uppsala                                        *
* Sweden                                         *
*                                                *
* Tel: +46-(0)18-67 1962                         *
*                                                *
**************************************************
*     ISO 9001 Bureau Veritas No SE004561-1      *
**************************************************



--
Thanks and Regards,
Kotresh H R
_______________________________________________
Gluster-users mailing list
Gluster-users@xxxxxxxxxxx
http://lists.gluster.org/mailman/listinfo/gluster-users

[Index of Archives]     [Gluster Development]     [Linux Filesytems Development]     [Linux ARM Kernel]     [Linux ARM]     [Linux Omap]     [Fedora ARM]     [IETF Annouce]     [Bugtraq]     [Linux OMAP]     [Linux MIPS]     [eCos]     [Asterisk Internet PBX]     [Linux API]

  Powered by Linux