[Gluster-users] gluster volume snap shot - basic questions

[Merlin Morgenstern]

Thank you Rjesh for your help. I have a thinly provisioned LVM now running
and can create snapshots on a real device, surviving boot.

There are 2 other questions rising up now.

1. I have a LV with 20G, data is 7G. How is it possible, that I could make
3 snapshots, each 7G?

/dev/mapper/gluster-thinv1                               20G  7.0G   12G
38% /bricks/brick1

/dev/mapper/gluster-7cb4b2c8f8a64ceaba62bc4ca6cd76b2_0   20G  7.0G   12G
38% /run/gluster/snaps/7cb4b2c8f8a64ceaba62bc4ca6cd76b2/brick1

/dev/mapper/gluster-506cb09085b2428e9daca8ac0857c2c9_0   20G  7.0G   12G
38% /run/gluster/snaps/506cb09085b2428e9daca8ac0857c2c9/brick1

/dev/mapper/gluster-fbee900c1cc7407f9527f98206e6566d_0   20G  7.0G   12G
38% /run/gluster/snaps/fbee900c1cc7407f9527f98206e6566d/brick1

/dev/mapper/gluster-d0c254908dca451d8f566be77437c538_0   20G  7.0G   12G
38% /run/gluster/snaps/d0c254908dca451d8f566be77437c538/brick1


2. The name of the snapshot folder is the UUID, My plan is to do a "tar cf"
on the snapshot and even incremental tars. Therefore I would need the name
of the folder. How could I pass that name to my bash script in order to
make a backup of the last snap?


3. A tar process will take hours on the million files I have. I understand
this is a snapshot, is there a way to backup a "single" snapshot file
instead?

Thank you in advance for sheding some light on this topic

2015-09-02 7:59 GMT+02:00 Rajesh Joseph <rjoseph at redhat.com>:

>
>
> ----- Original Message -----
> > From: "Merlin Morgenstern" <merlin.morgenstern at gmail.com>
> > To: "gluster-users" <gluster-users at gluster.org>
> > Sent: Tuesday, September 1, 2015 3:15:43 PM
> > Subject: [Gluster-users] gluster volume snap shot - basic questions
> >
> > Hi everybody,
> >
> > I am looking into the snap shot tool, following this tutorial:
> > http://blog.gluster.org/2014/10/gluster-volume-snapshot-howto/
> >
> > While having successfully created the LVM, gluster volume and one
> snapshot,
> > there are some questions arrising where I was hoping to find some
> guidence
> > here:
> >
> > 1. From a working setup as in the example I rebooted and everything was
> gone.
> > How can I make this setup persistent, so the gluster share is up and
> running
> > after boot.
> >
>
> What do you mean by "everything was gone"? Are you using loop back device
> as disks?
> If yes then this is expected. Loop back device mapping is gone after
> machine restart.
> You should test with real disk or lvm partition.
>
> > 2. I understand that the snaps are under /var/run/gluster/snaps/ and I
> found
> > them there. Is it save to simply copy them to another server for backup?
> My
> > goal is to create a backup each day and transfer the snaps to an
> FTP-Server
> > in order to be able to recover from a broken machine.
> >
>
> Yes, snap of individual bricks are mounted at /var/run/gluster/snaps/. I
> am assuming
> that you mean copy of data hosted on the snap brick when you say copy the
> snap.
> Are you planning to use some backup software or to run rsync on each brick?
>
> > 3. Do I really need LVM to use this feature? Currently my setup works on
> the
> > native system. As I understand the tuturial I would need to move that to
> a
> > LV, right?
> >
>
> Yes, you need LVM and to be precise thinly provisioned LVM for snapshot to
> work.
>
> > Thank you in advance on any help!
> >
> > _______________________________________________
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> > Gluster-users at gluster.org
> > http://www.gluster.org/mailman/listinfo/gluster-users
>
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