Kind-of. That just tells the client what other nodes it can use to retrieve that volume configuration. It's only used during that initial fetch.

On 8/31/22 8:26 AM, Péter Károly JUHÁSZ wrote:
You can also add the mount option: backupvolfile-server to let the client know the other nodes.

Matthew J Black <dulu...@gmail.com> 于 2022年8月31日周三 17:21写道:

    Ah, it all now falls into place: I was unaware that the client
    receives that file upon initial contact with the cluster, and thus
    has that information at hand independently of the cluster nodes.

    Thank you for taking the time to educate a poor newbie - it is
    very much appreciated.

    Cheers

    Dulux-Oz

    On 01/09/2022 01:16, Joe Julian wrote:

    You know when you do a `gluster volume info` and you get the
    whole volume definition, the client graph is built from the same
    info. In fact, if you look in /var/lib/glusterd/vols/$volume_name
    you'll find some ".vol" files. `$volume_name.tcp-fuse.vol` is the
    configuration that the clients receive from whichever server they
    initially connect to. You'll notice that file has multiple
    "type/client" sections, each establishing a tcp connection to a
    server.

    Sidenote: You can also see in that file, how the microkernels are
    used to build all the logic that forms the volume, which is kinda
    cool. Back when I first started using gluster, there was no
    glusterd and you have to build those .vol files by hand.

    On 8/31/22 8:04 AM, Matthew J Black wrote:

    Hi Joe,

    Thanks for getting back to me about this, it was helpful, and I
    really appreciate it.

    I am, however, still (slightly) confused - *how* does the client
    "know" the addresses of the other servers in the cluster (for
    read or write purposes), when all the client has is the line in
    the fstab file: "gfs1:gv1  /data/gv1  glusterfs defaults  0 2"?
    I'm missing something, somewhere, in all of this, and I can't
    work out what that "something" is.  :-)

    Your help truely is appreciated

    Cheers

    Dulux-Oz

    On 01/09/2022 00:55, Joe Julian wrote:

    With a replica volume the client connects and writes to all the
    replicas directly. For reads, when a filename is looked up the
    client checks with all the replicas and, if the file is
    healthy, opens a read connection to the first replica to
    respond (by default).

    If a server is shut down, the client receives the tcp messages
    that close the connection. For read operations, it chooses the
    next server. Writes will just continue to the remaining
    replicas (metadata is stored in extended attributes to inform
    future lookups and the self-healer of file health).

    If a server crashes (no tcp finalization) the volume will pause
    for ping-timeout seconds (42 by default). Then continue as
    above. BTW, that 42 second timeout shouldn't be a big deal. The
    MTBF should be sufficiently far apart that this should still
    easily get you five or six nines.

    On 8/30/22 11:55 PM, duluxoz wrote:

    Hi Guys & Gals,

    A Gluster newbie question for sure, but something I just don't
    "get" (or I've missed in the doco, mailing lists, etc):

    What happens to a Gluster Client when a Gluster Cluster Node
    goes off-line / fails-over?

    How does the Client "know" to use (connect to) another Gluster
    Node in the Gluster Cluster?

    Let me elaborate.

    I've got four hosts: gfs1, gfs2, gfs3, and client4 sitting on
    192.168.1.1/24 <http://192.168.1.1/24>, .2, .3, and .4
    respectively.

    DNS is set up and working correctly.

    gfs1, gs2, and gfs3 form a "Gluster Cluster" with a Gluster
    Volume (gv1) replicated across all three nodes. This is all
    working correctly (ie a file (file1) created/modified on
    gfs1:/gv1 is replicated correctly to gfs2:/gv1 and gfs3:/gv1).

    client4 has an entry in its /etc/fstab file which reads:
    "gfs1:gv1  /data/gv1  glusterfs  defaults  0 2". This is also
    all working correctly (ie client4:/data/gv1/file1 is
    accessible and replicated).

    So, (and I haven't tested this yet) what happens to
    client4:/data/gv1/file1 when gfs1 fails (ie is turned off,
    crashes, etc)?

    Does client4 "automatically" switch to using one of the other
    two Gluster Nodes, or do I have something wrong in clients4's
    /etc/fstab file, or an error/mis-configuration somewhere else?

    I thought about setting some DNS entries along the lines of:

    ~~~

    glustercluster IN  A  192.168.0.1

    glustercluster  IN  A 192.168.0.2

    glustercluster  IN  A 192.168.0.3

    ~~~

    and having clients4's /etc/fstab file read:
    "glustercluster:gv1  /data/gv1  glusterfs defaults  0 2", but
    this is a Round-Robin DNS config and I'm not sure how Gluster
    treats this situation.

    So, if people could comment / point me in the correct
    direction I would really appreciate it - thanks.

    Dulux-Oz


    ________



    Community Meeting Calendar:

    Schedule -
    Every 2nd and 4th Tuesday at 14:30 IST / 09:00 UTC
    Bridge:https://meet.google.com/cpu-eiue-hvk
    Gluster-users mailing list
    Gluster-users@gluster.org
    https://lists.gluster.org/mailman/listinfo/gluster-users

    width=
    
<https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient>
        Virus-free.www.avast.com
    
<https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient>


    <#m_-4861399478586633768_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
    ________



    Community Meeting Calendar:

    Schedule -
    Every 2nd and 4th Tuesday at 14:30 IST / 09:00 UTC
    Bridge: https://meet.google.com/cpu-eiue-hvk
    Gluster-users mailing list
    Gluster-users@gluster.org
    https://lists.gluster.org/mailman/listinfo/gluster-users
________



Community Meeting Calendar:

Schedule -
Every 2nd and 4th Tuesday at 14:30 IST / 09:00 UTC
Bridge: https://meet.google.com/cpu-eiue-hvk
Gluster-users mailing list
Gluster-users@gluster.org
https://lists.gluster.org/mailman/listinfo/gluster-users

Reply via email to