4:54 a.m.
Hi,
Can you point me to some document that help me to understand how gluster
client work ?
Related to ovirt will be helpful.
Thanks,
~Rohit
On Thu, May 18, 2017 at 11:54 AM, knarra <knarra(a)redhat.com> wrote:
On 05/18/2017 10:35 AM, TranceWorldLogic . wrote:
Thanks,
Would you also explain about my 2nd question ?
let say hostB mounted glusterFS partition by using backup vol (e.g. hostB)
and after some time Host A come online, will GlusterFS client (mount)
automatically switch to Host A ?
mount will not switch automatically to Host A .
In an ideal case i.e with out using backup-vol-file-server option if host
B goes down, you mount will not be accessible since host B went down and df
-TH or mount does not show the volume or it says "Transport End point not
connected".
Take the case where using backup-volfile-server option. If host B goes
down, your mount will still be accessible since there is
backup-volfile-server and df -TH or mount still shows that volume is
mounted using Host B, but all the internal requests will be served through
Host A.
On Thu, May 18, 2017 at 9:43 AM, knarra <knarra(a)redhat.com> wrote:
> Hi,
>
> backup-volfile-servers is mainly used to avoid SPOF. For example take
> a scenario where you have Host A and Host B and when you try to mount a
> glusterfs volume using Host A with backup-volfile-servers specified, if
> Host A is not accessible, mount will happen with Host B which is specified
> in backup-volfile-server. backup-volfile-servers are mainly used to fetch
> the volfile from gluster and has nothing to do with data sync.
>
> data syncing comes as part of replicate feature in glusterfs where
> say for example, you have two Hosts Host A and Host B with replica volume
> configured, if Host A goes down for sometime, all the writes happens on
> Host B and when Host A comes up data gets synced to HostA.
>
> Hope this helps !!!!
>
> Thanks
> kasturi
>
>
> On 05/17/2017 11:31 PM, TranceWorldLogic . wrote:
>
> Hi,
>
> Before trying out, I want to understand how glusterfs will react for
> below scenario.
> Please help me.
>
> Let consider I have two host hostA and hostB
> I have setup replica volume on hostA and hostB. (consider as storage
> domain for DATA in ovirt).
> I have configure data domain mount command with backup server option
> (backup-volfile-server) as hostB (I mean main server as hostA and backup as
> hostB)
>
> 1> As I understood, VDSM execute mount command on both hostA and
> hostB.(for creating data domain)
> 2> That mean, HostB glusterFS CLIENT will communicate with main server
> (hostA).
> (Please correct me if I am wrong here.)
> 3> Let say HostA got down (say shutdown, power off scenario)
> 4> Due to backup option I will have data domain available on HostB.
> (Now glusterFS CLIENT on HostB will start communicating with HostB
> GlusterFS SERVER).
> 5> Now let say HostA comes up.
> 6> Will it sync all data from HostB to HostA glusterFS server ?
> (as per doc, yes, i not tried yet, want to confirm my understanding)
> 7> Will glusterFS CLIENT on HostB start communicate with main server
> (HostA) ?
>
> Please let me know, I am new to glusterFS.
>
> Thanks,
> ~Rohit
>
>
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