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 <kna...@redhat.com
<mailto:kna...@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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