[ovirt-users] Terribly slow web consile post migration of oVirt Engine from one host to another host
Anantha Raghava
raghav at exzatechconsulting.com
Thu Jun 9 13:51:10 EDT 2016
Hi,
We need to understand Postgress backup & restore process to understand
these properly. Not having such an expertise with Postgress.
Any way, interesting discussions..worth spending time to understand it
properly. That answers many questions....
--
Thanks & Regards,
Anantha Raghava
On Thursday 09 June 2016 06:41 PM, Yedidyah Bar David wrote:
> On Thu, Jun 9, 2016 at 3:33 PM, Anantha Raghava
> <raghav at exzatechconsulting.com> wrote:
>> Hi,
>>
>> Thanks for taking time and reverting back to me.
>>
>> I have seen this explanation from engine-backup help and realise that it is
>> something to do with Postgres DB restore activity. But not much said about
>> it. I feel it instructs Postgress DB to restore the DB without privileges
>> with which the object was created, but use new permissions & privileges
>> passed along with --change-db-credentials and others passed during
>> engine-backup --mode=restore.
> Exactly.
>
> And if you do not pass --change-db-credentials, you'll simply get the
> default, which is to just give permissions to the user creating the
> schema.
>
> Bottom line: If you used only defaults, and did not create users
> and give them grants, there is no difference between the options.
> They'll create the exact same database. If you did add grants, you
> must choose.
>
> I agree it's not very user-friendly to require choice, but please
> take into consideration that if you had a large setup (say hundreds
> of VMs or more) with dwh history included over some time, you'll have
> a large database, and I think it will be much less friendly if we
> "just try" restoring (which can take several hours then) and fail
> in the end due to missing users.
>
> Please also see the discussion on these bugs for more details:
>
> https://bugzilla.redhat.com/show_bug.cgi?id=1217402
> https://bugzilla.redhat.com/show_bug.cgi?id=1220791
>
> Best,
>
>> However not sure.
>>
>> --
>>
>> Thanks & Regards,
>>
>> Anantha Raghava
>> On Thursday 09 June 2016 05:47 PM, Alexander Wels wrote:
>>
>> On Thursday, June 09, 2016 12:28:41 PM Anantha Raghava wrote:
>>
>> Hello Alexander,
>>
>> You are right. The FQDN was the culprit. Once I entered the FQDN in
>> /etc/hosts file, the problem got resolved.
>>
>> Thanks for your guidance.
>>
>> By the way any document that explains what is --restore-permissions in
>> engine-backup process?
>>
>> If you type engine-backup --help you will get a list and explanation of all
>> the possible options.
>>
>> Affects only the custom dump format. Will not pass to pg_restore '--no-owner
>> --
>> no-privileges'. Might not work as expected with the --*db-user options.
>>
>> Is what the --help says, not sure what that means though.
>>
>> Hi,
>>
>> I will try both options tomorrow & revert back here.
>>
>> Regards,
>> Anantha Raghava
>>
>> On Jun 8, 2016 10:04 PM, "Alexander Wels" <awels at redhat.com
>>
>> <mailto:awels at redhat.com>> wrote:
>> On Wednesday, June 08, 2016 08:49:16 PM Anantha Raghava wrote:
>> > Hi,
>> >
>> > I was able to migrate the oVirt Engine from one host to another
>>
>> using
>>
>> > engine-backup utility. On the new host, the data is loaded
>>
>> properly but
>>
>> > the Administration Portal is terribly slow.
>> >
>> > It take about 2 to 3 minutes to allow me to enter user name &
>>
>> password.
>>
>> > Once logged in, it takes hell a lot of time to show up the data.
>>
>> Click
>>
>> > on a tab, we need to wait for a good amount of time to see the
>>
>> actual
>>
>> > data. Even the refresh is taking time to execute although it is
>>
>> set to 5
>>
>> > Seconds.
>> >
>> > But if I enable old server and connect, every thing works quickly.
>> >
>> > Note:
>> >
>> > 1. We do not have DNS in our environment.
>> > 2. Engine name & even the IP is retained the same.
>> > 3. Before migration, we stopped ovirt-engine on old server, took the
>> > backup, shutdown & disconnected the old server.
>> > 4. We installed the ovirt-engine on new server, run engine
>>
>> setup, noted
>>
>> > down the DB password, did engine-cleanup, restored the data using
>> > engine-backup utility and executed engine-setup again. It did
>>
>> recognize
>>
>> > restored data and only httpd configuration was sought and we
>>
>> selected
>>
>> > the defaults.
>>
>> It is highly likely 1 of 2 things:
>>
>> 1. The entropy mentioned by Brett, however that is mostly
>> applicable on hosted
>> engine as VMs don't usually have good entropy.
>> 2. The engine cannot resolve itself (which looking at your
>> description is the
>> likely culprit). Since you don't have DNS, you need to add the fqdn to
>> /etc/hosts so it can resolve itself.
>>
>> > Result is terribly slow Web Console.
>> >
>> > First, we attempted to setup ovirt-reports and later removed it
>>
>> thinking
>>
>> > that may be slowing down the engine server. Yet the same result.
>> >
>> > Commands used to backup from old server: "engine-backup
>>
>> --mode=backup
>>
>> > --file=<filename> --log=<log file name> --provision-db"
>> > Command used to restore on new server: "engine-backup --mode=restore
>> > --file=<backup-file-name> --log=<log-file-name>
>>
>> --change-db-credentials
>>
>> > --db-host=localhost --db-user=engine --db-name=engine
>> > --db-password=<password noted down in step 4>
>>
>> --no-restore-permissions"
>>
>> > The command executed without any errors, resulting in a terribly
>>
>> slow
>>
>> > web console.
>> >
>> > Note: Without --restore-permissions, the restore fails. Did not
>> > understand what to give as restore permissions. Hence used
>> > --no-restore-permissions.
>> >
>> > *Hardware configuration:*
>> > *
>> > **Old Server:* i3 Processor, 4 GB Memory, 1 Gbps NIC
>> > *New Server :* Lenovo x3250 M5 Server with Intel Xeon Processor,
>>
>> 16 GB
>>
>> > RAM, 2 X 1 Gbps NIC.
>> >
>> > Just unable to understand why it is terribly slow.
>>
>>
>>
>> _______________________________________________
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>> Users at ovirt.org
>> http://lists.ovirt.org/mailman/listinfo/users
>>
>
>
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