[ovirt-users] Terribly slow web consile post migration of oVirt Engine from one host to another host

[Alexander Wels]

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.