HA Configuration

nksharma74 · Wed Dec 19, 2012 7:14 am

Hello there,
I have configured a HA device using starwind. For my application I am connecting through SAN1. In case SAN1 fails then I need to change it to SAN2 instead of SAN1 and when SAN1 comes up then it would be changed again after sync. My questions are:

1.) Is this ok to work like this ? or is there a better way without having cluster ?
2.) I hope SAN1 would re-sync as soon as it come up ?

Regards, Naresh

Wed Dec 19, 2012 9:42 am

Hello there,

No, it doe`nt look OK, unfortunately. You need to connect to both SANs simultaneously (if the HA device is used of course). If you are using something else instead of HA devices I am strongly recommend to start using highly available storage.

nksharma74 · Wed Dec 19, 2012 1:43 pm

Anatoly (staff) wrote:Hello there,

No, it doe`nt look OK, unfortunately. You need to connect to both SANs simultaneously (if the HA device is used of course). If you are using something else instead of HA devices I am strongly recommend to start using highly available storage.

Thank you very much for your response. Thats right. I need to connect both the SANs simultaneously but what if any of these fails ? Shouldn't the other one function properly and re-sync the bad one when it gets changed ? Actually I am trying to setup 2 nodes with a HA device so that I reduce the downtime to minimum. Of course I am trying to to by pass clustering. So is there a way to achieve this kind of setup ?

Wed Dec 19, 2012 1:51 pm

what if any of these fails ? Shouldn't the other one function properly and re-sync the bad one when it gets changed ?

That is exactly how it should work. Can you confirm that you see such behavior in your system?
Here is some documentation that might be helpful for you:
http://www.starwindsoftware.com/starwin ... ng-started
http://www.starwindsoftware.com/starwin ... al-servers

nksharma74 · Wed Dec 19, 2012 2:25 pm

Anatoly (staff) wrote:
what if any of these fails ? Shouldn't the other one function properly and re-sync the bad one when it gets changed ?
That is exactly how it should work. Can you confirm that you see such behavior in your system?
Here is some documentation that might be helpful for you:
http://www.starwindsoftware.com/starwin ... ng-started
http://www.starwindsoftware.com/starwin ... al-servers

I had gone through these documents before coming here but these talk about clustering which I want to avoid !! I'm looking for cluster independent HA device.

Wed Dec 19, 2012 3:03 pm

I`m not sure that we are on the same page on this. Our HA device is independent from cluster: we dont need cluster, cluster needs us.
If you want to run HA without - feel free. Just note that if you need to more then one machine to use single HA device, then you need 3d party judgment software like DataPlow or MetaSan.

nksharma74 · Wed Dec 19, 2012 4:14 pm

Thanks Anatoly, perhaps I got the answer but I'm sure I'll be back with more

Fri Dec 21, 2012 12:02 pm

No problem!

I`ll wait for you here:)))

nksharma74 · Sat Dec 29, 2012 5:39 am

As promised I am back

, I have setup a HA device for 80gb. It worked fine for some time but next time when I switched on the machines, the iSCSI initiator kept on showing "reconnecting". I had a look at management console and found that the device was being sync'd so may be because of this device was not available !! Now I have following queries :

1.) Is HA device available when it is getting sync'd ?
2.) Is there any order to follow for machine shutdown to avoid repeated syncs ?
3.) Is there any how to available for trouble shooting ?

Regards, Naresh

nksharma74 · Thu Jan 03, 2013 3:27 pm

are my questions invalid ?

Wed Jan 09, 2013 1:12 pm

Sorry for the long response time - hollidays, you know

1.) Is HA device available when it is getting sync'd ?

Yes, the device is available. Only the target that is synchronizing is closing connections, while the opposite is not.

2.) Is there any order to follow for machine shutdown to avoid repeated syncs ?
3.) Is there any how to available for trouble shooting ?

I`ll sak you to clarify when exactly are you getting the unsynchronization.

Thank you

nksharma74 · Wed Jan 16, 2013 4:40 pm

Thanks Anatoly, I noticed few times that the HA device was not available after a reboot. When I had look at management console, I found it was getting syncd. Could you please explain "Only the target that is synchronizing is closing connections," ? How do I know which device is the target for sync ? I did shutdown both the machine so I guess both should be in sync !! That was the reason why I asked whether there is any shutdown order to keep both devices in sync ?

Fri Jan 18, 2013 4:02 pm

I noticed few times that the HA device was not available after a reboot. When I had look at management console, I found it was getting syncd. Could you please explain "Only the target that is synchronizing is closing connections," ? How do I know which device is the target for sync ? I did shutdown both the machine so I guess both should be in sync !! That was the reason why I asked whether there is any shutdown order to keep both devices in sync ?

target=one of the HA mirrors when talking about High Availability device.
The target that is synchronizing (receiving data from partner) will have corresponding mark in the SW Mgmt console.
If you shut down both machines that basically means that all entire storage went down, which means that it will be offline and definitely not in sync. If you need to shut anything down storage nodes for, lets say, maintenance, you need to shut down one server at the time.