Configure Server Roles for HA

[tsuliman]

How do you configure the server roles for HA on applogic ?
or is it just a matter of having more than 2 servers 1 controller and 2 nodes
So my question is this just HW dependent operation and applogic will enable HA if we have number of servers on the grid or is there some thing that we need to run to enable that feature in addition to have those servers added to the grid

because that what I concluded based on the message Application HA check failed: There are not enough available resources to restart components running on 1 server [srv1].

the document here on this link doesnt give you really clear information or I just may be overlooked some thing

http://doc.3tera.com/AppLogic27/High-Availability.html

and the command ha has only 2 options available

ha Object

Method


Description

info


Display high availability information


>ha check
Retrieving system information...
Checking HA state of applications...
checking for degraded volumes...
checking if components can be rescheduled...
Application HA check failed: There are not enough available resources to restart components running on 1 server [srv1].
Checking HA state of grid controller...
Checking HA state of networks...
grid6> ha info
HA State : unavailable
Application HA State : unavailable
Controller HA State : ok
Backbone Network HA State : disabled
External Network HA State : disabled

grid6> srv list
Name State CPU Mem(MB) BW(Mbps) Role
Alloc Free Alloc Free Alloc Free
---------------------------------------------------------------------
srv1 up 7.90 0.00 26176 4594 1189 810 primary
srv2 up 0.00 8.00 0 15610 0 2000 secondary
srv3 up 0.50 3.50 288 7227 72 1927 secondary

[tsuliman]

I guess we need to add more resources for the application and permissions need to be adjusted to run the grid set command
grid set ha_network=1
Network HA-related settings may only be modified by a grid maintainer.

grid6> grid set ha_network=1
Network HA-related settings may only be modified by a grid maintainer.
grid6> grid set ha_external=1
Network HA-related settings may only be modified by a grid maintainer.

[PeterNic]

tsuliman,

There are several aspects of HA that AppLogic maintains.

1. With respect for volumes, as long as you have more than 1 server, volumes will be mirrored (unless the volume is created as non-mirrored; use vol info to check if a volume is mirrored and whether the mirror is in sync ).
2. With respect to applications/appliances, as long as you have more than 1 server and available resources, appliances will get restarted if a server fails (esp. if you also configure IPMI during grid setup) [the HA check failed message you got indicates there are not enough resources to restart components or volume mirrors are broken]
3. With respect to the grid controller, AppLogic will automatically assign up to two secondary servers. Minimum of 3 servers are required for proper controller failover, as long as IPMI power control to be configured.
4. With respect to network high availability, AppLogic enables this automatically during installation if you provide the needed number of NICs and switches. In general, it is not necessary to use the "grid set" commands to configure network HA (these commands are for troubleshooting)

Let me know if this helps

Best regards,
- Peter

[tsuliman]

So here what I did

1. I used vol info to check the mirroring and the sync

Find out if there are any degraded volumes that have their only good stream/mirror on the failing server.

Execute vol list server=srvX and note all degraded volumes
For each degraded volume, execute vol info volume-name and note any volume that has its only good mirror on the failing server.

Most of the applications have mirrored volumes except the one below I havent check the other servers but there might be some that are not mirrored is this the correct approach ?

volume list bak_filer_pass1 --verbose
Name Size(MB) Server State Filesystem Mirrored Mount State Link Comment
-------------------------------------------------------------------------------------
apk_volume 300 srv1 ok ntfs03 N available N
iso_volume1 1794 srv1,srv2 ok iso9660 Y available N
wmware_volume 45 srv1 ok iso9660 N available N

Would that be the reason ???

what option on vol info to use to check for the sync???


SO regarding the last commetents we dont have the power network setup so are u suggesting that this could be the reason or some thing else excuse me if I overlooked some thing ????

We have 3 servers on this grid 1 controller and 2 secondary

[PeterNic]

The primary/secondary roles, the IPMI power network and the network HA configuration all have no impact on volume mirroring at all. For as long as you have 2+ servers, new volumes will be mirrored.

There are two ways in which non-mirrored volumes could have been created:
- create the volume when the grid has only one server
- create the volume with mirrored=0 option

Volumes that are created as non-mirrored are not considered degraded. The only way to see them all is to run "vol list --all" and see which ones have "N" in the "mirrored" column. (It may be easier to actually use "vol list --all --batch" and grep the output for mirrored=0.)

Off the top of my head, the only way to change the mirroring attribute of a volume is to copy it. For example, the get a mirrored version of the apk_volume, you would do:

vol rename apk_volume apk_volume0
vol copy apk_volume0 apk_volume
vol destroy apk_volume0



This will create a mirrored version of the volume; it will be also in good repair, so you will not have to repair the mirrors.


NOTE: please make sure the volume was copied OK before deleting the old volume; you can also keep the old volume for a couple of weeks, just in case.

Does this help?
- Peter

[PeterNic]

(Oh, for the commands to work in your case, you will likely have to do "ca bak_filer_pass1" in order to set bak_filer_pass1 as a current application before executing the volume commands)