Please be aware that the SAP SQL Anywhere Forum will be shut down on August 29th, 2024 when all it's content will be migrated to the SAP Community.


I'd like to test my HA system. What is the "recommended" way to "crash" a server to do so? A dbstop is a "controlled shutdown" and might not be a "real" test. I suppose I can use (under Windows) Task Manager to kill the process but how would I identify which process is the Primary server (for a specific db)?

Thank you.

asked 09 Apr '17, 10:15

AlK's gravatar image

accept rate: 37%

Are you running the 3 HA servers on different hardware? (Then dropping network cables might be quite realistic). Otherwise, besides knowing which server is which by using a fitting server name, you can query the relevant properties of a running server instance via, say

select property('ServerName'), property('TcpIpAddresses'), property('ProcessId'), db_property('MirrorRole')

The process id might be helpful to kill the process via OS tools.

Note, dbstop can be used with -y to drop current connections.

permanent link

answered 10 Apr '17, 03:15

Volker%20Barth's gravatar image

Volker Barth
accept rate: 34%

converted 16 Apr '17, 15:28

Hi Volker,

Thanks for the hint about select ... property('ProcessId') ... That's exactly what would be needed in a Ubuntu environment! That's the answer! (Once again, I'm missing something about this forum. I apparently can mark my (this) own comment as the answer but I can't do so with your comment which is the actual statement of the answer!)

(15 Apr '17, 19:53) AlK
Replies hidden

Once again, I'm missing something about this forum...

No, you're not missing anything... - When I'm not sure whether I have a "real answer" or just some hints, I usually respond with a comment, as in this case. When you tell that you do consider that an answer, feel free to tell so (just as you have done), and others or me can easily turn the comment into an answer... - and you might be able to do as well once you got more reputation points...

(18 Apr '17, 02:50) Volker Barth

The High Availability feature only cares about "availability" which translates to connections between servers.

For example, if the primary server loses connectivity to secondary (mirror) and the arbiter, two things happen: (a) the primary drops all client connections because doesn't have a connection to either of the secondary or mirror, and (b) the arbiter and secondary agree (quorum) that the old primary is unavailable and therefore the secondary becomes the new primary (failover). If the old primary database is restarted, it will become the new secondary... unless CREATE MIRROR ... AS PARTNER ... preferred = 'YES' in which case a second failover will be forced and the old primary/new secondary immediately becomes the new primary again (thus annoying all the users a second time :)

The following are equivalent ways of making an HA server unavailable: kick the power cord out of the UPS, run dbstop, End Task in Task Manager, run taskkill, pull the ethernet cable, and so on.

I think Volker's suggestion mirror_role = 'primary' or 'mirror' and ProcessId is the way to identify which is which. Another way is to use Foxhound with connections to each partner directly, or to the primary and secondary, or all four :)

permanent link

answered 10 Apr '17, 08:05

Breck%20Carter's gravatar image

Breck Carter
accept rate: 20%

and therefore the secondary becomes the new primary (failover).

One might add that an automatic failover requires synchronous mode or the mirror option "auto_failover" = On.

(10 Apr '17, 08:15) Volker Barth
Replies hidden

Thanks to both Breck & Volker for helpful hints!

(15 Apr '17, 19:56) AlK
Your answer
toggle preview

Follow this question

By Email:

Once you sign in you will be able to subscribe for any updates here



Answers and Comments

Markdown Basics

  • *italic* or _italic_
  • **bold** or __bold__
  • link:[text]( "title")
  • image?![alt text](/path/img.jpg "title")
  • numbered list: 1. Foo 2. Bar
  • to add a line break simply add two spaces to where you would like the new line to be.
  • basic HTML tags are also supported

Question tags:


question asked: 09 Apr '17, 10:15

question was seen: 1,686 times

last updated: 18 Apr '17, 02:50