Running RAC in a Virtual Environment

I was in a discussion at an Oracle Meetup this week, and the subject of RAC in a virtualized environment – specifically Oracle Virtual Machine (OVM) – came up.
Here’s a couple of points which were discussed.

pingtarget

There was a lack of awareness of a common problem, which has a solution built-in to Oracle 12.1.0.2 Grid Infrastructure and later. In a virtualized environment, the network components are also virtualized. Sometimes, network failures on the host may not be raised up to the guests. As a result, the guest O/S commands can fail to detect the network failures and the Virtual NIC remains up. Grid Infrastructure (GI) will not perform a VIP fail-over as it can’t see the failure despite the network being unavailable.

To resolve this, Oracle has added an option of a “pingtarget” for each public network defined in GI. This will perform a keep-alive to a external device, usually something like the default gateway. This is just like the heartbeat on the cluster interconnect.

Before

srvctl config network

Network 1 exists

Subnet IPv4: 192.168.0.160/255.255.255.224/eth1, static
Subnet IPv6:
Ping Targets:
Network is enabled
Network is individually enabled on nodes:
Network is individually disabled on nodes:

The default gateway makes a good ping target. For this IP and subnet, it’s 192.168.0.161

srvctl modify network -k 1 -pingtarget 192.168.0.161

After

srvctl config network

Network 1 exists

Subnet IPv4: 192.168.0.160/255.255.255.224/eth1, static
Subnet IPv6:
Ping Targets: 192.168.0.161
Network is enabled
Network is individually enabled on nodes:
Network is individually disabled on nodes:

All safe!

Server Pools

A second item we discussed was the Server Pools in OVM. Each RAC guest should be on a different host, otherwise you have not eliminated that as a Single Point Of Failure. A second less obvious SPOF is the Server Pool disk.

A Server Pool is a filesystem LUN (and IP address prior to release 3.4) used to group a logical collection of servers with similar CPU models, within which we can create and migrate VM guests. For a RAC installation, each RAC node should be within a different server pool, as well as on different physical hardware.

ovs

In this image, RAC nodes within the same cluster should be created within each server pool. This configuration can safely support a 2 node cluster despite having 4 servers, with one node created in “OVS-Pool-2” on server “ovs02“. The second node should be in “OVS-Pool-1″ and can be on “ovs01“, “ovs11” or “ovs12“.

It is possible to live migrate guests between these 3 servers.

 

 

 

 

 

UKOUG Technology Day

northerntech17-com-600x110-rn-v2

We have organized a UKOUG Technology Summit in Leeds on 16th May.

It’s really a small Conference!

This is available to UKOUG Members and will cost 1 SIG Pass – even Bronze memberships come with 1 SIG pass, so all members could attend at no cost.
Non-members can pay to attend, but you should take out a Bronze Membership instead as it’s about the same price!

Come along, network with your peers, and listen to some amazing talks about all aspects of the Oracle technology product set; the Database, RAC, Engineered Systems, Development, Apex, DevOps, Solaris 11.4!, and more. Learn how Oracle interacts and works with Kubernetes, Docker, Apache Kafka, Apache Impala, Chatbots, and  just about everything else! 30 amazing talks!

Plus a keynote address from Oracle Executive John Abel and a social afterwards too!

All that, just 2 hours from London on the train!

You can find the Agenda here 

northerntech17-agenda

 

 

UKOUG Member Advocate: sorted!

I received an email from the UKOUG last week.

winners-picture

 

It turns out that I have won the vote to become the next Member Advocate for the UKOUG. I will (eventually) be joined on the board by Martin Widlake – who won the vote for the position of President Elect – a position whereby Martin will shadow the current UKOUG President before taking office on the Board. He has written about it here.

I would very much like to thank everyone who voted for me. I hope I can live up to your expectations. If you did not vote for me, that’s OK – I’ll represent you and your interests just the same as everybody else! Looks like I’m going to have to spend time getting up to speed with the Apps community, and re-acquainting myself with my old JDE friends.

Here’s to moving the User Group forward to meet the challenges of the changing face of our industry. See you all soon, and Cheers Everyone!

(sorry – would have posted this sooner but I was at the OUG Ireland User Group giving a couple of presentations and taking part in a Q&A panel about “18c and everything else!” – fantastic conference and lovely people there!)

 

 

UKOUG M.A. Voting Hots Up!

It’s getting hotter!

After many years volunteering at the UKOUG I am standing to be the Member Advocate at the UKOUG, representing the members on the board.

Do you think I will represent the membership well? Yes. VOTE FOR ME!

Oh, you must be the main UKOUG membership contact, or know who is, to vote.

giphy

One twist in the election is that Steve Davis has withdrawn from the vote due to business commitments, leaving a straightforward race between myself and Andy Nellis. That’s a shame as I think Steve would have made a good Member Advocate had he been voted in. Andy is unknown to me so I cannot comment on his suitability as a UKOUG volunteer or board member.

I’d really appreciate your vote – I know that many of you have voted for me already, but I want ALL of you to give me a strong mandate to improve the user group.

VOTE HERE

 

 

I want your vote!

Are you a member of the UKOUG? Read on…

ukoug_logo

I’m currently standing for the role of Member Advocate. But why?

I’ve been volunteering at the UKOUG for over 10 years, and speaking at the conferences and SIGs for the last 5 years or so.  I’ve been deputy chairing or chairing a SIG for all of this time and I’m currently the RAC SIG Chairperson. I’m also involved with our main conference, having helped on the organizing committees for several years, I organized the database stream for Tech16 and the entire content for Tech17. I enjoy giving back to the community and I think that by joining the board to serve as Member Advocate I will be able to further enhance the user group and the members experience. Your experience.

 

 

Feel free to tweet me, message me or comment if you have any questions!

Oh, and while you’re there, can you also vote for Martin Widlake to be President Elect. Nobody is running against him but the membership do need to confirm they are happy with his appointment. I’ve already voted for him!

ukoug-vote

twit1twit2twit3


OK, here’s a few testimonials from Twitter…I hope you will join the other UKOUG members in voting for me and Martin!twit4twit5

KILL! KILL! KILL! (of Unix processes)

The start of this isn’t my post – I got it from here: but I wanted to reblog/repost and enhance it because as far as I can tell, 99% of all known DBA’s only use kill -9 to remove unhappy processes.


Original Post:

Useless Use of Kill -9 form letter

No no no.  Don't use kill -9.

It doesn't give the process a chance to cleanly:

1) shut down socket connections

2) clean up temp files

3) inform its children that it is going away

4) reset its terminal characteristics

and so on and so on and so on.

Generally, send 15, and wait a second or two, and if that doesn't
work, send 2, and if that doesn't work, send 1.  If that doesn't,
REMOVE THE BINARY because the program is badly behaved!**

Don't use kill -9.  Don't bring out the combine harvester just to tidy
up the flower pot.

**don’t remove your Oracle or any other binaries please.


 

I hope you found that useful. I know I did. But what do the numbers mean? Well, they are increasingly violent ways to ask the program to stop itself. The command kill -9 isn’t asking the program to stop, it’s asking the O/S to stop running the program now, regardless of what it’s doing.

Run order of kills:

kill -15 : this is the equivalent of kill -sigterm and it the default. The program should terminate after it has finished what it is doing.

kill -2 : this is the equivalent of kill -sigint and is the same as pressing CTRL+C. This should mean “stop what you’re doing” — and it may or may not kill the program.

kill -1 : this is the equivalent of kill -sighup and tells the program that the user has disconnected. (e.g. SSH session or terminal window was closed). It usually results in a graceful shutdown of the program.

The executing program needs to be coded to recognise these kill signals, and all good software will spot them.

The other fun kill command is kill -sigstop. This can’t be blocked (like -9) as it’s an O/S level command too, but freezes the program execution like pressing CTRL+Z. You can continue the program execution later using kill -sigcont.

Oracle ACE Director

I was at UKOUG Tech17 this week in my capacity at both Speaker and Tech Lead (organizing and selecting the agenda, drinks, parties, etc – although the heavy lifting is done by the @UKOUG office)

There was rather a nice surprise waiting for me. Jennifer from the Oracle ACE Program upgraded my Oracle ACE to Oracle ACE Director.

ACED_blk

This is a wonderful honour and reflects the many many days dedicated each year to the Oracle community through presenting at conferences around the world, helping on forums, writing magazine articles, arranging SIG’s and meetups, as well as the aforementioned Tech Lead at #UKOUG_TECH17 

Thank you Oracle ACE Program!

 

As for Tech17? Here’s a few images of this year’s event!

This slideshow requires JavaScript.

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