Re: RAC on linux

Oracle 9.2.0.2 RAC on RedHat 7.2 is "OK", but 7.2 has no support for CFS or AIO (As I remember - it has been a while. I switched to AS 2.1, still on raw devices, months ago.). It was in many respects the least problematic combination, but is, of course, not officially supported.

As far as the docs go, some are very good (RAC Concepts), some are marginally useful (e.g. RAC Setup and Configuration). Note that the CFS docs repeatedly mention "watchdog", even though it was discarded in 9.2.0.2 - months before CFS was even available. Other such contradictions abound... For example, no two docs seem to call the quorum disk the same thing - some call it that, some say the "cm" disk, some say other things. To keep things interesting, they sometimes rotate this usage between docs when a new version comes out. All quite confusing until you adapt by skimming over the details.

Don't even think about anything prior to 9.2.0.2 on any version of Linux - unless you actually want to do *A LOT* of jumping through flaming hoops - tweaking everything in sight, "faking the watchdog" (really - MetaLink even has detailed directions for "faking it"), diagnosing random node reboots, ad nauseum. My experience over the last year with RAC on Linux has been "entertaining", to say the least.

In 9.0.1.1, the Oracle-supplied cluster management software consisted of oracm (cluster monitor), oranm (network monitor), and watchdogd (daemon to randomly crash nodes ;-). Nodes spontaneously rebooted for no apparent reason - and took all the other nodes in the cluster down with them. This usually occurred at least a few times per week. ("It will be fixed in the next release".)

In 9.2.0.1 (I think - it might have been 9.0.x), they eliminated oranm. It was slightly more stable - only spontaneously, randomly, and for no apparent reason rebooting one node at a time (usually). ("It will be fixed in the next patchset.")

In 9.2.0.2, they eliminated watchdogd and added a kernel module named "hangcheck-timer". It became *much* more stable. I figure with the next release perhaps they will eliminate the last of the Oracle cluster management software troublemakers - oracm - and RAC will actually become as stable as it was initially hyped to be in 9.0.1 ;-)

All this was on a complete front-to-back Oracle "certified" configuration from a major vendor. [In hindsight, I should have been more suspicious when they used the "c" word so often and so loudly...]

Don Granaman (reluctant OCP)
OraSaurus resurrected

• Original Message ----- To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com> Sent: Sunday, February 02, 2003 5:23 PM

> Hello everyone, i've been quiet recently, for those of you who know what
> I've been up to class has been great, emergency medicine is really kewl.
>
> Now to the oracle stuff,
>
> We're having new requirements by multiple clients to ask about RAC(not
> necessarily on linux), so a couple of us thought, we'd try to implement
> it on a few linux servers, as an experiment to see how its done, etc.
>
> I'd really not purchase RH advanced Server 2.1 and just try it on rh
> 8.0, is this even possible?, I've got like no experience on the
> clustering side of operating systems.
>
> I've searched the OTN, oracle and RH sites to not much luck.
>
> Anyone tried this on non RH AS 2.1 and just used regular RH 8.0 and if
> so are you willing to share the good/bad and otherwise of your luck with
it?
>
> If there is something I missed in the docs on what I need to do to make
> it happen, point me that way and I'll be glad to read up on it.
>
> thanks, joe
>
>
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.net
> --
> Author: Joe Testa
> INET: jtesta_at_dmc-it.com
>
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-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: Don Granaman
  INET: granaman_at_cox.net

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