RE: Oracle Parallel Server / Other HA Solutions

Ross, Dick, Jay, and even Jared,

   Thank you for your input on this subject. I am familiar with the documents written by Lawrence To, and recommendations for achieving higher percentages of expected uptime, and reducing MTTR. My particular division of GE Capital does indeed have a limited budget. Certainly an investment in the hardware to support OPS is less than the $ to implement hot standby and is less than the $ to have a hot site at a remote location. (We are more or less indifferent to Oracle software costs). Our platform is on Sun equipment. We use Veritas as our Volume Manager and Legato to manage our backups. (These things have made my DBA job fairly sweet.) For me, the only time (in 3 years) the disks were "a point of failure" was when someone who had the root password mounted swap space on one of my production database filesystems. I recovered in about an hour because I had a cold backup from the night before, and the crumby old tape drive where my redo logs were stored did not fail me. We certainly want to do better than this with our 24/7 internet database. I had forgotten about the triple mirroring solution and will certainly entertain that one as a possibility. Personally I would stand to gain much from a successful OPS implementation if indeed my management selected it as part of the "total solution." But an unsuccessful, high-maintenance OPS implementation is something I would like to avoid. At this time the database is rather small (< 10 Gig) and so it would be difficult to measure the advantages of investing in additional storage arrays (beyond the mirrored arrays we already have) to reduce MTTR. Certainly something that will go a long way for us is to tightly control who gets the root password. That problem has caused more angst here than any "hardware failures."

Thanks again for your responses. I have forwarded everything to my sysadmin.

Mary

-----Original Message-----
From: Mohan, Ross
Sent: Friday, October 13, 2000 10:41 AM
To: Multiple recipients of list ORACLE-L Subject: RE: Oracle Parallel Server / Other HA Solutions

I have to say this "disk is a single point of failure" is jangling to the cognitive logic subsystem.

Why?

Well, the disk farms i have seen have redundant controllers, with redundant channels, TRIPLE power supplies, at least a single mirror with dual porting. There's your "single" disk point of failure for you.

Now, try this: Take your two "redundant" nodes....put them in a really really big rack and then inside ONE big box. <G>

Are the two nodes ( which now have at least redundant CPUs, power supplies, etc. ) a "single point of failure"?

Come on, guys, if you've worked with this stuff a bunch you know:

(a) properly configured diskfarms have a great MTBF, better

        than the other hardware, and
(b) to REALLY answer Mary's class of questions, you need to

        calculate MTBFs and MTTRs.

The rest is armchair clustering!

hope this pertains,

Ross Mohan

p.s. HA is the latest marketspeak for "failover" or "redundant" or whatever...
please try to browse a copy of "In Search of Clusters" by Gregory Pfister from
IBM. It's a cult classic, a helluva fun read, and one of the best thought-out
technical books i have ever seen, period.

-----Original Message-----
Sent: Thursday, October 12, 2000 2:00 PM To: Multiple recipients of list ORACLE-L

Mary,

OPS is not an HA solution. While you may still have an instance running if a node goes down, the storage medium is still a single point of failure.

Jared

On Thu, 12 Oct 2000, Ruiz, Mary A (CAP, CDI) wrote:

> I need a little advice. We have a fairly new (< 1 year) 8.1.5 instance
to
> support my company's internet business. We recently changed our network
> solutions provider and now my management wants to achieve a higher level
of
> redundancy than it currently does with mirrored disks. The solution being
> proposed by my Sysadmin is an Oracle Parallel Server solution. Some
> background is in order here - we have always shut our databases down at
> night for backups. I am not highly skilled in backup and recovery
although
> I tried some of the hot backup techniques from this list and was able to
> recover successfully to another server. I noticed that the course offered
> by Oracle in OPS has backup and recovery as well as performance tuning as
> pre-requisites, which indicates to me that OPS could be extremely
> challenging. Also, I have read mainly unfavorable comments about OPS from
> this list, but most of those comments were based on the Oracle 7
> implementations (High administrative costs, difficult to implement, etc.).

>
> Have things improved with Oracle 8i ? Is OPS worth pursuing? Or should I
> convince my management that extra $$ spent in, say, a hot standby database
> is well worth it? Is there any other solution that would not involve a
> second set of disks, rather a second database on the same set of disks ??
>
> Thanks in advance,
> Mary Ruiz / Atlanta
>
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.com
> --
> Author: Ruiz, Mary A (CAP, CDI)
> INET: Mary.Ruiz_at_gecapital.com
>
> Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
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Jared Still
Certified Oracle DBA and Part Time Perl Evangelist ;-) Regence BlueCross BlueShield of Oregon
jkstill_at_bcbso.com - Work - preferred address jkstill_at_teleport.com - private

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Author: Mohan, Ross
  INET: Ross.Mohan_at_PictureVision.com

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