Re: Oracle and Solstice DiskSuite

Chase Hacker wrote:
>
> Hi guys.
>
> We've just made some very interesting findings concerning the use
> of Solstice DiskSuite with oracle. It seems that the added layer
> of devices confuses oracle greatly, and periodically causes the system
> to go into a state where it is basically CPU bound, doing little to
> no I/O work. This in turn causes the load average to spike (like to
> the 20-25 mark) and processing to generally grind down slowly.
>
> This problem has been seemingly baffling us for several weeks. We've
> had Oracle and Sun's best tekkies in here trying to figure it out.
>
> First Oracle says it needs more memory. Then more processors.
> Sun points the finger back and says it's not the problem.
>
> By the way, this is Oracle 7.2.2 running on a SPARCCenter 2000E with
> 768Megs of memory, and 6 processors.
>
> The application is an OLTP call-center application, currently running
> a maximum of about 175 users.
>
> Has anyone else seen or heard of such a problem with the combination
> of SDS and Oracle?
>
> By the way, we sorta stumbled upon this when we decided to run the
> stress test on our development server, which is not doing SDS mirroring.
> The production server has 2 18Gbyte Sparc Storage Arrays, each the
> complement mirror of the other.
>
> Any ideas?/Comments?
>
> Thanks!
>
> Please e-mail to chase.hacker_at_mci.com
We are looking at installing a similar set up so I would be interested in hearing of any conclusions you come to.

We are only planning to use mirroring and no RAID 5.

One thing that we were wondering about: would the ufs journalling be useful in such a setup? Since ORACLE is already journalling the data via redo logs, would the disksuite journalling just be added overhead? Also, would large file operations cause the journalling to really slow down performance? (Since it would initially try to log the changes to the journal, find it doesn't have enough room, then have to do the actual write.)

So I guess my comment would be: Are you using the disksuite journalling feature? If so, does turning it off have any effect?

-- 
Rob Allan                       |  rob.e.allan_at_hydro.on.ca
Ontario Hydro                   |  Tel. (416) 592 4195
Toronto, Ontario, Canada        |  Fax  (416) 592 4966