Re: Semaphores Shared memory in Solaris

"Sybrand Bakker" <postbus_at_sybrandb.demon.nl> ha scritto nel messaggio news:trp73e8aubpu34_at_news.demon.nl...
>
> "Alessandro Deledda" <adeledda_at_it.tiscali.com> wrote in message
> news:9ph2f2$kck$1_at_pegasus.tiscalinet.it...
> > What is the right semaphores/shared memory settings for a Sun Enterprise
> > cluster E6500 with 2 nodes, 10 logical hosts with 10 Oracle Enterprise
> > Edition 8.1.6 installed and 1 instance for each installation?
> >
> > RAM 20G
> > initparameter processes = 400 for each DB
> > SGA for each instance is about 1G;
> > Sun Solaris 2.6;
> >
> > Oracle formula says:
> > Instance A = 100 processes
> > Instance B = 100 processes
> > Instance C = 200 precesses
> > SEMMNS=((A=100) + (B=100)) +((C=200)*2) + ((# of instances)*10)=630;
> > therefore in my case (400*10)+(400*2)+(10*10)=4900 , is it right?
> >
> > But these instances are concurrently and i have problems with shared
> memory.
> > shmmax >= SGA?
> > And if this is right what SGA i have to consider, total SGA of 10
instance
> > (1G*10) or single SGA of each instance (1G)?
> >
> > This is the result of my calculation but i'm not sure, Do you think it
is
> > right?
> >
> > set shmsys:shminfo_shmmax=4294967295
> > set shmsys:shminfo_shmmin=1
> > set shmsys:shminfo_shmmni=100
> > set shmsys:shminfo_shmseg=10
> > set semsys:seminfo_semmni=400
> > set semsys:seminfo_semmsl=400
> > set semsys:seminfo_semmns=5000
> > set semsys:seminfo_semopm=400
> > set semsys:seminfo_semvmx=32767
> >
> > I am very confused and i hope you help me, thanx in advance.
> >
> >
>
> Are you saying you have installed one and the same version of Oracle *10*
> times on *one single* server?
> For heaven's sake : WHY?
> One time would have been more than enough!!!!
>
> I'm not sure why you specify the number of processes for 4 instances and
> multiply that by then.
> Does that mean you have 40!!! instance running on one single server?
> Those 40 instances would go heavily competing for resources, and the
> performance will be abysmal.
> The correct formula is
> (the sum of the number of processes (which means processes in init.ora)
*2)
> plus (10 sempahores * the number of instances.
> If you have 4 instances running that would mean 440 semaphores.
> If you have 10 times as much instances running, multiply that by a factor
> 10.
>
> The amount of virtual memory required is the *sum of the sizes of the
> individual SGAs*
> The Oracle guideline is to limit that sum to one third of *physical*
memory.
>
> In short: I don't believe your setup is ever going to work, you need to
buy
> more servers or apply for the Guiness Book of Records.
>
> Hth,
>
> Sybrand Bakker, Senior Oracle DBA
>
>
>

Excuse me, i mean 10 instance of 8.1.6; 10 logical hosts for maintain separate these instances with 10 separate listener. In short:

Server E6500.
20G RAM.
Solaris 2.6.
Oracle 8.1.6.
10 Instances with 400 processes for each one. SGA about 1G for any DB.

(the sum of the number of processes (which means processes in init.ora) *2)  plus (10 sempahores * the number of instances in my case = 4900. (ok for semaphores)
but for shared memory?
shmmax = about 10 gig (1G * 10 instance)?

I thought shmmax sized for max SGA size. So if my max is 1 gig I would size them at least 1 gig if not 2. I don't want the SGAs being split if possible. Received on Fri Oct 05 2001 - 02:51:06 CDT