Config for BIG server (Solaris)

Question

Our app is currently running pretty well on 2-cpu NT servers. But we need
more performance to support more users on one instance of WL (clustering
isn't yet an option), so we are trying a Big Solaris server. We're looking
for any pointers on how to configure WebLogic/JVM for a big server, esp.
Solaris. I've read over some of the Sun docs but am still not sure.
Server: 8-processor, 6G memory, Solaris 2.7, JDK 1.3.0_03, WL 5.1 sp9
Heap size: should we set -Xms -Xmx=4.5G on this box?? (was 780M on 1G NT)
Most things say to set the heap "large" but too big can cause problems.
What's as big as possible with 8 processors?
#execute threads: should we multiply because of the number of processors?
We had been using 30 on 2-processor NT - should we now use like 100?
There's some other JVM params that we may play with as well, including the
HotSpot options that are listed on the WL site. Should we set -XX:NewSize
(and Max) = 128M, 256M, higher?
Additional info: our application has many EJBs (Entity and Stateless
Session) being accessed by client applets and JSPs. Our total number of
users will be in the hundreds, even under heavy loads, but they cause a lot
of activity in the server. Any advice on these and other parameters is
appreciated.

Answer 1

Yes, I think 2GB memory for one JVM would be too much even with eight CPUs.
In most cases, I woud use 512m per instance, but I am sure there are several
good folks in this news group using more than that. They can share their
experience.
.raja
"Joe Herbers" <[email protected]> wrote in message
news:[email protected]...
So even with 8 processors, you think 2G is too big? We've initially
configured the JDK to use incremental garbage collection so that wewouldn't
see large pauses, though I'm not sure how much of a performance hit wetake
for that (I suppose we should try to benchmark it)
We've got 6G on this box so I hate not to use it, but if others have seen
this not work, then we'll try a smaller heap size (1G?) However, a doc on
the Sun site says these two things: "Unless you have problems with pauses,
try granting as much memory as possible to the JVM." "Be sure to increase
the memory as you increase the number of processors, since allocation canbe
parallelized, but GC is not parallel." I guess we should monitor GC times
at 2G to see how it's doing.
"Scott Simpson" <[email protected]> wrote in message
news:[email protected]...
You really don't want to make your heap so large. This is a very bad idea.
When the system garbage collects, it will have to go through gigabytes of
memory and your server will stop. Making your heap size too large is justas
bad as making it too small.
"Deyan D. Bektchiev" <[email protected]> wrote in message
news:[email protected]...
Joe,
Your first problem would be memmory since 1.3.0 has a limitation of 2GB
of
heap
per JVM (its actualy a little bit less 2010k worked for us) so you might
consider running more than one instance if memory would be a problem.
I'm
not
sure if they've lifted that to 4GB in 1.3.1 but it is going to be for
sure
for
1.4.0.
The number of execute threads solely depends on your application since
if
you
have a lot of I/O then you'd want to increase the number of executethreads
while if you are mainly using CPU cycles and most threads do not block
you
might
consider even reducing the number of execute threads.
Best way to find out what is best for you -- benchmark it.
--deajn
Joe Herbers wrote:
Our app is currently running pretty well on 2-cpu NT servers. But we
need
more performance to support more users on one instance of WL
(clustering
isn't yet an option), so we are trying a Big Solaris server. We'relooking
for any pointers on how to configure WebLogic/JVM for a big server,
esp.
Solaris. I've read over some of the Sun docs but am still not sure.
Server: 8-processor, 6G memory, Solaris 2.7, JDK 1.3.0_03, WL 5.1sp9
>>>
Heap size: should we set -Xms -Xmx=4.5G on this box?? (was 780M on 1GNT)
Most things say to set the heap "large" but too big can cause
problems.
What's as big as possible with 8 processors?
#execute threads: should we multiply because of the number ofprocessors?
We had been using 30 on 2-processor NT - should we now use like 100?
There's some other JVM params that we may play with as well, includingthe
HotSpot options that are listed on the WL site. Should weset -XX:NewSize
(and Max) = 128M, 256M, higher?
Additional info: our application has many EJBs (Entity and Stateless
Session) being accessed by client applets and JSPs. Our total number
of
users will be in the hundreds, even under heavy loads, but they causea
lot
of activity in the server. Any advice on these and other parameters
is
appreciated.