RH5.2(2.0.36) O8.0.5 Kernel Configuration Questions

Question

Looking for wisdom, insight, and a step-by-step procedure:
I have the CD-ROM from Oracle8 release 8.0.5 Standard Edition for
Linux, and I'm running Kernel 2.0.36 in a Red Hat 5.2
environment.
I'm working through the Installation Guide (referred to as the
"manual" in the following text). I'm in no hurry, and I would
rather get it right (even robust) the first time than get it
running as soon as possible. So, I'm trying to follow the
instructions. Here's what I've come up with so far; please post
your comments as replies here on technet.oracle.com:
1. The first instruction in the manual under Configure LINUX
Kernel for Oracle says "Use the ipcs command to obtain a list of
the system's current shared memory and semaphore segments, and
their identification number and owner." Specifically, what does
this mean that I am looking for?
# ipcs
------ Shared Memory Segments --------
key shmid owner perms bytes nattch
status
0x00000000 0 nobody 600 52228 11
dest
------ Semaphore Arrays --------
key semid owner perms nsems status
------ Message Queues --------
key msqid owner perms used-bytes messages
0x00000000 0 root 700 0 0
I did not find the man page on ipcs particularly enlightening.
2. In the next section, entitled, "Set the kernel parameters
corresponding to ...", I have gathered (though I wish the manual
said so explicitly) that these need to be set in the source for
the kernel and that the kernel would then need be recompiled.
(OK, end of whining, now onto the nitty gritty.) I have the
Shared Memory and Semaphore parameters in Table 2-2 and want to
plug them into the source.
First change needed, in file /usr/src/linux/include/linux/sem.h:
change #define SEMMSL 32 to #define SEMMSL 128
(I'll give a semaphore id 128 identifiers so that I can run 128
oracle processes. The max is 512 according to sem.h, so I took
the goemetric mean, since this is intended to be a test bed.)
I see no other changes needed in this file, and few implications
that I'm going to cause major problems with this change. On to
the next.
Second changes needed, in file
/usr/src/linux/include/asm-i368/shmparam.h:
Now, here's the part upon which I am really stumped.
change #define SHMMAX 0x2000000 to #define SHMMAX 0xFFFFFFFF
(I'm pretty sure that decimal 4294967295 is hex FFFFFFFF, though
the latter is a lot easier to write correctly!)
I looked up a few lines and read
SHMMAX <= (PAGE_SIZE << SHMIDX_BITS
Currently, PAGE_SIZE is set in
/usr/src/linux/include/asm-i368/page.h
to 1UL<<12 (0x1000).
However, SHMIDX_BITS + SHMID_BITS <= 24 from a few lines
above. And, from a few more lines above, SHMIDX_BITS is set to
15 and SHMID_BITS is set to 7. So, either I can tweak the two
BITS values or the PAGE_SIZE, right? (THIS IS NOT A RHETORICAL
QUESTION. I WOULD LIKE YOUR INPUT!).
However, to get SHMMAX to 2^32 with a page size of 2^12, I would
need SHMIDX_BITS set to 20, which would leave only 4 bits for
SHMID_BITS, which woud lin turn put SHMMNI at 16, which is too
low for the value recommended in the oracle manual, 100 (I wonder
if that is really 100 or if it is supposed to be 0x100...).
ANYway, It looks like I cannot do the whole job with SHM_BITS,
or even most of it.
This seems to lead me to adjusting page size, from 2^12 to 2^15.
To do this, I'll need to alter /usr/src/linux/mm/kmalloc.c in
order not to break the PAGESIZE-dependent structs. Does this make
sense?
Has anyone (even at Oracle...) done this level of analysis when
installing Oracle8 on Linux?
I saw that a few people have edited files, but few have mentioned
which files, and I have seen no details at all on the changes
made. Does this resemble the reasoning that they took?
Do I really have to change PAGE_SIZE to pull this off?
Do the instructions need to be changed? I think that they could
be a little more explicit, IMHO.
If you have read this far, thanks very much! I look forward to
your feedback.
null

Answer 1

I am really sorry that probably will not answer your questions,
but here is my advice:
use $ORACLE_HOME/bin/tstshm utility to find out
"Total shared memory attached"
if it is greater that the SGA size you expect then do nothing.
If it is not then change some of the parameters in the kernel.
If you need more information and you have a Technical Support
Contract you can call an analyst and get more datailed
information.
I'm sure at Oracle there is huge amount of resources about that.
Regards: Michael Daskaloff
P.S. Have in Mind that the default SHM parameters in RedHat 5.x
are good for a initial installation.
Art Eschenlauer (guest) wrote:
: Looking for wisdom, insight, and a step-by-step procedure:
: I have the CD-ROM from Oracle8 release 8.0.5 Standard Edition
for
: Linux, and I'm running Kernel 2.0.36 in a Red Hat 5.2
: environment.
: I'm working through the Installation Guide (referred to as the
: "manual" in the following text). I'm in no hurry, and I would
: rather get it right (even robust) the first time than get it
: running as soon as possible. So, I'm trying to follow the
: instructions. Here's what I've come up with so far; please
post
: your comments as replies here on technet.oracle.com:
: 1. The first instruction in the manual under Configure LINUX
: Kernel for Oracle says "Use the ipcs command to obtain a list
of
: the system's current shared memory and semaphore segments, and
: their identification number and owner." Specifically, what
does
: this mean that I am looking for?
: # ipcs
: ------ Shared Memory Segments --------
: key shmid owner perms bytes nattch
: status
: 0x00000000 0 nobody 600 52228 11
: dest
: ------ Semaphore Arrays --------
: key semid owner perms nsems status
: ------ Message Queues --------
: key msqid owner perms used-bytes messages
: 0x00000000 0 root 700 0 0
: I did not find the man page on ipcs particularly enlightening.
: 2. In the next section, entitled, "Set the kernel parameters
: corresponding to ...", I have gathered (though I wish the
manual
: said so explicitly) that these need to be set in the source for
: the kernel and that the kernel would then need be recompiled.
: (OK, end of whining, now onto the nitty gritty.) I have the
: Shared Memory and Semaphore parameters in Table 2-2 and want to
: plug them into the source.
: First change needed, in file
/usr/src/linux/include/linux/sem.h:
: change #define SEMMSL 32 to #define SEMMSL 128
: (I'll give a semaphore id 128 identifiers so that I can run 128
: oracle processes. The max is 512 according to sem.h, so I took
: the goemetric mean, since this is intended to be a test bed.)
: I see no other changes needed in this file, and few
implications
: that I'm going to cause major problems with this change. On to
: the next.
: Second changes needed, in file
: /usr/src/linux/include/asm-i368/shmparam.h:
: Now, here's the part upon which I am really stumped.
: change #define SHMMAX 0x2000000 to #define SHMMAX 0xFFFFFFFF
: (I'm pretty sure that decimal 4294967295 is hex FFFFFFFF,
though
: the latter is a lot easier to write correctly!)
: I looked up a few lines and read
: SHMMAX <= (PAGE_SIZE << SHMIDX_BITS
: Currently, PAGE_SIZE is set in
: /usr/src/linux/include/asm-i368/page.h
: to 1UL<<12 (0x1000).
: However, SHMIDX_BITS + SHMID_BITS <= 24 from a few lines
: above. And, from a few more lines above, SHMIDX_BITS is set
to
: 15 and SHMID_BITS is set to 7. So, either I can tweak the two
: BITS values or the PAGE_SIZE, right? (THIS IS NOT A RHETORICAL
: QUESTION. I WOULD LIKE YOUR INPUT!).
: However, to get SHMMAX to 2^32 with a page size of 2^12, I
would
: need SHMIDX_BITS set to 20, which would leave only 4 bits for
: SHMID_BITS, which woud lin turn put SHMMNI at 16, which is
too
: low for the value recommended in the oracle manual, 100 (I
wonder
: if that is really 100 or if it is supposed to be 0x100...).
: ANYway, It looks like I cannot do the whole job with
SHM_BITS,
: or even most of it.
: This seems to lead me to adjusting page size, from 2^12 to
2^15.
: To do this, I'll need to alter /usr/src/linux/mm/kmalloc.c in
: order not to break the PAGESIZE-dependent structs. Does this
make
: sense?
: Has anyone (even at Oracle...) done this level of analysis when
: installing Oracle8 on Linux?
: I saw that a few people have edited files, but few have
mentioned
: which files, and I have seen no details at all on the changes
: made. Does this resemble the reasoning that they took?
: Do I really have to change PAGE_SIZE to pull this off?
: Do the instructions need to be changed? I think that they could
: be a little more explicit, IMHO.
: If you have read this far, thanks very much! I look forward to
: your feedback.
null