DSA 7.13: VP question

DSA 7.13: VP question

Post by Rob Pro » Sun, 31 Dec 1899 09:00:00



Hi,

1. A client of us is upgrading his system with some extra disks. The
problem is that 50% of the disks (2 out of 4) are only used to hold
historical data that is almost not queried, and certainly not updated.
How many AIO VP's should I define, 1 for every (physical) disk or only 1
for every (physical) disk that does not contain historical data.

2. An other problem we have is that the system sometimes seems to lock
itself up. The system is for example 40% idle and if another proces is
started it changes to 0% idle. The server is an HP9000-K210 1 proc. and
Informix DSA 7.13. This machine is the application and database server.
My guess is that with the multi-threading architecture the defined CPU
VP (only 1 defined like mentioned in the manuals)gets less time to do
more work if a lot of user-programs are running. Is it wise to define
more than 1 CPU VP. The workload consists of a mix of interactive and
batch programs.

Thanks in advance,

        Rob Prop

--
 ===============================================================
   Rob Prop                       Tel. : +31-164-255300        
   Consultant                     Fax. : +31-164-246162        


   The Netherlands                Web  : http://www.informa.nl  
 ===============================================================

 
 
 

DSA 7.13: VP question

Post by Stefan Weidenede » Sun, 31 Dec 1899 09:00:00



> Hi,

> 1. A client of us is upgrading his system with some extra disks. The
> problem is that 50% of the disks (2 out of 4) are only used to hold
> historical data that is almost not queried, and certainly not updated.
> How many AIO VP's should I define, 1 for every (physical) disk or only 1

If your machine supports KAIO I would suggest to use KAIO ( HP-UX 10.x
supports KAIO I guess ) and set the number of CLEANER threads to 2 and
NUMAIOVPS to 1.

Generally it must be better to have less AIO-vp's than too many.

Quote:> for every (physical) disk that does not contain historical data.

> 2. An other problem we have is that the system sometimes seems to lock
> itself up. The system is for example 40% idle and if another proces is
> started it changes to 0% idle.

If the system changes to 0% idle when you start an additional ( not an
oninit ) process, then I think either the oparating system has to
manage too many processes or the process you started needs a lot of
CPU-time.

Quote:> The server is an HP9000-K210 1 proc. and
> Informix DSA 7.13. This machine is the application and database server.
> My guess is that with the multi-threading architecture the defined CPU
> VP (only 1 defined like mentioned in the manuals)gets less time to do
> more work if a lot of user-programs are running. Is it wise to define
> more than 1 CPU VP. The workload consists of a mix of interactive and
> batch programs.

Because you do not have more CPU-time ( idle 0% ) it will not make
sense to start an additional CPU-vp.
To disable Priority Aging might be a solution, but this parameter
is a critical parameter on a few platforms.
If you're sure to have a lack of CPU-time I think it's a good idea
to add two or three physical CPUs.

> Thanks in advance,

>         Rob Prop

> --
>  ===============================================================
>    Rob Prop                       Tel. : +31-164-255300
>    Consultant                     Fax. : +31-164-246162


>    The Netherlands                Web  : http://www.informa.nl
>  ===============================================================

Bye

Stefan

 
 
 

DSA 7.13: VP question

Post by David William » Sun, 31 Dec 1899 09:00:00





>> Hi,

>> 1. A client of us is upgrading his system with some extra disks. The
>> problem is that 50% of the disks (2 out of 4) are only used to hold
>> historical data that is almost not queried, and certainly not updated.
>> How many AIO VP's should I define, 1 for every (physical) disk or only 1

>If your machine supports KAIO I would suggest to use KAIO ( HP-UX 10.x
>supports KAIO I guess ) and set the number of CLEANER threads to 2 and
>NUMAIOVPS to 1.

>Generally it must be better to have less AIO-vp's than too many.

>> for every (physical) disk that does not contain historical data.

>> 2. An other problem we have is that the system sometimes seems to lock
>> itself up. The system is for example 40% idle and if another proces is
>> started it changes to 0% idle.

>If the system changes to 0% idle when you start an additional ( not an
>oninit ) process, then I think either the oparating system has to
>manage too many processes or the process you started needs a lot of
>CPU-time.

>> The server is an HP9000-K210 1 proc. and
>> Informix DSA 7.13. This machine is the application and database server.
>> My guess is that with the multi-threading architecture the defined CPU
>> VP (only 1 defined like mentioned in the manuals)gets less time to do
>> more work if a lot of user-programs are running. Is it wise to define

  Yes.

Quote:>> more than 1 CPU VP. The workload consists of a mix of interactive and
>> batch programs.

>Because you do not have more CPU-time ( idle 0% ) it will not make
>sense to start an additional CPU-vp.

 Agreed. YOu have set SINGLE_CPU_VP = 1 and MULTIPROCESSOR=N havn't you?

 Also make sure you have enough semaphores available in the kernel.
 I have seen that on Phyramid it will go to 0% idle if online can not
 get a semaphore it needs.

- Show quoted text -

>To disable Priority Aging might be a solution, but this parameter
>is a critical parameter on a few platforms.
>If you're sure to have a lack of CPU-time I think it's a good idea
>to add two or three physical CPUs.

>> Thanks in advance,

>>         Rob Prop

>> --
>>  ===============================================================
>>    Rob Prop                       Tel. : +31-164-255300
>>    Consultant                     Fax. : +31-164-246162


>>    The Netherlands                Web  : http://www.informa.nl
>>  ===============================================================

>Bye

>Stefan

--
David Williams
 
 
 

1. Questions on INFORMIX 7.13 and CPU VPs

     Hi everybody,
     Some more questions for everybody. Feel free to answer
     . I have a lot of questions on CPU VPs and performance. Here goes:

     some background info:
     OS -AIX 4.1
     Informix : 7.13 UC1
     Number of CPUs - 8

     1. Is it true that we can configure only one NETTYPE connection on the
     CPU VP ? Currently, both my NETTYPE connections ( SOC and SHM ) are
     configured on CPU VPs. If my assumption is true, does INFORMIX
     automatically force the second NETTYPE connection to a NET vp ?

     2. I expect about 400 connections through shared memory and 200
     through SOC. Which of the connections should be configured through CPU
     VP ? The ODS Performance guide suggests that if # of connections >
     350, then performance would be improved by assigning a NET VP to it.
     Any comments ??

     3. An onstat -g sch  shows some of my CPU VPs to be a whole lot more
     busy than the others. What determines the usage of a CPU VP ?

     4. Okay, a question not related to CPU VPs. At the end of an onstat -u
     output, we see the following line:
     # active,       # total,        # concurrent.
     If we actually count the total # of sessions, it matches with the
     "# active". Where does the "#total " and "# concurrent" come from ?

     5. Okay, I am going to cheat again and ask another non-CPU VP question
     onstat -g ioq , shows me a Queue named "kio". I do not think that
     this is related to the KAIO. Matter of fact, the total number of these
     queues seems to equal the NUMCPUVPS. Comments ??

     No more for now.

     Thanks in advance.

     Sujata

2. what index to use of foreign key columns

3. Locking DSA 7.13

4. Print Report titles even if no records returned

5. Question about update of 7.13 to 7.23

6. OpenROAD 3.0 -> 3.5

7. Informx-SE (7.13) Basic DBA question

8. DBMS_JOB Interval

9. ODBC for Oracle 7.13

10. Problem w/ODBC connecting to Oracle server 7.13

11. Drop db spaces in 7.13

12. ESQL/C under 7.13

13. 7.12 or 7.13