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System slow when ......

Occasional Contributor

System slow when ......

Hi all,
I'm using oracle on hp-ux 11.0.
System becomes very while creating tablespace.
Even, bdf, cd command r not working during tablespace creation.
Is there any workaroung to solve this problem?


Hello unix
T. M. Louah
Esteemed Contributor

Re: System slow when ...... of the first test I `d run is to sort all the proceses by memory size:
# UNIX95= ps -eo vsz,ruser,args | sort -rn | more
If any of the processes are pushing more than 50 megs, run SAM & change maxdsiz to double or even higher (requires a reboot).

# export UNIX95=""

g`d luck
Little learning is dangerous!
Thierry Poels_1
Honored Contributor

Re: System slow when ......


ain't this a little bit normal? Tablespace creation creates a (large) datafile on the server; and is extremely I/O consuming.
Also the autoexend option of oracle datafiles is a performance killer.
Maybe you could schedule tablespace creations and extends at off-peak hours.

All unix flavours are exactly the same . . . . . . . . . . for end users anyway.
Bill Hassell
Honored Contributor

Re: System slow when ......

First, is Oracle actually supported on 11.0?

Also, it is NOT a good idea to set: export UNIX95="" as this environment variable will change the behavior of many other programs and libraries. Use it as shown on the same line as ps and it will not stay set.

As mentioned, table space is a very intense, serial I/O task, so random I/O like bdf or cd or even a login will be delayed. This is caused by the kernel's preference to process all serial requests first, but this sometimes delays other random commands (that look at disk files) for minutes.

If you plan on creating tablespaces all the time (?) or doing other serial-intensive disk reads or writes (such as a backup) during working hours, change the parameter disksort_seconds to 2 or 4 or 8 seconds. Check out this link:,,0xcb327b8d1de3d5118ff40090279cd0f9,00.html

Bill Hassell, sysadmin
harry d brown jr
Honored Contributor

Re: System slow when ......


As you can see, oracle is a pig. Have your dba's thought about raw device IO?

live free or die
Live Free or Die
Dennis J Robinson
Frequent Advisor

Re: System slow when ......

We need the following information:

System information:

# of CPU's:
I/O cards:

Need to know where the Oracle datafiles live (local disk, EMC, etc).

Need to know how many SCSI and Fibre controllers you have.

Need to know how large dbc_max_pct is.

Creation of tablespaces should not slow an entire system down.

Now if we are talking about an HP workstation with one SCSI controller and tablespace is created on same disk as the system, then yes performance should suffer.

There are still some tuning that can be done to help alleviate this type of problem.
You know the drill