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Re: [Fwd: UNIX Performance Issues]

From: Rahul Dandekar <rvd_oracle_at_hotmail.com>
Date: Tue, 19 Feb 2002 07:48:33 -0800
Message-ID: <F001.004130D1.20020219074833@fatcity.com> 





MessageJames,



Getting interesting, isn't it? I have added my response...






  Rahul,



  Here's what I would do. 


    
  
  1.   I would use "mpstat" for the processor statistics. This breaks the usage up by processor in SMP configurations. This can be useful to see the relative loading of each CPU, in particular the breakdown of kernel and user time.
  
  2.   Memory: Concentrate on Page Outs and Free Memory more than anything else. That will give you plenty of clues about memory starvation, and the relevence of your VM tuning.
  
  3.   I/O: User "sar -d". It's a bit annoying on a system with a lot of disks, because it returns a row for every device, even if no I/O occurred in the sample period. However, it makes it easier to parse. ;-) Notably, keep an eye on the Service Times (avserv?), Wait times (avwait), and the queue depth. The utilisation is a function of these (queuing theory), but you can store that too as a shortcut. You can give sar any sample period, so your 5 minute averages are no problem.
How can I get the current I/O load on the system? I don't know exactly what metric I am looking for.
But I want to establish some baseline metric for each machine and then hunt for spikes from the
gathered data. The metric can be "I/O load on system bus in Mb/sec" (like the netstat info packets
input and output). I don't want individual disk statistics. I just want a overall number, which I
can snapshot.
  
  4.   Network: "netstat 5" will report a row for every 5 seconds (for example), showing how many packets went in and out of each interface. Your question below is easily answered - you have two columns in your output; the first is for the named interface (hme0), the 100baseT network card. The second is a total of all cards - looks like you only have one. This total can also include the loopback interface (lo0), so look out for that.
If I have only one card then why the total and hme0 data are different (by about 10%)?
  Good luck, you're doing the right thing. I've been working on some software to do just this for a couple of years. I'd love to hear how it goes!
+Rahul
  Regards






  James


  --


  James Morle


  Scale Abilities, Ltd


  http://www.scaleabilities.co.uk


  Author of "Scaling Oracle8i - Building Highly Scalable OLTP System Architectures" 
    -----Original Message-----


    From: root_at_fatcity.com [mailto:root_at_fatcity.com] On Behalf Of Rahul Dandekar
    Sent: 19 February 2002 12:59


    To: Multiple recipients of list ORACLE-L
    Subject: Re: [Fwd: UNIX Performance Issues]




    James,



    Interleaved, please find my reply....



    +Rahul





      Rahul,



      Did you get a response on this? I'm not sure I fully understand the actual question - are you looking for specific commands you need to run to get the information, 
    [Rahul] Yes. I would like to know which flags of the commonly used commands give good information.
    For general System stats, I use "sar -u" (same as default), for Memory / Virtual Memory I use "vmstat"
    and look for "r   b   w   swap   free   pi   po   us   sy   id" columns.
    I am looking for general monitoring. And once we have this general information giving a overall picture,
    we could know if there is a problem and we could investigate further.
    I am specifically looking for IO and Network statistics.
    Is there any command which would give me approx IO of the system, say in last 5 minutes or
    current?


    How to get network statistics? I was littlebit confused with netstat. There are two main categories
    in my output : hme0 and Total. What does that mean?


        input   hme0      output           input  (Total)    output
    packets errs  packets errs  colls  packets errs  packets errs  colls

    5757291 0     2447690 0     0      6071152 0     2761551 0     0
    45      0     1       0     0      45      0     1       0     0
    24      0     2       0     0      24      0     2       0     0





    What I plan to do is to take snapshot of all these statistics at a certain frequency and put it
    in database. Later on I could generate reports based on this.
    Currently, I have a lot of "Camera"s like this taking snapshots of my system.
    Others involve Oracle stuff like DB Size Growth, Performance Ratios, UNIX File System
    usage, Replication Statistics, Growth of DB objects, a lot of monitors for application
    info (e.g. total # of clients, # of invoices generated per day).
    I generate trends based on this archival data for capacity planning and proactively
    anticipating chronic problems.

      or advice on how to interpret it? Don't forget that you will really need to correlate many of these 
      statistics to the Oracle pathology at the same time. 


    You said it! I want co-relation of Application Load, UNIX System Load and Database Statistics.
    And not just when the problem arises. So, that's what I am trying to develop.


      This then causes a problem because your sample points will at the very least experience clock drift and become harder to compare over time. There are ways to solve it, though. 
      Anyway, if you could elaborate a little, I can try to assist!
      Regards

      James
      --
      James Morle
      Scale Abilities, Ltd
      http://www.scaleabilities.co.uk
      Author of "Scaling Oracle8i - Building Highly Scalable OLTP System Architectures" 

        -----Original Message-----
        From: Mogens Nørgaard [mailto:mln_at_miracleas.dk] 
        Sent: 18 February 2002 22:11
        To: James Morle
        Subject: [Fwd: UNIX Performance Issues]


        Hi James,

        I've got no idea whether this is of interest or not to you, but you probably know a bit about this topic.

        Mogens

        -------- Original Message -------- Subject:  UNIX Performance Issues 
              Date:  Thu, 14 Feb 2002 07:43:26 -0800 
              From:  "Rahul Dandekar" <rvd_oracle_at_hotmail.com> 
              Reply-To:  ORACLE-L_at_fatcity.com 
              Organization:  Fat City Network Services, San Diego, California 
              To:  Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com> 







DBAs,



This might be littlebit (or completely!) UNIX related... But I am told
to do the performance analysis of some 10-15 machines and generate
some statistical data to find out bottlenecks and identify areas of
tuning...



Operating System : Solaris 2.6



I have been using sar, iostat, top...


I actually plan to script these things and run these scripts at certain
intervals and put the data in database (Oracle 8i) and then do the
crunching...


Inputs are appreciated...



    
  
  1.   I/O
   What is current I/O status. Is there a lot of I/O going on?

  
  2.   Paging
   Is there lot of swapping / paging happening?
   Which processes are getting swapped in/out continuously?
   Are the I/O waits due to swapping / paging or regular stuff
   like DB waiting to read from DB files?

  
  3.   CPU

   What is the CPU utulization? Which processes are using lot of CPU?

  
  4.   Memory
   What is the current picture of Real and Virtual Memory?
   What processes are using how much memory? Which processes
   are i
n real memory and which are in virtual memory?
   Which processes are swapped in and out from/to real/virtual memory
   and how many times?

  
  5.   Network
   What is the percentage utilization of network pipe?
   What is the capacity (bandwidth) of the network device?
   What percentage of that bandwidth is getting used?
   Is the system waiting for data from outside network I/O?
   In short, is there any bandwidth problem with network device
   or network traffic.






Thanks,


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Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Rahul Dandekar
  INET: rvd_oracle_at_hotmail.com

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-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Rahul Dandekar
  INET: rvd_oracle_at_hotmail.com

Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051
San Diego, California        -- Public Internet access / Mailing Lists
--------------------------------------------------------------------
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Received on Tue Feb 19 2002 - 09:48:33 CST












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