Re: Compressed disk.. -- MIDRANGE-L

At 08:16 AM 8/6/99 -0500, you wrote:

Making the option to overflow, as opposed to freezing everything that 
touches that ASP (including WRKSYSSTS and WRKDSKSTS), posting an SRC code 
and not posting a QSYSOPR message.

Al

>Al,
>
>By getting them to change it do you mean you got them to fix the % used?
>Or, just that they added the option to overflow to another asp?
>
>
>
>
>
>barsa2@ibm.net on 08/05/99 05:47:07 PM
>Please respond to MIDRANGE-L@midrange.com@Internet
>To:     MIDRANGE-L@midrange.com@Internet
>cc:
>Fax to:
>Subject:        Re: Compressed disk..
>
>At 10:10 AM 8/5/99 -0700, you wrote:
>
>Hi,
>
>You're right, and this is how it works on V4R3 default as shipped.
>
>When I discovered this, I bitched so loud that I actually got them to
>change it.  (In truth, I probably wasn't the only person bitching, but I
>might have been the loudest!)  In V4R4 the default is to overflow the User
>ASP.  You can then change it work like V4R3 with the new CHGASPA command.
>
>I think that there's a PTF available for V4R3 to allow you to change the
>attribute.
>
>Al
>
>
> >Hello everyone...
> >
> >I've "discovered" something very interesting today. If you are using
> >"compressed disk" on your AS/400 you probably want to read on...
> >
> >I have an S20 server. ASP2 in this server contains 10  8GB disks which have
> >been configured as compressed disk.
> >
> >Yesterday I was experiencing problems with this S20 server. All disk I/O to
> >ASP2 was suspended and there was an SRC code on the control panel that
> >indicated all disk in ASP2 was full.
> >
> >What is interesting about this is that the WRKDSKSTS command indicated that
> >the disk was only 58-65% full....
> >
> >How can this be?
> >
> >After a long conversation with IBM SupportLine I found out that the disk
> >measurement algorithm in OS/400 makes some assumptions.
> >
> >One of these assumptions is that if you configure a disk as a "compressed
> >disk" you will get at least a 2 to 1 compression on any data written to that
> >disk. Therefore it assumes that a physical 8GB drive is now a virtual 16GB
> >drive.
> >
> >This was probably more of a marketing decision that a technical one. I can
> >hear the IBM marketing team now... "Lets show the disk as being twice as
> >big!"  "The customer will think that they got a 16GB drive for the cost of
> >an 8GB drive!!!"
> >
> >Well, no matter what the operating system reports, the disk is still an 8GB
> >disk.
> >
> >Our problem was that we were sending lots of data to this ASP via NFS, that
> >was already compressed. The disk IOP could not compress it any further,
> >therefore the assumption that it could be compressed at least 2 to 1 didn't
> >hold. We filled up our 10-8GB disk subsystem with this compressed data while
> >the WRKDSKSTS command only reported that we were around 60% full...
> >
> >IBM is now aware of this problem. I'm waiting to hear from them if they are
> >going to do something about it.
> >
> >In the mean time I have quite a challenge in how I'm going to manage my disk
> >space.  Especially since I never really know how much disk is actually being
> >used.
> >
> >
> >Kenneth
> >
> >--
> >********************************
> >Kenneth E. Graap
> >IBM Certified Specialist
> >AS/400  Professional
> >System  Administrator
> >NW Natural - Information Services
> >System Services
> >Phone: 503 226 4211 X5537
> >FAX:   603 849 0591
> >keg@nwnatural.com
> >********************************
> >
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>
>Al Barsa, Jr. - Account for Midrange-L
>Barsa Consulting, LLC.
>400 > 390
>
>Phone:          914-251-1234
>Fax:            914-251-9406
>http://www.barsaconsulting.com
>http://www.taatool.com
>
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+--------------------------------------------------+
| Please do not send private mail to this address. |
| Private mail should go to barsa@ibm.net.         |
+--------------------------------------------------+

Al Barsa, Jr. - Account for Midrange-L
Barsa Consulting, LLC.  
400 > 390

Phone:          914-251-1234
Fax:            914-251-9406
http://www.barsaconsulting.com
http://www.taatool.com

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