Re: How does fragmentation work?

From: Eve Zeng (eve@ASIRIUS.COM)
Date: Thu Jul 25 2002 - 05:12:14 EDT


oh, I see. Thanks Simon. Yup, when I set the same nbpi to both filesystems,
I got the result. Thanks again!

Cordially
Eve Zeng
IT Consultant
Asirius Pte Ltd
Tel:65-62279-002
Fax:65-62277-528
E-mail:eve@asirius.com
URL: www.asirius.com
  -----Original Message-----
  From: IBM AIX Discussion List [mailto:aix-l@Princeton.EDU]On Behalf Of
Green, Simon
  Sent: Thursday, July 25, 2002 4:46 PM
  To: aix-l@Princeton.EDU
  Subject: Re: How does fragmentation work?

  The nbpi size affects this, as inodes take up space and a small nbpi means
there are more of them. Try it again, specifying the same nbpi for both
filesystems.

  Simon Green
  Philip Morris ITSC Europe

  AIX-L Archive at http://marc.theaimsgroup.com/?l=aix-l&r=1&w=2
  AIX FAQ at http://www.faqs.org/faqs/aix-faq/

  N.B. Unsolicited email from vendors will seldom be appreciated.

    -----Original Message-----
    From: Eve Zeng [mailto:eve@ASIRIUS.COM]
    Sent: 25 July 2002 04:03
    To: aix-l@Princeton.EDU
    Subject: How does fragmentation work?

    Hi,

    Can anyone of you explain this: I have created 2 filesystems as shown
below, /tmp/frag4096 created with fragmentation size 4096 and nbpi 4096,
/tmp/frag512 created with fragmentation size 512 and nbpi 512, and I stored
50 512-byte files in each filesystem, theoretically /tmp/frag512 should save
more space when storing small files, but it doesn't seem to be the case,
why?
    Filesystem 512-blocks Free %Used Iused
%Iused Mounted on

    /dev/lv01 32768 31256 5% 67
2% /tmp/frag4096

    /dev/lv02 32768 24416 26% 67
1% /tmp/frag512

    Any prompt reply will be greatly appreciated!



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