Thread: plz help
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Old 01-05-2008, 05:29 AM
Andreas Schulze
 
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Default Re: plz help

> Andreas Schulze wrote:
> > "Ashutosh" <hiashutosh@gmail.com> schrieb im Newsbeitrag
> > news:1104904203.359535.324540@z14g2000cwz.googlegr oups.com...
> > > HI Group!!
> > > Im rather new to AIX...
> > > Plz let me know if there is any basic difference between mkfs &

> crfs...
> > > Are they two different commands to do the same thing or is there

> any
> > > criteria to decide when to use any of these commands...
> > > Thanks in advance...
> > > Regards,
> > > Ashutosh
> > >

> > crfs needs lv being created already. crfs is better whenever you

> need/want
> > to control where fs shall be placed. man mksfs, man crfs, man mklv.

>

"Ashutosh" <hiashutosh@gmail.com> schrieb im Newsbeitrag
news:1104920954.078768.300270@c13g2000cwb.googlegr oups.com...
> HI Andreas!!
> Thanks a lot for your response..
> But according to man crfs,
> 1.)A new logical volume is created for the file system unless the name
> of an existing logical volume is specified using the -d.
> 2.) Mount point can be controlled both in mkfs & crfs....
> Plz let me know your views on this...
> Thanks,
> Ashutosh
>


Hallo Ashutosh,

Your focus should not be on the mountpoint because this is of almost no
interest in this comparison. crfs will create an lv if none exists but mkfs
(opposed to crfs) cannot use an lv if it exists. The difference will play a
role when you want to use a dedicatet area on your physical disk for your
filesystem.
E.g. you have an fs that is rarely used and thus shall occupy pp in inner
edge area only ( because all the "high speed" areas center and middle are
either being used or reserved). Then you would create the lv first because
only then you can tell LVM which hdisk area to use. (You could even use a
map file to specify distinct pp). Next you would use crfs to create your fs
there. This cannot be achieved with mkfs.

Having said that I shall like to add that the same is true for extending an
fs. If you use chfs -asize=... the lvm will take just any free pp it can
find (within certain limits). If you want to be in charge of which pp to use
(sure you want to because you are admin) you'd use extendlv first and extend
the fs accordingly afterwards.

HTH,
Andreas

A: Because doing so makes the conversation harder to read.
Q: Why should I not top-post?


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