size from df -kh vs size from fdisk -lf

[Aldo Foot]

On Tue, Apr 21, 2009 at 2:52 PM, jackson byers <byersjab at gmail.com> wrote:
>
>> sda1 size = 190M
>>
>> how possible?
>> advice, help on further  diagnosing this?
>> Jack
>
> After using fdisk or parted, one must do "partprobe" at the CLI to record
> the changes. Both the OS and the Kernel need to know the changes.
> Since your boot partition is involved, you may need a LiveCD for this.
> Do "man partprobe" for more info.
>
> HTH,
> ~af
>
> -----------------------
>
> but "I" didnt "consciously" use fdisk or parted on sda.
> If it happened bc of my clutzy use of the liveinstall cd
> then maybe I did, without knowing it.

I don't think it was something you did. The install was just not
smart enough to be one with the "force"  :-)

> Actually my present boot partition is sdb6,  /boot a dir inside,
> so present /boot not involved with my installcd mistakes on sda1.
> I have systemrescue cd so i probably can use that.
>
> I have never heard of partprobe
> is it really necessary if reboot after using fdisk,parted,gparted
> if reboot after?

Before partprobe came into the picture you'd have to reboot the
system to validate filesystem modifications; partprobe takes care of
this on the fly.

> I am unclear re man page
>        partprobe - inform the OS of partition table changes
>
>        partprobe [-d] [-s] [devices...]
>
>      partprobe is a program that informs the operating system kernel of
> parti-
>      tion table changes, by requesting that the operating system  re-read
> the
>      partition table.
>
> OPTIONS
>        -d     Don’t update the kernel.
>        -s     Show a summary of devices and their partitions.
>
> what exactly does   -d  do?

Just that. The changes are not noted by the kernel.

> -s   do nothing except show summary ?
>
> are you saying  to  run it
> as  partprobe /dev/sda1
> or  partprobe /dev/sda  ?

At the CLI just type the command by itself and press enter. It will detect
changes to any attached HDD.
     $ sudo parprobe

> will this operation shrink the size seen by fdisk to what is seen by df?
> or what?
> will it affect
> sda2  swap
> sda3 another linux partition
> ?

Parprobe does not do resizing nor does it affect partitions; it simply rereads
the partition table without rebooting and reports the changes to the kernel.

> parted  shows same thing, but additional "incompatible feature"
> root at bootp ~]# parted /dev/sda
> Using /dev/sda
> (parted) unit mb print
> Disk geometry for /dev/sda: 0MB - 36704MB
> Disk label type: msdos
> Number  Start   End     Size    Type      File system  Flags
> 1       0MB     22011MB 22011MB primary   ext3         boot
> 2       22011MB 26017MB 4006MB  primary   linux-swap
> 3       26017MB 36701MB 10685MB primary   ext3
> (parted) check 1
> Warning: Partition 1 is 22011MB, but the file system is 206MB.
> Ignore/Cancel? ignore
> Error: File system has an incompatible feature enabled.
>
> does this last  tell us anything useful?
> perhaps better to just reformat sda1?

That's informative. I would do one of two things: (a) reformat the partition
and create a new filesystem, or (b) use GParted to grow the filesystem to
the full extent of the partition.
Note that a partition can be 200GB, but there could be a small filesystem that
does not occupy the entire partition... such is your case.

Look at this as a great learning experience to understand partitions.
Don't be afraid to experiment. Only save your data in an external source
for safety.

> thanks  for response
> Jack


Glad to help. Only help someone else when your time comes.
~af