updating informations of file systems

updating informations of file systems

[Pol]

Sometimes i happened to notice that the result of the 'du -s' command on a
ext3 partition  of my local disc does not yield the real value. 
My impression is that, some times, it may take hours, before the real space 
used by the partition being updated.
Is that possible?

Thank you

--Pol 

Re: updating informations of file systems

[Glynn Clements]

Pol wrote:

> Sometimes i happened to notice that the result of the 'du -s' command on a
> ext3 partition  of my local disc does not yield the real value. 
> My impression is that, some times, it may take hours, before the real space 
> used by the partition being updated.
> Is that possible?

No.

BTW, "du" reports the space used by a specific set of directories. If
you want to know the total amount of space free and used for a
partition, you need to use "df".

Apart from anything else, "du" won't report the space used by files
which have been deleted (unlinked) but still exist because a process
is using them.

-- 
Glynn Clements <glynn@gclements.plus.com>

Re: updating informations of file systems

[Pol]

Glynn Clements wrote:
> Apart from anything else, "du" won't report the space used by files
> which have been deleted (unlinked) but still exist because a process
> is using them.
>

Sorry, i meant 'df'. 
Is it possible 'df' does not report the current amount of space used by
partitions?

thank you
--Pol 

Re: updating informations of file systems

[Glynn Clements]

Pol wrote:

> > Apart from anything else, "du" won't report the space used by files
> > which have been deleted (unlinked) but still exist because a process
> > is using them.
> 
> Sorry, i meant 'df'. 
> Is it possible 'df' does not report the current amount of space used by
> partitions?

No. Any allocation or deallocation of blocks will be immediately
reflected in the output from "df" (for local filesystems, at least;
there may be issues with networked filesystems).

-- 
Glynn Clements <glynn@gclements.plus.com>

Re: updating informations of file systems

[Chamith Kumarage]

On Tue, 2009-02-10 at 09:03 +0000, Glynn Clements wrote:
> Pol wrote:
> 
> > > Apart from anything else, "du" won't report the space used by files
> > > which have been deleted (unlinked) but still exist because a process
> > > is using them.
> > 
> > Sorry, i meant 'df'. 
> > Is it possible 'df' does not report the current amount of space used by
> > partitions?

General "df" output will describe the following fields..

Filesystem |1K-blocks | Used | Available | Use% | Mounted on

As Glynn explained, there are issues in "df" with networked filesystems
like NFS. There it will print blanks for attributes that the server
doesn't support.

~Chamith

> 
> No. Any allocation or deallocation of blocks will be immediately
> reflected in the output from "df" (for local filesystems, at least;
> there may be issues with networked filesystems).
> 
-- 
*** Microsoft isn't evil, they just make really crappy operating systems ***

Re: updating informations of file systems

[Pol]

Glynn Clements wrote:
> Pol wrote:

>> Sorry, i meant 'df'.
>> Is it possible 'df' does not report the current amount of space used by
>> partitions?
> 
> No. Any allocation or deallocation of blocks will be immediately
> reflected in the output from "df" (for local filesystems, at least;
> there may be issues with networked filesystems).
> 

Problem must be in the temp files and directories managed by ktorrent.
According to ktorrent, 2 GB of a 4 GB directory have been downloaded in the
last 24 hours, yet 'df' shows no sensible change of the available space in
that partition.
Remarkably, 'du -s' returns 4GB for that directory, although my guess is
that size is only 2GB actually. 
How to double check size of that directory and files therein?

Thank you
--Pol

     

Re: updating informations of file systems

[Glynn Clements]

Pol wrote:

> >> Sorry, i meant 'df'.
> >> Is it possible 'df' does not report the current amount of space used by
> >> partitions?
> > 
> > No. Any allocation or deallocation of blocks will be immediately
> > reflected in the output from "df" (for local filesystems, at least;
> > there may be issues with networked filesystems).
> > 
> 
> Problem must be in the temp files and directories managed by ktorrent.
> According to ktorrent, 2 GB of a 4 GB directory have been downloaded in the
> last 24 hours, yet 'df' shows no sensible change of the available space in
> that partition.
> Remarkably, 'du -s' returns 4GB for that directory, although my guess is
> that size is only 2GB actually. 

It's not uncommon for BitTorrent clients to start by creating all of
the files with the correct sizes, then insert the data into the files
as it's received.

If ktorrent does this, then it will use the full 4GB from the start,
so you wouldn't see any change in disk usage while it is running.

> How to double check size of that directory and files therein?

"du" will count the disk space actually used by each file, including
indirect blocks and slack space, and not counting holes (blocks of
zeros which aren't stored on disk). Files with multiple links are only
counted once.

Note that the result of "du -s ..." for the root of a filesystem won't
match the result of "df", as "du" doesn't count blocks which aren't
associated with a specific file (e.g. superblocks, inode table, free
space bitmap), or which belongs to a file with no links.

-- 
Glynn Clements <glynn@gclements.plus.com>