Re: [vserver] Copy-on-write Hard Links, Shared Libraries, Prelink and Memory

On Thu, Jun 10, 2010 at 02:53:24AM +0200, Herbert Poetzl wrote:

> > beryllium:~# df -k
> > Filesystem 1K-blocks Used Available Use% Mounted on
> > /dev/sda1 73742752 42989868 27006932 62% /
>
> this shows me that you do not favor a good design, as
> putting _everything_ on one partition (including the
> guests, which might need/want filesystem tagging sooner
> or later) ...

It's an experimental setup. It uses a 80 GByte SSD for / and
vservers, and mirrors the 80 GByte to a 1 TByte WD RE3 drive
as I've empirically learned that SSDs are not long for this
world. The rest of the 1 TByte drive is for /home for the
vservers.

I would have used a dedicated root if I had a 160 GByte SSD.
 
> > Is there a way to verify the symlinks are actually there?
>
> there are no symlinks, unification uses hard links ...

Thank you. I should really try reading documentation sometime.
 
> > I don't see them in the filesystem explicitly.
>
> hard links are indistinguishable from the original file
> even more, there is no 'original' as each directory
> entry pointing to an inode is a file, regardless if it
> is sharing the content (data) with another entry
>
> > Does the kernel hide it?
>
> nope, you can see them via the link count ....

-- 
Eugen* Leitl leitl http://leitl.org
______________________________________________________________
ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org
8B29F6BE: 099D 78BA 2FD3 B014 B08A  7779 75B0 2443 8B29 F6BE