2006/6/3, EKC <[EMAIL PROTECTED]>:
Hello,
Given a running vserver <parent_vserver>, I would like to create
multiple <child_vserver> instances of the running parent vserver as
quickly as possible.
Currently, I am doing this by:
==Creating the parent vserver:==
1) Building the <parent_vserver> from scratch using: 'vserver
parent_vserver debootstrap...'
2) Running 'vserver parent_vserver hashify'
==Stopping The Parent vserver==
1) vserver parent_vserver stop
==Creating an instance of the parent:==
1) vserver child_vserver build -m skeleton --interface eth0:192.168.1.2
2) rm -rf /vservers/child_vserver/*
3) vcopy --manually -v /vservers/child_vserver ' ' /vservers/parent_vserver ' '
4) vserver child_vserver hashify
5) vserver child_vserver start
==Restarting the parent_vserver:==
1) vserver parent_vserver start
Question: This procedure is _very_ slow to execute (on the order of
minutes); is there a faster way to do this? Also, can a copy and
hashify a running vserver without stopping it first?
Specifically: I want to use the COW feature of linux-vserver to create
copies of vservers. Ideally, I would create a copy by creating a hard
link to the parent_vserver and passing the hard link to 'vserver
<hard_link_to_parent_vserver> start'. How would I go about doing this?
This would allow me to clone vservers almost instantly. COW would take
care of copying files from the hashified parent vserver to the child
vserver when the child vserver reads/writes/renames/chmods/chowns a
file.
I'm really hoping there's a way to do this.
Thanks for vserver! And thanks in advance for your help.
EKC
As a quick guess, you might cp -la the unified files and cp -a (or
rsync or whatever) the guest-specific data. This might or might not
work (I'm not sure how will the CoW mechanism work with a plain cp -l)
but it might be a starting point for a more elegant solution.
Hardlinking the files in the first place instead of cp + vhashify
(which AFAIK computes the sha1sum and replaces the original file with
a hardlink) should be significantly faster. Still, it's just a quick
idea based mostly on speculation. If you try this, please provide some
feedback (if it helps anything etc.)
Best regards,
Grzegorz Nosek
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