Les Mikesell (lesmik...@gmail.com)

I'm confused.  Aren't you the same person who just put together some 
stuff that doesn't work well - or bought from a supplier that wasn't
picky about parts?

To someone who doesn't already have a windows license?

I'm not sure what you mean.  The way I use it, there is the 'virtual 
machine' and the image.  The image is transportable to any of the 
virtual machine hosts and with only the usual amount of pain to move a
working system to different hardware, to a physical host.  That's the 
least amount of lock-in I can imagine.  I do wish Centos had better 
hardware-migration tools, though.  

> Also, the conversation was specific about their hypervisor based
> products ESXi being the main one in question here.
>
OK, but you just said VMware...  I don't use any of the magic stuff that 
a physical machine can't do.  And using the server product I can run 
disk intensive things like databases and NFS home directories on the
physical host, something that seems to not be recommended under Xen.  
Virtualbox looks like a reasonable option these days too but I haven't
had a chance to try it out.

Karanbir Singh wrote:
>
> Anyway, I think the point is made, Vmware is by far the most locked in
> product out there, offers medium to low performance compared to other
> similar products, however has a lower user ability threshold to get into.

Do you mean some specific version of VMware or what as being locked
in?   I move images around among Linux/Windows/Mac hosts with the free 
server on Linux/Windows and Fusion on the Mac.

Microsoft has updated PPTP since the only paper I know about was
written.  Does anyone know if there are still problems with it or if the 
linux version is updated to match?

But, openvpn is easier to use if you control the clients.

You won't like that when you run into an rpm with a lot of dependencies.
  Just 'yum install yum-downloadonly', then
'yum --downloadonly packagename'.

Sean Carolan wrote:
> Is there an easy way to configure sendmail to only send mail to
> addresses in one particular domain?

If it is 'your' domain, configure the sender(s) to use the intended
receiving server as the SMART_HOST but don't give it RELAY permissions
in the receiving access file.   That way it can attempt to send to other 
addresses but only ones local to the receiving machine will be accepted.

What I've always wanted is a tool that would manage a group of machine
configurations as branches in subversion so the tool itself wouldn't
need any diffing capability and could be wrapped by viewvc for web
browsing, mesh nicely with router and other text base config management,
etc.   By 'configurations', on RPM based machines, I'd want the package 
list exported in a form that yum or kickstart could use to re-create the
set (and I suppose to get this right you also have to build a local
repository containing all of them because rpm/yum  are too dumb to know 
where they came from, given multiple repositories), and copies of all
the files in /etc/ and other optional places that are not exactly as
installed from an RPM.

Is such a thing feasible, and if you can get that far, can it become a
'configuration factory' where you'd copy the starting config close to
what you want to a new branch, edit a few files for the needed changes
to produce a new machine, commit them, and then have a tool build that
machine or a disk image of it?   What I'm after is something that will 
let me make on-the-fly changes to any running machine, but pull those
changes back to a central management tool in a way that makes it easy to
see differences across time or between similar machines, and to use the
current setup of any machine as the starting point for a new one.

Most of the tools I've seen so far involve their own abstractions to
describe configurations and require them to be made at the central
management tool.  That's not what I want.  I want to do configurations 
using the native setup on one or more machines whether or not the
management tool has an abstraction for it and have a way to use that
going forward and to track differences without any intermediate
abstractions.  I suppose in a way the version control's branch/rev/tag 
mechanism becomes an abstraction for the whole machine state at a point
in time.

I kind of lost track of this thread and missed any useful performance
information if you posted it.  Is this the same machine that has 
mysterious crashes?  If so, I would just give up, or replace the RAM and 
power supply and then give up.

Performance wise, what kind of load does it have?  Most servers that 
aren't doing graphics or number crunching are limited by disk i/o, not
cpu so the disks and controllers are the interesting things to compare
although if the controller requires a lot of CPU intervention (ide, sata
in some modes) it may look like a cpu problem.

You can boot about any Linux live or install CD that lets you get to the
shell (with a Centos install disk, enter 'linux rescue' at the boot
prompt) and use dd to copy the raw disk devices:
dd if=/dev/sda of=/dev/sdb bs=1M
Be sure you understand the device names for each disk. Using 'fdisk -l'
to see  the existing partition layout might help with that.

However, this is a slow process because the entire disk will be copied,
whether it is used or not.  If you are going to do it often, clonezilla 
is much faster because it knows enough about most linux and windows
filesystems to only copy the used part of the disk and can store
compressed image copies on a local or network disk.  The clonezilla-live 
version is a bootable CD (or USB image).  For larger scale cloning you 
can install the full version with DRBL for network booting into the
clone process. http://clonezilla.org/clonezilla-live/

If you have a popular server you can get what appear to be syn floods
from broken asymmetrical routing or bad firewall settings that permit
what would ordinarily be a normal number of client connection requests
to reach you but keep your response from getting back.  So the clients 
sit and retry, hammering you with syn's.

Yeah, but those don't stop when you replace the faulty RAM...  Mine did, 
but the errors committed to disk kept randomly re-appearing mysteriously
as the reads from the RAID1 alternated afterwards.

Yes, apparently RAM errors can be subtle and only appear when certain
adjacent bit patterns are stored - or when the moon is in a certain
phase or something.