[mdlug] Virtual Server Time

[Robert Adkins II]

> Robert Adkins II wrote:
> >> If the
> >> goal is to recover from a borked host quickly, shared 
> storage makes 
> >> more sense.  We can discuss this further if desired.
> >
> > 	I would like to learn more about NAS, it's just not 
> been something 
> > high on my list, as the pricing had been out of reach of the budget 
> > that I typically have available. It's a very interesting 
> concept and I 
> > think it would suit my needs quite well. I believe there is 
> also some 
> > additional benefit with backing up data, data throughput and 
> > restoring/replacing the NAS in cases of catastrophic failure.
> 
> NAS options for the small scale would include small devices 
> that hold 4 drives, a dedicated server, or even just 
> selecting glusterfs for the hosts.  There are more expensive 
> options, but this isn't bad for a starting point.
> 
> >> This would not be needed if you have shared storage and 
> you keep your 
> >> servers running.  Otherwise you'd just need instructions 
> to power on 
> >> the reserve server and do everything else remotely.
> >
> > 	This is another benefit of NAS that I would be 
> interested in learning 
> > more about.
> 
> As long as you have access by ssh to each of your hosts, you 
> can run commands to move a guest from one host to another.
> While a "live migration" would require expensive hardware, 
> you could rather easily connect to a live server and start a 
> guest which had been running on another host.
> 
> >> My first suggestion is to be sure to use LVM on any and all 
> >> partitions of your physical hard drives (with the notable 
> exception 
> >> of /boot).  If possible, keep between 20% and 40% unused 
> so you can 
> >> expand partitions as needed.
> >>
> >
> > 	LVM on the Virtual Machines or on the drives that will 
> hold the VMs 
> > or the drives that will hold the data? I have been using a very 
> > effective for me drive layout for a little over 10 years now, it's 
> > evolved slightly, but I have never run into any issues with 
> it. There 
> > are probably a few ways to do some elements better though.
> 
> I recommend it for both hosts and guests.  LVM provides 
> options like resizing partitions and hot migration of a failing disk.
> All you need to do is extend a / partition live on a 
> produciton server one time, and you'll be sold!
> 
> > 	This is how I intend on configuring the VMs
> >
> > 	1. Email/Proxy Server/DNS
> > 		This one will handle the basic MTA, the IMAP 
> service, DNS and run 
> > Squid. It's going to be one of two machines that can "see" 
> outside of 
> > the network.
> >
> > 	2. SSL Email Server
> > 		I am particular to a particular MTA and it's 
> going to be easier, for 
> > now, to setup a MTA that uses SSL asa  "full" separate server.
> > This one will also "see" outside of the network.
> >
> > 	3. File Server/Account Management Server
> > 		Windows Domain Controller and I plan on 
> consolidating all user 
> > account information onto this server as well with all other 
> VMs asking 
> > this server for user authentication.
> 
> This plan looks good.  The only thing I would do is set up 
> the DC first and see what resources it eats up.  Give it at 
> least a week and analyze sar data carefully.  Depending on 
> the number of users and the usage, you may not want to add 
> the other vms to this host.
> 
> c

  I forsee no issues, there's approximately 15 active users on the network
and 20 PCs total that connect to the domain. If I was dealing with more than
30 users, I would consider looking into more powerful server hardward and
setting up the VM for the fileserver to use two CPUs and quite a bit of RAM.

  If not for hardware failures, I could continue to service my users
effectively on an older piece of hardware.

  I do intend on doing some testing across the network with small, medium
and large file opening/saving to the VM Samba server that, for now, will
have access to an internal drive on the host. If there's no appreciable
difference, I should be fine.

  I do think, that I should look into an easy to setup/configure NAS system
that can be subordinate to my Samba Domain Controller, before moving forward
with the migration to Virtual Servers. My main concern right now is the
potential failure of the hard drives in my current server hardware.

Rob