1) a vCPU is akin to a process.
Yes
2) One can configure lots of VMs that will share the CPUs.
Yes
3) Do not overload the server by adding too many VMs that all want
resources. I assume top can be used to evaluate the amount of load
on
the server.
That's correct, you should see one "/usr/bin/kvm" process per vcpu if
you're using proxmox
3) When I configure a VM the amount of RAM is static (not shared).
If I
have 16GB of RAM then I realistically can only have around 12 - 14GB
of
RAM in use at any given time. That would be running VMs. I can
have
tons of VMs that are not running and not using resources/RAM and
their
RAM is no counted. Its the active VM's that count. RAM is not
shared.
The RAM _can_ be shared but that's dependent on the virtual machine
being configured properly. Linux, at least, automatically detects if
it's running in a virtual machine and enables what's called
"ballooning" to give back unused ram to the host. So again, as long as
you're able to keep the in use memory under your total memory you
should be fine.
A good rule of thumb though is, under normal load/usage, your in use
memory shouldn't exceed 50% of your total memory.
If you're going to run a Windows VM you'll want to make sure to
install the virtio drivers, of which Fedora provides a compiled
version of:
https://fedorapeople.org/groups/virt/virtio-win/direct-downloads/archive-virtio/virtio-win-0.1.229-1/
4) The amount of file space allotted to a VM is also static and is
taken
up even when the VM is off. For example if I have 10 VMs that are
assigned 20GB of disk space each, then that would total 200GB that
are
allocated and are always assigned and not shared with the other VMs.
Disk space is also tricky, you can either pre-allocate it, in which
case you're correct, or use "thin provisioning", where the VM will
only take up as much space on the host as used in the VM. Now, that
space will grow over time but will never shrink on its own, even if
you delete stuff from the VM. If you think of it as an SSD that needs
a periodic trim, it functions similarly. Coincidentally, if you use
Proxmox with either "raw" disk images or use ZFS, then you'll be able
to issue a trim command from the guest, which will release any unused
disk space back to the host. I personally run a trim on all my VMs
once every few months or so, or when I notice that a VM is taking up
much more space than is actually in-use in the VM.
You'll probably find some information saying that pre-allocating disk
space is better because it performs better, however I think that
advice is outdated especially if you're going to run the VMs on a good
quality SSD or NVME drive.
On Fri, Jul 21, 2023, at 8:02 AM, Keith Smith via PLUG-discuss wrote:
On 2023-07-20 16:25, Todd Cole via PLUG-discuss wrote:
I use a lot of proxmox servers and very happy with them most are
for
small office use running a router, win server and samba file
server
and a win 10 for remote users to vpn into
most of the hardware is used dell 4-6th gen I-7 (cheap 4 cores 8
virtual) with zfs raid 1 2 SSD's for redundancy and a spinner HDD
for
back up 32-64 gb ram and meet my needs
with ease. both at home and work.
I have used rack servers but they are hard to fit on a shelf, HOT
and
use a lot of power and sound like a jet taking off. (I have a few
to
donate free)
my point is do not over think or spend money to build a home lab
or
hardware that you will need to replace due to your use case.
I still have one on a duel core 8 gb ram 2 250GB spinning disks
that I
use as a router and zoneminder camera DVR in a un air conditioned
vacant office it just chugs along in 118 heat
I have a twin to it that is all set up ready to run that I would
be
willing donate also. Todd
---
I'm starting to understand what a vCPU is and that I really do not
need
a bunch of cores and threads. I have an old Dell i5 with 4 cores, 4
threads, 16GB of RAM, and a 1TB SSD.
I'm a PHP developer and use the Proxmox box for testing and
development.
Currently I have one LAMP VM configured.
This is what I come away with from this thread:
1) a vCPU is akin to a process.
2) One can configure lots of VMs that will share the CPUs.
3) Do not overload the server by adding too many VMs that all want
resources. I assume top can be used to evaluate the amount of load
on
the server.
3) When I configure a VM the amount of RAM is static (not shared).
If I
have 16GB of RAM then I realistically can only have around 12 - 14GB
of
RAM in use at any given time. That would be running VMs. I can
have
tons of VMs that are not running and not using resources/RAM and
their
RAM is no counted. Its the active VM's that count. RAM is not
shared.
4) The amount of file space allotted to a VM is also static and is
taken
up even when the VM is off. For example if I have 10 VMs that are
assigned 20GB of disk space each, then that would total 200GB that
are
allocated and are always assigned and not shared with the other VMs.
---
OK, another question. If commercial rack mount servers are so noisy
and
use a lot of electricity... then why not use consumer grade
computers?
Around 2005/2006 I was working as a level 1 at iPower. A manager
showed
us some pictures of the server room in downtown L.A. and they had a
ton
of HP mini towers on storage racks that were being used as hardware
servers for hosting. I think they called them dedicated servers.
---
On Thu, Jul 20, 2023 at 3:09 PM George Toft via PLUG-discuss
<plug-discuss@lists.phxlinux.org> wrote:
Be very careful with ESX. I know someone who bought a random
server
and ESX7 was not supported. It used to run on anything, now, not
so
much. Check the support matrix before you buy.
Regards,
George Toft
On 7/20/2023 1:12 PM, greg zegan via PLUG-discuss wrote:
Hello,
I appreciate this topic. I have been wondering for a while now
if there is an affordable home server out there for EXSi and
such.
Is there any way for someone to come up with a few choices for
people like me? Is there a low end, mid range, and high end
home
server for someone to list with parts or suggested parts?
thanks,
Greg
On Thursday, July 20, 2023 at 01:01:13 PM MST, Keith Smith via
PLUG-discuss <plug-discuss@lists.phxlinux.org> wrote:
Thanks!!
On 2023-07-20 11:36, Ryan Petris via PLUG-discuss wrote:
I personally wouldn't even go for a used server. They're
generally
loud, and even when they aren't they use much more electricity
than
what you would get from a consumer platform. There's really no
benefit
unless you have room in your house to make a real server room
with
racks and the electrical capacity to go along with it.
On Thu, Jul 20, 2023, at 10:59 AM, Stephen Partington wrote:
the downside for these processors is their mainboards are
still
very
pricy to buy. much more than the CPU itself. you are almost
better
off looking for and buying a refurbished server which you can
get
for almost ludicrously inexpensive prices.
On Thu, Jul 20, 2023 at 1:56 PM Ryan Petris via PLUG-discuss
<plug-discuss@lists.phxlinux.org> wrote:
The CPU's cheap because it's old and no one wants them anymore
--
it's of the same generation as 6000 series intel processors
(i.e.
skylake). It also uses a server socket, so the only
motherboards
you're going to be able to find are server motherboards. Those
are
going to be expensive and/or have other quirks, such as
requiring a
vendor specific heatsink, or a vendor-specific power supply,
or
take
5 minutes to start up, etc.
You'd be better off spending money on a last-gen cpu and
motherboard, for instance here's a combination that is
relatively
cheap:
$174 for an i5-12400, which according to cpubenchmark.net [1]
[1] is
nearly 30% faster than the Xeon you linked (score of 19501 vs
15146,
much faster single-core score as well):
https://www.amazon.com/Intel-i5-12400-Desktop-Processor-Cache/dp/B09NMPD8V2/
$139 for a compatible motherboard:
https://www.amazon.com/GIGABYTE-B760M-DS3H-AX-Motherboard/dp/B0BSP61QZC/
I also wouldn't pay so much attention to the number of
"threads" you
think you'll need; you can run many VMs with a total number of
virtual processors that is much more than what you actually
have,
and as long as you're not trying to go whole hog on every
machine at
the same time you'll be fine, and even if you do, you'll still
be
better off with a faster processor with a few fewer threads
than an
older slower cpu with more.
On Thu, Jul 20, 2023, at 10:26 AM, Keith Smith via
PLUG-discuss
wrote:
Hi,
I was surfing the Inter Web when I happened upon a Xeon server
CPU.
It
is marked at $32.49 at Newegg. It has 12 cores and 24 threads
and
has a
good benchmark score.
https://www.cpubenchmark.net/cpu.php?cpu=Intel+Xeon+Silver+4116+%40+2.10GHz&id=3179
https://www.newegg.com/p/274-000A-007K2?Description=Xeon
In the future at some point I would like to build something
with 20
plus
or minus cores and 40 threads more or less for Proxmox. This
would
be
over kills because I only need 1 or 2 VMs active at one
time...
maybe 3
in an extreme situation.
This 12 core/24 thread CPU with 64Gb of Ram and a 1Tb SSD
would
really
be more resources than I would ever need. Off the top of my
head
this
means I might be able to build a decent Proxmox server for
$500
-
$600.
I do not need fancy video except for one VM that might be
running
Win 10
or 11... I assume a server grade CPU would handle Win 10 and
11?
Am I on the right track?
Thank You For Your Feedback!!
Keith
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--
A mouse trap, placed on top of your alarm clock, will prevent
you from
rolling over and going back to sleep after you hit the snooze
button.
Stephen
Links:
------
[1] http://cpubenchmark.net
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--
Todd Cole
Ubuntu Arizona Team
2928 W El Caminito
Phoenix AZ 85051-3957
to...@azloco.com
602-677-9402
Links:
------
[1] http://cpubenchmark.net
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