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Old 03-03-2010, 01:12 PM
David Milholen
 
Default New to VM

What are some min requirements for Hardware and what performance
differences are there in just running another pid for an app?



*

--


David Milholen

Project Engineer

501-318-1300

Wireless Etc








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Old 03-03-2010, 01:53 PM
Les Mikesell
 
Default New to VM

David Milholen wrote:
> What are some min requirements for Hardware and what performance
> differences are there in just running another pid for an app?

That question is way too general to answer and also depends a bit on what VM
approach (xen/kvm/vmware server, vmware esxi) you use. As a rule of thumb, I'd
expect to lose 10% in overall performance and much more than that from disk head
contention unless you plan the layout very carefully and spread over independent
drives. You can make some (perhaps more than that) back by overcommitting the
machines where the load is likely to be bursty and staggered and by having a lot
of RAM for better disk buffering.

--
Les Mikesell
lesmikesell@gmail.com



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Old 03-03-2010, 07:40 PM
David Milholen
 
Default New to VM

For example if i have 2 ibm Eserver 326 with dual xeon 2.8ghz each with
2 sata 200Gb drives.

how many virtual machines can be configured on those to run a couple of
mail servers and some network monitoring like ntop/nagios

possibly add domain hosting services on there also?



--dave



Les Mikesell wrote:

David Milholen wrote:


What are some min requirements for Hardware and what performance
differences are there in just running another pid for an app?



That question is way too general to answer and also depends a bit on what VM
approach (xen/kvm/vmware server, vmware esxi) you use. As a rule of thumb, I'd
expect to lose 10% in overall performance and much more than that from disk head
contention unless you plan the layout very carefully and spread over independent
drives. You can make some (perhaps more than that) back by overcommitting the
machines where the load is likely to be bursty and staggered and by having a lot
of RAM for better disk buffering.







--


David Milholen

Project Engineer

501-318-1300

Wireless Etc








_______________________________________________
CentOS mailing list
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http://lists.centos.org/mailman/listinfo/centos
 
Old 03-03-2010, 07:53 PM
"Joseph L. Casale"
 
Default New to VM

>For example if i have 2 ibm Eserver 326 with dual xeon 2.8ghz each with 2 sata 200Gb drives.

Not much if there's any IO at all, those sata drives will not
do much for performance. I have a variety here of sata and SAS
and even on good controllers, the sata drives obviously just
don't handle much.

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Old 03-03-2010, 08:12 PM
Les Mikesell
 
Default New to VM

On 3/3/2010 2:40 PM, David Milholen wrote:
> For example if i have 2 ibm Eserver 326 with dual xeon 2.8ghz each with
> 2 sata 200Gb drives.
> how many virtual machines can be configured on those to run a couple of
> mail servers and some network monitoring like ntop/nagios
> possibly add domain hosting services on there also?

That's still not enough information to be useful since there can be
several orders of magnitude in difference in the load of servers like
that. I have a similar vintage machine with 4 gigs RAM and 6 scsi
drives running 3 low-usage servers under vmware server plus a slightly
busier mail server on the native host, but that wouldn't work for a busy
domain, especially if you are doing spam scanning on the email.

In my case I was moving stuff that ran on older pentium 3 boxes with 1
gig RAM so the VM's were about equivalent. You'll have trouble doing
much with just 2 SATA drives, though.

--
Les Mikesell
lesmikesell@gmail.com

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Old 03-04-2010, 02:32 AM
David Milholen
 
Default New to VM

Ok,

*So the idea on VM is to have plenty of Drive space? Please excuse my
obvious lack of knowledge on VM but I am so old school just having a
single server with just a few drives only running a few

Apps like Httpd,mysqld,qmt-plus and dns.

I have managed these for so long on just a couple of machines but
technology is changing and we are growing as a company and I have heard
and read great things that can be done with VM.

I have another ibm Eserver with a couple of scsi 15k 50GB drives and 4
GB of memory that I can configure from scratch to do VM or what ever I
need.

*I guess I should start by asking how VM is configured and How does
allocate resources on the server?

*BTW I am a big fan of this list and have been for quiet some time.

*--Dave





Les Mikesell wrote:

On 3/3/2010 2:40 PM, David Milholen wrote:


For example if i have 2 ibm Eserver 326 with dual xeon 2.8ghz each with
2 sata 200Gb drives.
how many virtual machines can be configured on those to run a couple of
mail servers and some network monitoring like ntop/nagios
possibly add domain hosting services on there also?



That's still not enough information to be useful since there can be
several orders of magnitude in difference in the load of servers like
that. I have a similar vintage machine with 4 gigs RAM and 6 scsi
drives running 3 low-usage servers under vmware server plus a slightly
busier mail server on the native host, but that wouldn't work for a busy
domain, especially if you are doing spam scanning on the email.

In my case I was moving stuff that ran on older pentium 3 boxes with 1
gig RAM so the VM's were about equivalent. You'll have trouble doing
much with just 2 SATA drives, though.





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Old 03-04-2010, 02:41 AM
"nate"
 
Default New to VM

David Milholen wrote:
> I have managed these for so long on just a couple of machines but
> technology is changing and we are growing as a company and I have heard
> and read great things that can be done with VM.

Really depends on how much usage the systems get, if you are migrating
from physical systems to virtual systems look at the CPU, load, and
i/o(if linux use iostat). I run vmware server on a 5-year old system
which has 2 VMs on it, runs apache, mysql, mail services, dns, and
a bunch of other small things. Works fine, though my typical CPU
usage on the *host* is 5%. Running off a pair of 250GB SATA drives
connected to a 3Ware 8006-2 RAID card. Dual Xeon 3Ghz, 6GB ram, 32-bit.

In my experience most systems like the ones your using hosting
the apps you mention are idle 99%+ of the time, making them perfect
VM candidates.

> I have another ibm Eserver with a couple of scsi 15k 50GB drives and 4
> GB of memory that I can configure from scratch to do VM or what ever I need.
> I guess I should start by asking how VM is configured and How does
> allocate resources on the server?

Resource allocation depends on the VM technology your using, myself
I am a long time VMware fan/user, so I stick to their stuff, but
no matter what it really depends on how much load your system will
be under.

>From a VMware perspective, this PDF is informative, but probably
well beyond the scale your operating at, you can get an idea as
to the complexity that "virtualization" entails.

http://portal.aphroland.org/~aphro/vmware/09Q3-perf_overview_and_tier1-pac_nw.pdf

Performance of bare metal hypervisors like VMware ESX will
dramatically outperform the hypervisors that run on top of
another OS(I think they call them "type 2") like VMware server.
But bare metal hypervisors have very strict hardware requirements.
I use VMware server on my own system since the hardware is not
supported by ESX.

At my full time job I run dozens of ESX systems on real hardware,
with a proper SAN and networking infrastructure.

nate

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Old 03-04-2010, 02:59 AM
David Milholen
 
Default New to VM

Nate,

*That pdf resolved a bunch of questions I had..

Thanks, now I have a focus and some new toys to play with.

*I am going to configure a VM and have a snapshot of the Native
QMT-PLUS server and let the VM do all of the backups to the NAS.

If all goes well the goal will be to have a 2 machines and both set up
to do VM doing replication for the mail services.

--Dave





nate wrote:

David Milholen wrote:


I have managed these for so long on just a couple of machines but
technology is changing and we are growing as a company and I have heard
and read great things that can be done with VM.



Really depends on how much usage the systems get, if you are migrating
from physical systems to virtual systems look at the CPU, load, and
i/o(if linux use iostat). I run vmware server on a 5-year old system
which has 2 VMs on it, runs apache, mysql, mail services, dns, and
a bunch of other small things. Works fine, though my typical CPU
usage on the *host* is 5%. Running off a pair of 250GB SATA drives
connected to a 3Ware 8006-2 RAID card. Dual Xeon 3Ghz, 6GB ram, 32-bit.

In my experience most systems like the ones your using hosting
the apps you mention are idle 99%+ of the time, making them perfect
VM candidates.



I have another ibm Eserver with a couple of scsi 15k 50GB drives and 4
GB of memory that I can configure from scratch to do VM or what ever I need.
I guess I should start by asking how VM is configured and How does
allocate resources on the server?



Resource allocation depends on the VM technology your using, myself
I am a long time VMware fan/user, so I stick to their stuff, but
no matter what it really depends on how much load your system will
be under.

>From a VMware perspective, this PDF is informative, but probably
well beyond the scale your operating at, you can get an idea as
to the complexity that "virtualization" entails.

http://portal.aphroland.org/~aphro/vmware/09Q3-perf_overview_and_tier1-pac_nw.pdf

Performance of bare metal hypervisors like VMware ESX will
dramatically outperform the hypervisors that run on top of
another OS(I think they call them "type 2") like VMware server.
But bare metal hypervisors have very strict hardware requirements.
I use VMware server on my own system since the hardware is not
supported by ESX.

At my full time job I run dozens of ESX systems on real hardware,
with a proper SAN and networking infrastructure.

nate

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CentOS mailing list
CentOS@centos.org
http://lists.centos.org/mailman/listinfo/centos




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Old 03-04-2010, 03:42 AM
Les Mikesell
 
Default New to VM

David Milholen wrote:
> Ok,
> So the idea on VM is to have plenty of Drive space?

Not space so much as independently-seeking heads. Every process on every
virtual/real machine that shares a physical drive is going to have its own idea
about where the head is supposed to be at the moment and you end up waiting as
they fight over it.

> Please excuse my
> obvious lack of knowledge on VM but I am so old school just having a
> single server with just a few drives only running a few
> Apps like Httpd,mysqld,qmt-plus and dns.
> I have managed these for so long on just a couple of machines but
> technology is changing and we are growing as a company and I have heard
> and read great things that can be done with VM.

On a small scale there are only a couple of advantages. You can take advantage
of more powerful hardware by migrating older systems to fewer boxes, maintaining
the old setup and IP addresses, and the virtual machines can be moved around to
different physical hosts without much regard to hardware differences.

> I have another ibm Eserver with a couple of scsi 15k 50GB drives and 4
> GB of memory that I can configure from scratch to do VM or what ever I need.
> I guess I should start by asking how VM is configured and How does
> allocate resources on the server?

I mostly use VMware Server, but the systems were set up before the ESXi product
was free. Starting over, I'd install ESXi on the bare metal, then whatever you
want as guests. You do need a windows machines to run the console client for
ESXi, though.

--
Les Mikesell
lesmiksell@gmail.com

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Old 03-04-2010, 04:39 AM
John R Pierce
 
Default New to VM

Les Mikesell wrote:
> I mostly use VMware Server, but the systems were set up before the ESXi product
> was free. Starting over, I'd install ESXi on the bare metal, then whatever you
> want as guests. You do need a windows machines to run the console client for
> ESXi, though.
>


vmware esxi *so* outperforms vmware server, its not funny.

I've also found server 2.0.x to be a little unstable on several
different hosts (both windows and linux)


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