Virtual Server Solution and OS

[Jonathan Mason]

Hi Victor,

With ext3 on CentOS (4.x iirc) and the way the VMs had been setup on 
VMware server in Windows 2003 the performance was not acceptable. The 
VMs were created as growing single file 'disks' ranging from 5GB to 
50GB, this led to terrible fragmentation on ext3. I think things would 
have performed adequately if the disks had been pre-allocated, disks 
were split into multiple files and/or a different file system had been 
used with better support for large files. Unfortunately we couldn't 
pre-allocate disks because with the number of VMs and their disks there 
wasn't enough space.

In our configuration RAM and CPU power were quite adequate, it was only 
IO that made the system really slow down (which with our workload was 
90% of the time).

So if you choose to use VMware on a Linux host I would really recommend 
using ext4 or XFS.

I would probably go with an ESXi solution though, it would probably 
scale better / have more support.

Jonathan

Victor Mendonça wrote:
> Hi Jonathan, thanks for the reply.
>
> I'm aware that ESXi is a bare-metal solution, but I thought I'd include
> which OS I was leaning to in case I do decide for another Virtual
> Solution other than ESXi.
>
> I think VirtualBox is a great desktop app as it stands right now, but it
> still lacks the needs for an enterprise environment. Correct if I'm
> wrong, but VirtualBox still does not have a remote management interface
> (other than cli) and user roles, which will be important for us.
>
> It seems that the environment that you had was very similar to what I
> need (in regards to systems performance needs). Did you think that with
> the hardware you were using most machines ran properly, or was there
> still some room/need for performance boost?
>
>
> Victor Mendonça
> http://wazem.org/
>
>    ,____________,
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>
> -----Original Message-----
> From: Jonathan Mason <jonathan.mason at gmx.net>
> Reply-to: The Canadian Ubuntu Users Community
> <ubuntu-ca at lists.ubuntu.com>
> To: The Canadian Ubuntu Users Community <ubuntu-ca at lists.ubuntu.com>
> Subject: Re: Virtual Server Solution and OS
> Date: Sat, 06 Jun 2009 14:08:36 -0400
>
> Victor Mendonça wrote:
>   
>> Greetings!
>>
>> I will be implementing a virtual sever solution at work and I'm trying 
>> to get as many facts as possible for the best setup.
>>
>> We want to setup a server at our support department to host a minimum 
>> of 8x Windows machines running simultaneously (ranging from XP up, 
>> including server, 32 and 64-bit). Some of these machines might run 
>> MSSQL which will increase the overhead, however they will be used for 
>> testing and bug replication only, so there is no need for them to be 
>> lightning fast.
>>
>> The department could grow and the number of virtual machines might 
>> increase in the future (let's say 3x additional machines).
>>
>> There's also a need for backup, user management and remote management. 
>> Costs need to be kept as low as possible, while still providing a good 
>> and acceptable performance. Also, the company does not have a formal 
>> Linux guy, so they might need to outsource support if I ever leave the 
>> company.
>>
>> I've been doing some research on the following OS's and Virtual Server 
>> solutions, including cost, support, usability and other aspects:
>>
>>
>> => OS
>> -CentOS
>> -Ubuntu
>> -Suse
>> -Open Suse
>> -Open Solaris
>>
>> => Virtual Severs
>> -Vmware Server
>> -Vmware ESXi
>> -VirtualBox
>> -Xen
>> -KVM
>>
>>
>> My choices are going for VMware ESXi and either CentOS or OpenSuse 
>> (even thou I'm an Ubuntu guy).
>>
>> Any ideas and/or comments are very welcome!
>>
>> -- 
>>
>> Victor Mendonça
>> http://wazem.org
>>
>>    ,____________,
>>    .'          '.
>>   /~~~~^~~~^~^~~~\
>>  /      _    /||  \
>> ;      ( }   \||D  ;
>> |    | /\__,=[_]   |
>> ;  ( |_\_  |---|   ;
>>  \  )|  |/ |   |  /
>>   '. |  /_ |   |.'
>>    '------------'
>>       
>>         
>>
>>
>>     
> If you're going with VMware ESXi then you won't be needing a host OS. 
>  From what I understand ESX is a bare-metal solution, it IS the host OS.
>
> When I was doing some sysadmin stuff for a small software company I 
> tried migrating their VM server from Win2K3 with VMware server to CentOS 
> + VMware server but unfortunately the switch over didn't work, there 
> were huge problems with very slow IO. I would probably recommend ESXi, 
> since it was designed from the ground up for virtualization I would 
> think it is the best performance wise. Also third-party support is 
> probably going to be easiest with VMware. The problem with VMware ESX is 
> probably going to be hardware though, when I was looking into 
> virtualization with VMware ESX their HCL was quite narrow and didn't 
> provide support for any SATA controllers, the only options were SCSI and 
> iSCSI.
>
> To provide a bit of background the VM server I was trying to transition 
> was running 4 - 7 Win2K3 VMs, 2 CentOS VMs and 1 or 2 XP VMs on a dual 
> opteron dual-core machine (4x 1.83GHz), 8GB ECC DDR2 with a HighPoint 
> RocketRAID controller set-up in a raid-5 array. These VMs were 
> configured as build servers and test environments along with the main MS 
> SQL 2005 server for the company. There would be at least 6 VMs running 
> at all times and then additional VMs would be started on demand. I 
> hypothesized that the scalability problem we had was with fragmentation 
> with the original VMs being created as single-files which would grow as 
> required on ext3. If you go with a linux host OS I would recommend going 
> with ext4 if possible because the bottleneck in any VM server is 
> probably going to be IO. Preallocation of the file systems would 
> probably improve performance.
>
> I've been using VirtualBox for the past couple years on my laptop to 
> virtualize Windows XP for my university work, it is also a great tool 
> but I don't know how well it might scale for a server configuration. 
> When I was running 3 or 4 VMs I was quickly exhausting my 2GB of ram and 
> even with VT-enabled the performance on my Core2Duo T7200 was quite 
> slow. I would definitely recommend it as a good alternative to VMware 
> workstation but I would recommend a lot of testing before trying to roll 
> it out in a server.
>
> Jonathan
>
>
>
>