[swinog] Virtualization for Webhosters / OpenVZ

2011-05-04 Diskussionsfäden Philip Iezzi
Hi

As a small web hosting provider we are planning to switch from physical-only 
servers to virtualization. So far, our favorite virtualization platform is 
OpenVZ under Debian Squeeze. We might consider running Proxmox as host system 
but prefer sticking with plain Debian (even though the future of the 
OpenVZ-kernel is not guaranteed). Our main goals: hardware independency, 
reliability, maintenance (single kernel virtualization), power efficiency 
(reduce number of physical servers), cost.

We're looking for a Swiss hosting provider who is actively using such a single 
kernel virtualization technology. What's your experience with OpenVZ? How about 
resource separation of containers (VPS)? Have you got any experience running 
complete containers off a NFS-mounted NAS/SAN? How about performance in a web 
hosting environment with resource peaks on various servers?
We would greatly appreciate if anybody could share his experience with OpenVZ 
(or similar single-kernel virtualization) and get in touch with us for some 
consulting.

Thanks.
Regards, Philip

--
DATENPARK
Badenerstrasse 69, Postfach
CH-8026 Zürich

Tel +41 44 299 33 66
Fax +41 44 299 33 91
i...@datenpark.ch   www.datenpark.ch

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Re: [swinog] Virtualization for Webhosters / OpenVZ

2011-05-04 Diskussionsfäden Viktor Steinmann

Dear Philip

While we're not a hosting provider, we still do have a lot of experience 
with virtualization platforms. We are currently running ~150 vSphere and 
Citrix XenServer servers and we've played around with Xen, KVM and others.


Two things I would like to give as advice:

- Storge is often underestimated. With virtualization you'll need a lot 
more storage throughput and access speed than with physical machines. 
NFS/NAS/iSCSI arenot a good ideas and are not a replacement for a real SAN.
- Networking and network separation is an important factor in virtual 
environments. You might keep an eye on that aspect as well.


Kind regards,
Viktor

On 04.05.2011 11:03, Philip Iezzi wrote:

Hi

As a small web hosting provider we are planning to switch from physical-only 
servers to virtualization. So far, our favorite virtualization platform is 
OpenVZ under Debian Squeeze. We might consider running Proxmox as host system 
but prefer sticking with plain Debian (even though the future of the 
OpenVZ-kernel is not guaranteed). Our main goals: hardware independency, 
reliability, maintenance (single kernel virtualization), power efficiency 
(reduce number of physical servers), cost.

We're looking for a Swiss hosting provider who is actively using such a single 
kernel virtualization technology. What's your experience with OpenVZ? How about 
resource separation of containers (VPS)? Have you got any experience running 
complete containers off a NFS-mounted NAS/SAN? How about performance in a web 
hosting environment with resource peaks on various servers?
We would greatly appreciate if anybody could share his experience with OpenVZ 
(or similar single-kernel virtualization) and get in touch with us for some 
consulting.

Thanks.
Regards, Philip

--
DATENPARK
Badenerstrasse 69, Postfach
CH-8026 Zürich

Tel +41 44 299 33 66
Fax +41 44 299 33 91
i...@datenpark.ch   www.datenpark.ch

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Re: [swinog] Virtualization for Webhosters / OpenVZ

2011-05-04 Diskussionsfäden Peter Rohrer
Hi Philip

Am Mittwoch, 4. Mai 2011 schrieb Philip Iezzi:
 We're looking for a Swiss hosting provider who is actively using such
 a single kernel virtualization technology. What's your experience
 with OpenVZ?
 
OpenVZ is running stable, I can't remember any outage because of OpenVZ.

 How about resource separation of containers (VPS)? 
 
Resource separation with the old (2.6.18, working up to the Lenny 
Release) kernel is ok concerning memory, CPU-time (and number of CPU 
Cores) as well as disk space. Disk IO is a different story (I think 
fair limiting of disk IO is hard to implement). The 2.6.18 Kernel no 
longer works with squeeze.
The stock Debian kernel is somehow of a step back, at the moment there 
is no absolute (Grant only 1 core to a virtual machine) limiting of 
CPUs or CPU time. Stability is still good, I haven't seen any crash 
because of OpenVZ.

 Have  you got any experience running complete containers off a
 NFS-mounted NAS/SAN?
 
There were some bugs with NFS (leading to kernel oops) in the Debian 
kernel. Please check the bug reports for more details, this may have 
been fixed with the point release. I have no experience with NAS/SAN.

 How about performance in a web hosting environment with 
 resource peaks on various servers?
 
We don't do dynamic reallocation of virtual servers based on load or 
resource peaks, if this was your question. Without a fast Disk 
subsystem, disk IO will most likely be the limiting factor, unless your 
software needs a lot of CPU. I can't tell how well the dynamic 
provisioning of various resources works, because we don't use that (We 
dont overbook our hardware, the customer always gets what he pays for).

Greetings,
Peter


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Re: [swinog] Virtualization for Webhosters / OpenVZ

2011-05-04 Diskussionsfäden Mathias Seiler
Hi Philip

Viktor's advice really sums it up. 

Since this is a network operator's list, I'll dig a little bit more into the 
network part:

You probably want to invest some time to separate the network, implement QoS, 
configure firewalls and design for redundancy (also first hop redundancy such 
as HSRP), especially if you use IP based storage on a shared network, depending 
on how reliable and secure you want your network to be.

Also if you grant control of the network interface to your clients (be it 
virtual or not) you probably want to take a look at private VLANs, ARP 
inspection, IP source guard and DHCP snooping or similar techniques to secure 
your network and prevent IP address waste.

Bear in mind that you may loose some functionality with such virtualization 
technologies like IPSec VPNs inside virtual containers ...


Oh and don't forget IPv6 :)

Regards
- Mathias

On 4 May 2011, at 11:03, Philip Iezzi wrote:

 Hi
 
 As a small web hosting provider we are planning to switch from physical-only 
 servers to virtualization. So far, our favorite virtualization platform is 
 OpenVZ under Debian Squeeze. We might consider running Proxmox as host system 
 but prefer sticking with plain Debian (even though the future of the 
 OpenVZ-kernel is not guaranteed). Our main goals: hardware independency, 
 reliability, maintenance (single kernel virtualization), power efficiency 
 (reduce number of physical servers), cost.
 
 We're looking for a Swiss hosting provider who is actively using such a 
 single kernel virtualization technology. What's your experience with OpenVZ? 
 How about resource separation of containers (VPS)? Have you got any 
 experience running complete containers off a NFS-mounted NAS/SAN? How about 
 performance in a web hosting environment with resource peaks on various 
 servers?
 We would greatly appreciate if anybody could share his experience with OpenVZ 
 (or similar single-kernel virtualization) and get in touch with us for some 
 consulting.
 
 Thanks.
 Regards, Philip
 
 --
 DATENPARK
 Badenerstrasse 69, Postfach
 CH-8026 Zürich
 
 Tel +41 44 299 33 66
 Fax +41 44 299 33 91
 i...@datenpark.ch   www.datenpark.ch
 
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Mathias Seiler

MiroNet GmbH, Strassburgerallee 86, CH-4055 Basel
T +41 61 201 30 90, F +41 61 201 30 99

mathias.sei...@mironet.ch
www.mironet.ch




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