Xen users - Jun 2007 - Migration form Xensource to XenExpress and FC / iSCSI trouble

Dear all,

after 1 year testing with xensource and three servers (8 VMs, all linux) 
at a small university laboratory I''m evaluating to migrate to the 
commercial version of the product with support, and build a SAN which 
will host our VMs.

I''have just few questions.... :-)

The FAQs says clearly that "there are no automated tools to migrate 
XenSource VMs to XenExpress/Server/Enterprise".
Is there any "unofficial" procedure to do that manually? (i.e. create
a
VM with the console and then dd the old VM img file to the newly created 
LVdisk) ?  The main problem is that most VMs are RHEL 3 (unless they''re
running 2.6.6-xen smoothly).

Even do we actually have small VMs with no production stress of I/O and 
network on them, I want to design the SAN smartly. I''m considering
iSCSI
only for budget issues. I plan to have 2-3 Xen host with a total of 
10-15 VMs.

Is this possible with iSCSI?
Are out there real world cases I may compare with?
In other way, should I go for fibre channel anyway or how can I evaluate 
the trade-off between the two solutions?

I decided for a SAN also to facilitate backup of my VMs so the idea is 
to have no or really small disks on the Xen host. Is this good in your 
experience or should I have anyway my VMs on LVM on Xen host disks?

Maybe the latter depend on choosing between iSCSI and fibre channel?

I don''t want to start a flame on that but I''m also in trouble
deciding
between Dell, IBM and HP (I''ve one or two HP DL380G3 that I will
recycle
in the infrastructure)... any suggestion or real world experience will 
be appreciated.

Thank you in advance.

	Ivan



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Dear all,

I don''t know if my question was out of topic for the list, or presented
in a wrong way. If yes, please let me known.
I can imagine that the latter part of the mail (HP vs Dell vs IBM SAN) 
could be not politically correct, and thus not answered at all, but the 
former one (Fibre Channel vs iSCSI and xensource to xenexpress 
migration) may be of some interest and at least for the 
xensource/xenexpress part it seems to me it has not been answered yet in 
the list.

thank you in advance, any hint is appreciated. Should I split my mail in 
three different mail?

	ivan

Ivan Porro wrote:
> Dear all,
> 
> after 1 year testing with xensource and three servers (8 VMs, all linux) 
> at a small university laboratory I''m evaluating to migrate to the 
> commercial version of the product with support, and build a SAN which 
> will host our VMs.
> 
> I''have just few questions.... :-)
> 
> The FAQs says clearly that "there are no automated tools to migrate 
> XenSource VMs to XenExpress/Server/Enterprise".
> Is there any "unofficial" procedure to do that manually? (i.e.
create a
> VM with the console and then dd the old VM img file to the newly created 
> LVdisk) ?  The main problem is that most VMs are RHEL 3 (unless
they''re
> running 2.6.6-xen smoothly).
> 
> Even do we actually have small VMs with no production stress of I/O and 
> network on them, I want to design the SAN smartly. I''m considering
iSCSI
> only for budget issues. I plan to have 2-3 Xen host with a total of 
> 10-15 VMs.
> 
> Is this possible with iSCSI?
> Are out there real world cases I may compare with?
> In other way, should I go for fibre channel anyway or how can I evaluate 
> the trade-off between the two solutions?
> 
> I decided for a SAN also to facilitate backup of my VMs so the idea is 
> to have no or really small disks on the Xen host. Is this good in your 
> experience or should I have anyway my VMs on LVM on Xen host disks?
> 
> Maybe the latter depend on choosing between iSCSI and fibre channel?
> 
> I don''t want to start a flame on that but I''m also in
trouble deciding
> between Dell, IBM and HP (I''ve one or two HP DL380G3 that I will
recycle
> in the infrastructure)... any suggestion or real world experience will 
> be appreciated.
> 
> Thank you in advance.
> 
>     Ivan
> 
> 
> 

-- 
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voice: +39 010 353 2789
fax:   +39 010 353 2948

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> -----Original Message-----
> From: xen-users-bounces@lists.xensource.com 
> [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of Ivan Porro
> Sent: 02 July 2007 16:56
> To: xen-users@lists.xensource.com
> Subject: Re: [Xen-users] Migration form Xensource to 
> XenExpress and FC / iSCSI trouble
> 
> Dear all,
> 
> I don''t know if my question was out of topic for the list, or 
> presented 
> in a wrong way. If yes, please let me known.
Not sure. I just didn''t answer because I ditn''t seem to see
anything in
the question that I could actaully answer. 
> I can imagine that the latter part of the mail (HP vs Dell vs 
> IBM SAN) 
The type of question (regarding brands have been asked before). I think
SAN is pretty much "you get what you pay for - add a little extra if you
want big brandnames", and it''s mostly a case of which vendor you
like/dislike which to go for - and of course, if you buy a set of
servers from one company, you have less of a risk of "bouncing between
vendords" if your SAN is also from the same vendor - none of if you have
a server from X: "Well, it''s probably the SAN that is broken, go
to Y",
and then SAN-supplyer Y saying "Well, it''s not our SAN that is
faulty,
go back to X" - you probably already knew this, but just in case. 
> could be not politically correct, and thus not answered at 
> all, but the 
> former one (Fibre Channel vs iSCSI and xensource to xenexpress 
> migration) may be of some interest and at least for the 
> xensource/xenexpress part it seems to me it has not been 
> answered yet in 
> the list.
Questions on XenExpress are probably best asked on the XenExpress forum:
http://forums.xensource.com/index.jspa
[And I would be VERY surprised if XenExpress doesn''t have tools to
support such migration - that would be like saying "Since you bought a
used Ford from a non-Ford dealership, we won''t help you buying a brand
new one from our Ford Dealership here".

I''m sure the iSCSI vs. FC is a relevant one (at least to some extent),
but I can''t offer any real advice. 

For future questions, I would suggest that you ask one type of question
in one mail - then perhaps people who skip your entire mail because they
think "someone else will come along and answer the whole mail" will be
more enticed about answering a particular question that they know a lot
about. 

[I answer many questions each day, but I don''t answer every question
that is asked]. 

--
Mats



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