hyper-v

[cptkirkh]

I am about to venture off into hyper-v land. I want to start by
runnign a consolidated configuration. By this i mean placing about 6
VMs on a strong box. These VMs will host only small apps that our
company runs. I am not planning on putting exchange or SQL server on
here, My server reseller wants me to buy a iscsi box to put the vms
on he says it willrun faster. The problem is i am on a budget and
can't afford a iscsi box. If i put my host box with RAID 1 for theOS
and then RAID 5 for the vm files and being htese are only small app
servers will that work or am i crazy? Thnaks for your advice.

 

[Meinolf Weber [MVP-DS]]

Hello cptkirkh,

They will run if the server performance is high enough ofcourse (CPUs and
RAM), but RAID 5 is not that fast, biggest advantage of RAID 5 is fault tolerance,
therefore it counts a check sum for each data and stores the checksum also
to be able to rebuilt a broken disk during each saving step, this slows down.

Best regards

Meinolf Weber
Disclaimer: This posting is provided "AS IS" with no warranties, and confers
no rights.
** Please do NOT email, only reply to Newsgroups
** HELP us help YOU!!! http://www.blakjak.demon.co.uk/mul_crss.htm


> I am about to venture off into hyper-v land. I want to start by
> runnign a consolidated configuration. By this i mean placing about 6
> VMs on a strong box. These VMs will host only small apps that our
> company runs. I am not planning on putting exchange or SQL server on
> here, My server reseller wants me to buy a iscsi box to put the vms
> on he says it willrun faster. The problem is i am on a budget and
> can't afford a iscsi box. If i put my host box with RAID 1 for theOS
> and then RAID 5 for the vm files and being htese are only small app
> servers will that work or am i crazy? Thnaks for your advice.
>

 

[Bill Grant]

"cptkirkh" wrote in message
news:3afd5e0b-00e9-42f4-9fb7-ece20eafbf6e@d4g2000yqa.googlegroups.com...
> I am about to venture off into hyper-v land. I want to start by
> runnign a consolidated configuration. By this i mean placing about 6
> VMs on a strong box. These VMs will host only small apps that our
> company runs. I am not planning on putting exchange or SQL server on
> here, My server reseller wants me to buy a iscsi box to put the vms
> on he says it willrun faster. The problem is i am on a budget and
> can't afford a iscsi box. If i put my host box with RAID 1 for theOS
> and then RAID 5 for the vm files and being htese are only small app
> servers will that work or am i crazy? Thnaks for your advice.

If you are really interested in speed, the vms would run fastest if you
had multiple spindles on the host and stored the vhd file for each vm on its
own physical hard drive, separate from the system disk of the host. But that
is not necessarily the best way to go. There is more involved here than disk
speed.

 

[DaveMills]

On Mon, 27 Jul 2009 07:27:54 +0000 (UTC), Meinolf Weber [MVP-DS]
wrote:

>Hello cptkirkh,
>
>They will run if the server performance is high enough ofcourse (CPUs and
>RAM), but RAID 5 is not that fast, biggest advantage of RAID 5 is fault tolerance,
>therefore it counts a check sum for each data and stores the checksum also
>to be able to rebuilt a broken disk during each saving step, this slows down.

I would look at the Raid 5 this way:
Every write will require that the CRC is recalculated and the redundant stripe
written. So if your strip size is 64K you will need to write a 64 stripe segment
for the data that changes and an additional segment for the data in the CRC.
Thus 2x64k even if only one 4KB cluster changes. This overhead is substantial
but may be swallowed by the local processing capacity of the Raid controller
with an operational cache. For a non raid stripe (e.g Mirror) there are two
writes of 1 cluster and the system can relax a bit once the first is done.

So for example a raid 5 is not good for a log file which gets a little bit of
data added frequently and sequentially so requires a lot of writes but for a
large database where the access is more random the overhead is not so large
because the access is not small sequential writes but more random reads and
occasional writes.

To work it all out you need to understand the data structures on the raid, the
performance characteristics of the raid controller and the way the applications
will use the disk subsystem. Different applications will be optimal of different
disk configurations.

>
>Best regards
>
>Meinolf Weber
>Disclaimer: This posting is provided "AS IS" with no warranties, and confers
>no rights.
>** Please do NOT email, only reply to Newsgroups
>** HELP us help YOU!!! http://www.blakjak.demon.co.uk/mul_crss.htm
>
>
>> I am about to venture off into hyper-v land. I want to start by
>> runnign a consolidated configuration. By this i mean placing about 6
>> VMs on a strong box. These VMs will host only small apps that our
>> company runs. I am not planning on putting exchange or SQL server on
>> here, My server reseller wants me to buy a iscsi box to put the vms
>> on he says it willrun faster. The problem is i am on a budget and
>> can't afford a iscsi box. If i put my host box with RAID 1 for theOS
>> and then RAID 5 for the vm files and being htese are only small app
>> servers will that work or am i crazy? Thnaks for your advice.
>>
>
--
Dave Mills
There are 10 types of people, those that understand binary and those that don't.

 

[Brooke Justice]

I agree. If your server has enough hardware behind it you can certainly run
a few VMs on direct attached storage. Plenty of RAM and disk space is
needed. You'll also want as many spindles in your RAID array as possible.

Also, there are many things you'll want to look into and read up on,
however, when using DAS, it will be very important that you have enough
drive space to avoid using dynamically expanding virtual disks.

Have a good one,
Brooke



"Meinolf Weber [MVP-DS]" wrote in message
news:ff16fb662b0d98cbdcb3a7ad2ad9@msnews.microsoft.com...
> Hello cptkirkh,
>
> They will run if the server performance is high enough ofcourse (CPUs and
> RAM), but RAID 5 is not that fast, biggest advantage of RAID 5 is fault
> tolerance, therefore it counts a check sum for each data and stores the
> checksum also to be able to rebuilt a broken disk during each saving step,
> this slows down.
>
> Best regards
>
> Meinolf Weber
> Disclaimer: This posting is provided "AS IS" with no warranties, and
> confers no rights.
> ** Please do NOT email, only reply to Newsgroups
> ** HELP us help YOU!!! http://www.blakjak.demon.co.uk/mul_crss.htm
>
>> I am about to venture off into hyper-v land. I want to start by
>> runnign a consolidated configuration. By this i mean placing about 6
>> VMs on a strong box. These VMs will host only small apps that our
>> company runs. I am not planning on putting exchange or SQL server on
>> here, My server reseller wants me to buy a iscsi box to put the vms
>> on he says it willrun faster. The problem is i am on a budget and
>> can't afford a iscsi box. If i put my host box with RAID 1 for theOS
>> and then RAID 5 for the vm files and being htese are only small app
>> servers will that work or am i crazy? Thnaks for your advice.
>>
>
>