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4 Replies Last post: Mar 29, 2009 11:32 PM by flzx3000c
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Why additional storage componet such as SAN is necessary in VMware view?

Mar 27, 2009 6:10 PM

Click to view flzx3000c's profile Lurker flzx3000c 3 posts since
Mar 15, 2009

As I know, every physical server in which VM is contained has local storage device, such as SATA/IDE etc., image sharing can be realized by VMFS, and then no

expensive SAN is needed, but this solution is not used, why? SAN is not needed in XenDesktop, as I know.

Another problem:

The management function in View Composer has two operations:

recompose image & refresh image

if the VM image is linked clone, the OS image is not a physical one and only a link to parent OS image, if the parent image is not changed, the daughter OS image

is not changed either, do operations of recompose image & refresh image cause any effect in this situation?

Thanks.


Reply Re: Why additional storage componet such as SAN is necessary in VMware view? Mar 28, 2009 6:55 AM
Click to view Christoph Dommermuth's profile Expert Christoph Dommermuth 553 posts since
Jan 16, 2008 VMware
You could use local storage with View but the whole environment isn't flexible then. What happens if your hardware needs a maintanance? In this case you've to shutdown all desktops when using local storage. When using a SAN/NFS you can move the desktops to another hardware via vMotion. Also for the centralized storage SAN isn't the requirement.. NFS and iSCSI work as well and are supported.

Linked Clones:

1.) You have a master image, and a replica imgae on each datastore, which is a full clone of the master.
2.) The linked clones are linked to the replica image, which is read only. When creating such a pool, a source image is created, which is the first linked clone and will be copied in the VM's later
3.) The linked clones use the data from the replica and write the difference in their own delta disk (OS disk)
4.) When using a persistent pool (this is the pooling solution where you've recompose and refresh) then the linekd clone machine also has an additional user data disk
5.) The user profile is redirected to the user data disk
6.) in case of a refresh/recompose the os disk is deleted in the linked clone vm and the original source image is copied into the vm.
7.) The vm starts up again, gets the old user data disk, binds it to the new os disk.







Blog: http://communities.vmware.com/blogs/dommermuth

Reply Re: Why additional storage componet such as SAN is necessary in VMware view? Mar 29, 2009 8:42 PM
in response to: Christoph Dommermuth
Click to view flzx3000c's profile Lurker flzx3000c 3 posts since
Mar 15, 2009
As to using local storage for View, I think if data can be replicated between physical server and maintain data integrity even if one physical server is out of service,

the vMotion is not a problem without SAN, so I think NFS and iSCSI may be better idea.

About Linked Clones, four kinds of image are referred in your answer: master image、replica image in each datastore(LUN ?)、source image in each pool、OS disk in each VM, do you mean OS disk is initially a copy of soure image which is linked to replica image, OS disk and source image both are not full clone of replica image ?

Thanks.
Reply Re: Why additional storage componet such as SAN is necessary in VMware view? Mar 29, 2009 10:23 PM
in response to: flzx3000c
Click to view tom howarth's profile Guru tom howarth 7,299 posts since
Jul 25, 2005 Moderator
As to using local storage for View, I think if data can be replicated between physical server and maintain data integrity even if one physical server is out of service,

The key here is not SAN but Shared Storage, Local Storage could be used when coupled with a Virtual Storage Appliance like LHN, StorageTEC or even the free stroage appliance from Xtravirt or PHD Virtual.


the vMotion is not a problem without SAN, so I think NFS and iSCSI may be better idea.

Don't get hung up about a SAN, in reality it is the incorrect term to use. the docuentation should really say "Shared Strorage"

About Linked Clones, four kinds of image are referred in your answer: master image、replica image in each datastore(LUN ?)、source image in each pool、OS disk in each VM, do you mean OS disk is initially a copy of soure image which is linked to replica image, OS disk and source image both are not full clone of replica image ?

Have a read of my blog on Linked Cloning technology at http://planetvm.net/blog/?p=61

If you found this or any other answer useful please consider the use of the Helpful or correct buttons to award points

Tom Howarth VCP / vExpert
VMware Communities User Moderator
Blog: www.planetvm.net
Contributing author for the upcoming book "VMware Virtual Infrastructure Security: Securing ESX and the Virtual Environment”.

Reply Re: Why additional storage componet such as SAN is necessary in VMware view? Mar 29, 2009 11:32 PM
in response to: tom howarth
Click to view flzx3000c's profile Lurker flzx3000c 3 posts since
Mar 15, 2009
Thanks, I see.
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