Re: [Xen-users] XCP storage repository using VHD on top of the LVM (FC shared too) instead of the NFS.

[Martinx - ジェームズ <thiagocmartinsc@xxxxxxxxx>]

Hi Burke!

On 25 March 2010 17:31, Vern Burke <vburke@xxxxxxxx> wrote:

"Why they just don't mount a big (1T) local logical volume and
> make the necessary files (storage repo and the VHDs) on the locally
> mounted file system, instead of the remote NFS?"

Because for the cloud to work and allow migration of virtual machines between cloud hosts, all hosts have to be able to access the same storage. You can put the storage on a local drive, you'll just restrict that VM to running on that host only.

Kind of wrecks the idea of the cloud.

Well, I'm gonna change the subject a bit... Lets talk about the thin provisioning outside the scope of the NFS Server...

if you have a fiber channel shared storage LUN exported to two or more XCPs, or even some kind of Cluster LVM, you can use the OCFS2 instead of the ext3, to host the VHD files and being able to do the live motion, etc... So, the same "engine" will manage the VHDs hosted at the NFS server, locally mounted logical volumes with ext3 or SDFS and the FC or CLVM with OCFS2 on top of it...
 

Vern Burke

SwiftWater Telecom
http://www.swiftwatertel.com
ISP/CLEC Engineering Services
Data Center Services
Remote Backup Services

-
 Thiago
 

On 3/25/2010 4:15 PM, Martinx - ジェームズ wrote:

Hi!

On 24 March 2010 18:54, Dave Scott <Dave.Scott@xxxxxxxxxxxxx

<mailto:Dave.Scott@xxxxxxxxxxxxx>> wrote:

   Hi,

   XCP does use VHD format on top of the LVs it creates on iSCSI/FC
   storage. The current problem is that it doesn’t support “thin
   provisioning” (i.e. not pre-allocating). It’s great for making
   snapshots and clones but not so good for space usage… as you observed!

Completely understood...

   There is an early prototype of an XCP/vhd storage daemon which has
   an LVM implementation optimized for being able to quickly resize
   volumes. When that stabilizes, we’ll be able to have thin
   provisioning. We should put the development repo for the prototype
   on xenbits somewhere.

Mmm... You mean this thin provisioning is, in fact, a grow of the
logical volume when it becomes, for example, 95% full?

I'm thinking in a more simple way to do it, looking at the way the XCP
does the mount of the NFS Server and makes its shared repository there,
I think: Why they just don't mount a big (1T) local logical volume and
make the necessary files (storage repo and the VHDs) on the locally
mounted file system, instead of the remote NFS?

Also, we can use the SDFS instead of the ext3 for the logical volume
file system, so we can save more disc space!

I'll try this SDFS this week, to export it through NFS to a XCP node and
sees how fast and secure it is...

Look: http://www.opendedup.org

   Cheers,

   Dave

Cheers!
Thiago

   *From:* xen-users-bounces@xxxxxxxxxxxxxxxxxxx
   <mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx>
   [mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx
   <mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx>] *On Behalf Of
   *Martinx - ?????
   *Sent:* 23 March 2010 20:47
   *To:* Xen List
   *Subject:* [Xen-users] XCP storage repository using VHD on top of
   the LVM (FC shared too) instead of the NFS.

   Hi!

     I thinking why the XCP/XenServer has an option to use the VHD
   format only for the NFS Servers... How to use the VHD on top of a
   local or shared LVM?

     I mean, I want to create a logical volume of 500G and within this
   volume, I'll create the VHDs files instead LVs for each domU.

     And I'll use this setup on top of my FC IBM DS4700 shared storage...

     It is possible?! I want the good of both worlds, the space
   efficient feature of the VHDs (not pre-allocating) with the speed of
   the local or fiber channel storage.

   Thanks!
   Thiago

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