[ngw] (OT) GroupWise, VMWare ESXi, ZCM, etc...
Simon.Shilton at acustica.co.uk
Mon Apr 19 20:45:25 UTC 2010
many thanks for the detailed reply, it now makes a huge amount of sense and is a rather nice solution.
thanks for that
>>> On 19 April 2010 at 19:33, in message <A6728EF2-81D0-430C-9581-78E072C3092C at weisberg.net>, Matt Weisberg <matt at weisberg.net> wrote:
The main benefit, at least to me, is that you can mirror the storage between hosts. You are right in that if I just setup using the free version, I'm basically just creating an iSCSI shared disk out of local storage. Anything that supports iSCSI can then mount that disk. So really, that is one use for it. You have a bunch of locally attached storage not being used for anything, you create a virtual iSCSI SAN out of it.
The big benefit to me is mirroring of the volumes BETWEEN the hosts. So say I have two servers, Server1 and Server2 and I setup SvSAN on Server1 and create an iSCSI target using SvSAN and some of the local disk in Server1. The disk is presented as an iSCSI target and I can go ahead and connect to that disk over iSCSI from both Server1 and Server2. So now I have shared storage, but what if Server1 fails, right. Then I lose my storage. This is where mirroring comes in. On Server2, I install SvSAN and setup a mirror plex of the volume in Server2. This volume mirrors the volume in Server1. Both Server1 and Server2 are configured with TWO paths to this volume now. So even if Server1 goes down, Server2 still has complete access to the shared volume since it is mirrored. And if I'm using VMware HA, then Server2 can just startup any VMs that were running on Server1. If I have VMware Fault Tolerance, I don't even lose the state of the VM (think like old NetWare SFT III). I
can also use Vmotion to move the VMs between the servers without taking them down (granted, to get FT and Vmotion costs big bucks, HA is available in Essentials).
So, does that use case help? I do always use dedicated Gb NICs for the mirroring when I do this and with just two servers, you don't even need a switch, you can just plug the servers into one another with a regular cable.
The power of it is freeing the local disks to be used for more than just internal storage by VMware itself. Not every use case will lend itself to this solution. Your first example, I'm assuming, is using Novell Clustering Services. You could use it for that use case, but if the server with the storage went away, then you would lose everything.
Same on use case 2, if you don't mirror the targets between hosts, then if the host with the storage goes down, you lose everything. However, I could see a use for this if you had a box with tons of storage but not enough horsepower (memory, CPU) to run a lot of VMs. I mean really, you'd just using it as an iSCSI SAN then. You can do the same thing with a lot of the lower cost iSCSI devices now to. The lower end devices from Iomega and NetGear are on the VMware HCL now.
On Apr 19, 2010, at 1:41 PM, Simon Shilton wrote:
> I have been having a look at this, and I am struggling to work out the use case scenarios in an SME setup when a vSan like this is a better approach than merely running the VMs off the internal storage. I have come up with the following 2 situations, and wondered if you could comment:
> (1) when using clustering to provide application HA
> there would be two or more VMs setup in a cluster supporting the relevant application(s) and we want the shared vSan storage accessible from all the VMs to facilitate failover of cluster nodes
> (2) multiple ESXi hosts
> we have one ESXi host with a large quantity of internal storage, and one or more other hosts with smaller internal storage. The VMs running on all three hosts can be stored of the single vSan on the first host - enables VMs to be "moved" between hosts
> >>> On 19 April 2010 at 14:50, in message <72B06E07-4C85-4E91-8F74-7EC16BA5FE4C at weisberg.net>, Matt Weisberg <matt at weisberg.net> wrote:
> You have to get it from a partner. I am a partner, you can use mine (as anyone on the list may if they wish): Weisberg09
> You do have to fill out the form and then you'll get an email with the link.
> On Apr 19, 2010, at 9:23 AM, Joe Acquisto wrote:
> > So, how does one get the "free promo key"?????
> > joe a.
> > On Fri, Apr 16, 2010 at 5:19 PM, Matt Weisberg <matt at weisberg.net> wrote:
> >> Actually, you can do it without a physical SAN by using a virtual SAN. I've actually done this for some of my small customers. Using a virtual SAN (I use SvSAN from StorMagic, www.stormagic.com ) . . .
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