Distributed vs. Simple

dave330i

VMware posted an interesting blog:

Virtualization: Make an informed decision: Distributed vs Simple Architecture - VMware Cloud Management

I've run into distributed vs. simple all the time. Customers and consultants want distributed deployment w/out a valid reason.

Lexluethar

Great read. I agree, most people do not understand the implications of having a distributed vs simple setup. Most people just want distributed because they are obsessed with HA, DR and the 5 nines (99.999%) up time.

What people don't get is the impact of an outage and the user impact. Its surprising, but a lot of vmware admins don't realize that turning off vCenter won't effect anything production. Sure deployment and edits to a certain extent will be effected (IE if you use vDS you can't remove or add servers to that) but servers will continue running.

This goes beyond VMware too, i deal with it on the Windows Server side as well. People wanting DR for every server even though the application isn't HA or HA aware or Cluster Aware.

jabney

i just read this the other good read indeed. Thanks for sharing @dave330i

EANx

Lexluethar wrote: »

Its surprising, but a lot of vmware admins don't realize that turning off vCenter won't effect anything production. Sure deployment and edits to a certain extent will be effected (IE if you use vDS you can't remove or add servers to that) but servers will continue running.

Not quite correct. The VM itself will remain in operation but you can't really manage it. That goes beyond an admin doing management at the vCenter though and includes losing the ability for certain products (like SnapProtect) to take snapshots, etc. I would argue the loss of backup functionality (I don't really consider a snap a backup but that's another argument) does impact operations.

Lexluethar

You can still snap at the exsi level without vcenter running, although most backup software like commvault backup use vcenter as a proxy to snap for backups. You can still edit the vm you just have to do your management functions through the local esxi host and not through vcenter. Where you lose functionality is vcenter specific things like vds, ha, drs, ft, ect.

EANx

My point was that not everything simply continues to run, that your statement that "turning off vCenter won't effect anything production." When the recovery scenario includes training someone on redirecting snaps across a hundred hosts, and certainly is an effect on production.

dave330i

EANx wrote: »

My point was that not everything simply continues to run, that your statement that "turning off vCenter won't effect anything production." When the recovery scenario includes training someone on redirecting snaps across a hundred hosts, and certainly is an effect on production.

Losing vCenter in a vanilla vSphere environment isn't a big deal. If you have a 3rd party backup tool requiring vCenter to be up, that's a separate issue specific to that environment.

techfiend

I'm on the fence whether to implement distributed via mscs or keep it simple and integrated on one windows server. I'm leaning towards the former with cluster across boxes but losing snapshots and relying on OS backups is a concern because it takes a lot longer to restore.

I hope VMware expresses this limitation in the next version. vSphere 6.0 made a lot of improvements with MSCS.

dave330i

techfiend wrote: »

I'm on the fence whether to implement distributed via mscs or keep it simple and integrated on one windows server. I'm leaning towards the former with cluster across boxes but losing snapshots and relying on OS backups is a concern because it takes a lot longer to restore.

I hope VMware expresses this limitation in the next version. vSphere 6.0 made a lot of improvements with MSCS.

Trend in enterprise is to drop MSCS and go SSD.

Lexluethar

6.0 you can use FT and it's supported. That is what I'm hoping to implement when I migrate our envirnoment from 5.5 u2 to 6.0.

I haven't had great luck with mscs as you said it has a lot of limitations within vmware. Until 6.0 vmware hasn't seemed to care much about making vcenter fully ha. Making FT supported in 6.0 was a big step.

techfiend

SSD mean something other than flash?

We use FT which gives good peace of mind against server failure but still leads to vCenter downtime for patching.

6.0 broke out PCS that helps with multiple vcenters which is what I think vmware wants customers to do. Which might play a role in the MSCS limitations. It really can't be that difficult to exclude shared disks from snapshots. Which would make it an obvious choice for HA. I've heard of a lot of mscs issues in 5/5.5 but haven't had an issue in 6.0.

dave330i

All flash storage. One of the enterprise I was supporting did some testing and decided that they'll stop clustering. The only reason they'll deploy a distributed architecture will be for scaling.