« NetApp to Acquire Bycast | Main | Poll Results - What is the Size of Your Average & Largest Datastores »

April 08, 2010



Do the NetApp tools work in multi-vendor environments? ie: Can I use the mbrscan and mbralign on both NetApp and Clariion LUNs, even though base chunk size is different?

Vaughn Stewart

@Matt - Yes they do; however, we do not provide support from them when aligning data that does is not accessed thru a NetApp FAS or vSeries controller.


@Vaughn - Thanks. I wasn't sure if aligning was the same for 4K and 64K blocks. I appreciate the info.


I've been aware of this issue for a while -
the real question for the customer is why can't vmware and netapp put their APIs & engineers together (as they have done very successfully in the past) to solve it with zero downtime for VMs?


If I can storage vMotion the live VM to another datastore why can that process not lay down the destination vmdk's in alignment

Vaughn Stewart

Re: [NetApp - The Virtual Storage Guy] www.facebook.com/profile.php?id=658313066 submitted a comment to Raising Awareness Around the Misalignment of Data


Regarding joint engineering efforts to solve this issue... It appears that VMs cannot be aligned without disruption as the GOS cache SCSI blocks into memory and the realignment process results in files residing at an adjusted SCSI address which does not match what may be in the GOS cache.

So today we have a process where one powers down a VM, aligns the VMDK, and restarts the VM. I hope to share some ways to significantly speed up this process.

NetApp VMware engineering are working on a joint solution, but for now, thats all I can share - damn NDAs ;) In the end these efforts will benefit all deployments as this issue impacts every array.

Nick Howell


the link to TR-3747 is broken. You missed the "ht" in "http"

Thanks to you and Duncan for reminding those of us that have aligned to go back and check new systems to be aligned!

Vaughn Stewart

Re: [NetApp - The Virtual Storage Guy] Nick Howell submitted a comment to Raising Awareness Around the Misalignment of Data

@Nick Thanks, correcting now

Scott Howard


Thanks for the post--very helpful. One question regarding this statement:

"First modern GOS types like Windows 7, Vista, 2008 implement GPT versus MBR and as such have a 1MB starting partition offset (versus the traditional 32,256 byte with MBR)."

I see from my win2k8r2 x64 vm that the offset is correct by default on the system volume as you reference above but I also see that the disk is identified as having a "Partition Style" of "Master Boot Record (MBR)" from the Disk Management app in the OS. It wasn't until I cracked open msinfo32 that I confirmed the proper offset and verified your info. Is Disk Mangler misreporting the parition type?



@Vaughn, Can you discuss why rdm's don't need alignment assuming they are properly presented with the appropriate lun type. I find I am asked to explain it quite often because someone will look at a volume within a guest and say "MSINFO32 says the starting offset for this 200 gig E drive is 32,256 so its not aligned"

I get it.. but how do I explain it

Vaughn Stewart

Re: [NetApp - The Virtual Storage Guy] Greg submitted a comment to Raising Awareness Around the Misalignment of Data

@Greg To reset when one uses a RDM they are giving direct access to a LUN by a VM. As such, the LUN type should match the type of the GOS of the VM. When one selects a Windows LUN type, as in your case, the array implements a means underneath the LUN which adjusts where the partition starts on the physical disks without any knowledge or interaction from the GOS.

What results is Windows 2000 2003 servers reporting a starting offset of 32,256 (or the default value) while being aligned on the array.

Does this make sense?


@Vaughn-You mentioned NA is working on some ways to better/faster perform the cluster alignment. We currently have a large amount of VM's that are misaligned; can you expound on when your solution might be ready for release? I'm trying to avoid a very LONG project.


Hi All

Can anyone tell me how to create a misaligned VM on a ESX server.
This would be helpful for my testing.


The comments to this entry are closed.