Category Archives: Windows 8

Is a SAN Better, Cheaper, and More Secure Than Office 365?

SAN’s – especially SAN’s from market leader EMC – are always under attack from companies wishing to cash in on a piece of the rising data growth across all industries and market segments.

  • Some say DAS is best.
  • Some say keep the storage in the servers.
  • Some say you should build your own shared array.

But when it comes to Microsoft environments, it often helps to have independent experts investigate the matter to get a fresh perspective.

In a recent study, Wikibon determined that a shared storage infrastructure (powered by EMC’s next generation VNX2 storage systems) can match the prices offered by Office 365 public cloud and offer more capabilities, more security, and more control.

This, however, assumes a completely consolidated approach for deploying multiple mixed workloads such as Exchange, SharePoint, SQL Server, Lync – where the VNX2 really shines.   We use FAST VP, FAST Cache, and a combination of drive types to achieve the best balance of performance and cost.

Are you looking for more information about deploying Microsoft applications on VNX?    Definitely check here for the most recent best practices guides!

Also check out my recent webinar I did with James Baldwin who leads our Proven Solutions EMC/Microsoft engineering team.  We had a lot of fun doing this one, hope you enjoy it.


Getting Inside the Microsoft/EMC Partnership

A great way to stay in touch with what’s happening in the Microsoft space is to follow Sam Marraccini as he provides a fun perspective on what happens with EMC and Microsoft.

It’s a significant amount of work for one person to do his day job and produce informative videos on Microsoft infrastructure-related technology. Nice work Sam!

The video above you might find interesting – it’s a great discussion with Sam and John Hayden (a CTO in our Unified Division) that explores Microsoft’s ability to put applications like SQL Server or Hyper-V on top of filesystems based on SMB 2.2

EMC works hand in hand with Microsoft to make sure our storage platforms are compliant with SMB 2.2 for platforms like the VNX and Isilon platforms.

Maximum LUN Size for Windows Servers

(numbers last updated 5/30/13) Sometimes people ask hypothetical questions of EMC’s field TC’s (technical consultants) just to see what we say.

Here’s one example of a hypothetical question that a few of us were discussing internally:

Question: What is the maximum size of a LUN you can present to a Windows server?

Answer: 2TB or 16TB or 256TB or 16 EB (exabytes) depending on what website you read.  🙂exabyte


It’s all about the underlying addressing space of the disk and the filesystem you choose to create the volume that gets presented to the Windows server.

Address Spaces and Phone Numbers

I remember a time I could dial a five digit local phone number as in 5-1212 to reach local people.  As the town grew, it extended to seven digits… 555-1212.  Eventually this turned into a 10 digit string such as (123) 555-1212.  We began using a larger addressing space.

Address Spaces and IP Addresses

A better analogy is IPv6 which, although still in its infancy, is being put into place to provide a significantly larger “address space” for IP addresses.  IPv4 (the current standard) allows 232 addresses. The new address space thus supports 2128 (about 3.4×1038) addresses and could eliminate the need for clunky workarounds like NAT.  A typical IPv6 address looks like 2001:db8:cafe::1, compared to an IPv4 address  You can read more about IPv6 in its Wikipedia entry or in the free book, The Second Internet. You can use IPv6 tunnels if your ISP does not offer IPv6 connectivity yet. Using, you can verify IPv6 connectivity.

Back to the Disks

Master Boot Record (MBR) Disks have 32 bit address spaces.  Both the partition length and partition start address are stored as 32-bit quantities. When the block size is 512 bytes (one sector in most cases), this implies that neither the maximum size of a partition nor the maximum start address (both in bytes) can exceed 232 × 512 bytes, or 2 TB.

Alleviating this capacity limitation is one of the prime motivations for the development of the GUID Partition Table (GPT).

GUID Partition Table (GPT) Disks are 64 bit or 264 × 512 bytes giving you much more room to grow. From a Windows persective, Windows Server 2003 SP1 introduced GPT support and has been carried forward since.

Diagram illustrating the layout of the :en:GUI...
Image via Wikipedia

Windows Filesystems Maximums

  • FAT volumes have a maximum size of 4GB and a file size limit of 2GB.
  • FAT32 file systems have a maximum volume size of 32GB with a file size limit of 4GB.
  • NTFS volumes can be up to 2TB on an MBR disk and 16 Exabytes (EB) on GPT disks.
  • The maximum size NTFS volume that has been tested by Microsoft is 16 TB.
  • The maximum size of a VHD is 2040 GB (8 GB short of 2 TB).
  • The maximum size of a VHDX is 64 TB.

In reality, there are other considerations when creating huge volumes:

SCSI limitations.  Microsoft Windows operating systems support two different SCSI standards when it comes to reads and writes (Read10/Write10 and Read16/Write16) , and each of this SCSI standards also have different lookup tables if you will.  Read10/Write10 has room for 4 bytes of info (Max 2TB) and Read10/Write10 has room for 8 bytes of info with a max of about 8 zettabytes.

Backup and Restore. How do you do this effectively for such huge volumes?  Not a streaming back I hope.  Hopefully you’d never have to restore this from tape…

So, while this is not an official EMC blog, unofficially I’d recommend no bigger than a 2 TB LUN presented to a Windows server.  Anything more and you should make sure you are checking with your storage vendor to make sure it’s going to work the way you’d want without causing any problems for you down the road…


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