Windows Server 8 Storage Enhancements

 

The recently announced Windows Server 8 brings various enhancements and new features. In fact their number is so large, it probably outshines the AD improvements of Server 2000, the storage improvements (DFS and Storage Management) from 2003 R2 and the probably even the improvements from the 2008-generation (Hyper-V, Branch-Office, Direct Access, NAP, etc.) In this article we would like to concentrate on our first experience with the storage manageability only and draw some conclusions from it.

 

We started in a pretty poor man environment with a single tower PC, using one 80GB disk for the system and two more disks (80GB + 150GB) as our lab rats:

 

DISKPART> list disk

Disk ### Status Size Free Dyn Gpt

Disk 0 Online 74 GB 0 B

Disk 1 Online 149 GB 149 GB

Disk 2 Online 74 GB 74 GB

 

The Storage Pools

 

After installing the file services role you will be presented with a new view on the server manager.

The pools menu is checking for attached raw devices which can be DAS or SAN block devices and actually even mounted VHD files: as long as they are not partitioned and formatted they will be listed as "Primordial". (Compare the above Free disk status with the GUI representation PhysicalDisk Capacity).

 

 

Let’s go ahead and create a new pool:

Start the New Storage Pool Wizard

  • Define a pool name and storage subsystem

  • Select all physical disks needed. There they appear as PhysicalDisk1, PhysicalDisk2…

  • Click Next and Commit

When finished you will be surprised to see in diskpart only the volumes not assigned to a pool

 

DISKPART> list disk

Disk ### Status Size Free Dyn Gpt

Disk 0 Online 74 GB 0 B

 

Creating Virtual Disks within the pool:

Under Virtual Disks / Task start New Volume Wizard

  • Select the storage pool

  • Define a virtual disk name

  • At the layout, size and provisioning choose between different RAID modes and, what is most important, between thin and fixed provisioning type. In our case we used thin provisioning and assigned volume size larger than the available physical space. Correction: in the screenshot below initially a Mirrored Layout was chosen but the initialization broke off with an error. Whether it is due to a bug or is a design issue based on our different physical disk sizes was not clear. For the purpose of this article we simply switched to Simple Layout and then could provision the pool without any errors.

 

 

  • Drive letter and file system settings are straight forward steps

  • Data deduplication is also a new feature. Here you can configure age of files for dedupe (default is 30 days) and fine-tune the deduplication schedule

 

 

As soon as you are finished with that you can check the new block device:

 

DISKPART> list disk

Disk ### Status Size Free Dyn Gpt

Disk 0 Online 74 GB 0 B

Disk 3 Online 500 GB 1024 KB *

 

The process of creating pooled volumes is well structured and simple to handle, decreasing management time and providing a very good overview of all the layers involved.

 

Additional storage enhancements

 

Right from the same file services view you have two more management options handy: the shares and iSCSI virtual disks

 

Working with shares

  • Within the Server Manager from File Services / Shares, launch the New Share Wizard to create a network share. Here you have a choice between Basic, Advanced and Server Application shares. The chosen Advanced SMB share allows for additional data management such as quotas, policies, etc.

 

 

  • Share location and name are straight forward; Other Settings is for enabling or disabling access based enumeration.

  • After checking the permissions you will be presented with the new Management Properties. The User Data goes for single user shares, group data is the common type for shared documents between users and Application Data is used generally for applications with concurrent access, such as Hyper-V

 

 

  • In the last steps you can select a quota from a template and then confirm the creation of the new share.

The decision to provide the administrator with a predefined set of share classes (User, Group, etc.) is highly appreciated. We are still missing documentation though: the difference between the SMB Share – Advanced / Application Data and SMB Share – Server Application is not obvious; in both cases the pop-ups are referring to a Hyper-V storage.

 

Working with iSCSI Targets and VHD

One more feature, integrated within the File Services section of the Server Manager is the iSCSI virtual disks management. Here you can create virtual disks as VHD files (not to be confused with the virtual volumes of the storage pool) and assign them LUNs on an iSCSI Target.

  • If you simply select a volume, a new folder named iSCSIVirtualDisk will be created

 

 

  • Virtual disk name and size are obvious, the name will be used as file name, the disk size window does not give you an option to choose between dynamic and fixed disk though – iSCSI virtual disks are always fixed in size, even if created with PowerShell

  • For the Initiator ID you have the options either to find it automatically, select from cache or manually create a new record of the types: IQN, DNS, IP and MAC Address.

 

 

  • After completion the wizard will create a fixed disk of the configured size. If you need to increase its size you can extend it up to the size of the volume on which it is located

Since the VHD is assigned to an iSCSI target it won’t be possible to mount it from Windows Explorer or the Disk Management. If you need such functionality you will first have to detach it from the iSCSI target using the Disable option from the context menu

 

The last improvement of the storage system, we find worth mentioning here is the extended VHD format (VHDX) that supports up to 16TB. This is not a part of the File Services management console, you will have to use the Disk Manager instead and from there create a new virtual disk. Here an example with roughly 16TB:

 

 

After the creation the disk was automatically mounted, and listed under Disk Manager as well as under the Server Manager / File Services / Pools as a primordial device.

 

Conclusion

 

Considering that we touched a relatively narrow slot of technical improvements on Server 8, not even discussing them in the context (such as VHDX in the context of Hyper-V improvements, SMB Shares with High Availability and Storage Pools in hybrid environments) the features are still surprisingly well convincing. The storage pool is a welcomed feature that has to replace the obsolete (and never quite supported, i.e. under Failover Clustering, etc.) Dynamic Disks. The underlying principle reminds us of the Logical Volume Manager under Linux, but with the cutting edge of a simplified GUI management. The file services console in general is very well arranged and knits together different aspects of storage provisioning such as (SMB/CIFS) shares and iSCSI volumes. Whereas the former is well structured and scenario oriented, the latter is missing in our opinion a separate management of the iSCSI Target with an option to bind an arbitrary block device, be it raw physical disk or a VHD created in advance. It is also not clear why the so called iSCSI Virtual Disks can be only of fixed size and why VHD and VHDX created from the Disks Manager cannot be mapped to existing iSCSI Targets. Here we would appreciate further improvements in the Beta version.

Last but not least we cannot share the baseless accusations that with these storage features Microsoft are driving out OEMs from the market. Sound SAN manufacturers are working on a different level and are offering solutions for large and upper middle class companies. For SMB on the other hand there were only few SAN and NAS solutions that rarely offer a life cycle longer than three years or unlimited features. Microsoft OSes were always lacking a full set of storage features and they can now be warmly welcomed.