As I’m nearing the date of my 70-689 exam date I see that I haven’t managed to keep up with posts covering my preparation efforts at all (actually find it difficult to allocate time for preparation itself) :). But I decided to post at least something while I’m preparing. Windows client exam emphasizes the way Windows 8.1 (Enterprise) supposed to be used in corporate environments tied together with all the other Microsoft server side technologies. When I did my first Windows client exam it was the same, but server side technology was simpler – there was AD and Exchange of course, but there was no modern day abundance of management and delivery technologies around those. In fact, all that was from non-client side those days in Windows XP exam is basic AD questions, something like how to enable OOF in Outlook (and if you had no acquaintance with Exchange you might had difficulty to find this option in Outlook which appears only when it hooked up to Exchange 🙂 ), and some questions about mass deployment which was by far simpler then (do you remember RIS?).
Now it is different as we have virtualization of multiple blends (server, application, presentation), remote access and device management (including Intune), numerous server technologies incorporated into client OS (client Hyper-V, storage spaces), and things from the cloud (Intune, Office 365). So with increased complexity and multitude of design options in Microsoft enterprise technology stack you have more stuff to learn even when you “touching it” from the client side only.
One of the technologies which come from Windows Server to Windows Client is Storage Spaces and you definitely need to have good idea about what it is and resiliency options it offers. I tried to create basic table for that purpose which you may find below:
Windows Storage Spaces Resiliency Options
|Minimum Disks Required||Can sustain the following number of disk failures||Number of data copies stored||Logical to physical capacity ratio (usable space)||Recommended use case||
Old-school name 🙂
|Simple||1||0||1||1/1||best for temporary data (such as video rendering files), image editor scratch files, and intermediary compiler object files||JBOD or JBOD with RAID0 in case of multiple disks|
|2-way Mirror||2||1||2||1/2||good for storing a broad range of data, from a general-purpose file share to a VHD library||JBOD RAID-1 aka Mirror/JBOD RAID10 (4 disks) aka Stripe + Mirror|
|3-way Mirror||5||2||3||1/3||good for storing a broad range of data, from a general-purpose file share to a VHD library||JBOD RAID1E (odd number of disks) aka striping with mirroring|
|Parity (Single/Dual)||3/7||1/2||1+parity/1 + 2 sets of parity data||2/3||archival data and streaming media, like music and videos
parity space is low write performance compared to that of a simple or mirrored storage space, since existing data and parity information must be read and processed before a new write can occur. Parity spaces are an excellent choice for workloads that are almost exclusively read-based, highly sequential, and require resiliency, or workloads that write data in large sequential append blocks (such as bulk backups)
|JBOD RAID-5 aka striping with parity / double parity RAID aka diagonal-parity RAID, Advanced Data Guarding (RAID_ADG), or RAID-6|
If you not new to Windows tech you saw it before, under different names – now it is revamped and enhanced (on the surface looks dangerously easy to setup and manage 🙂 ). Some low-level terms not needed for Win 8.1 exam but worth your attention: columns, stripes, interleave:
- A stripe represents one pass of data written to a storage space, with data written in multiple stripes (passes).
- Columns correlate to underlying physical disks across which one stripe of data for a storage space is written.
- Interleave represents the amount of data written to a single column per stripe.
If you have difficulty visualizing/understanding parity idea, refer to the following page, which gives good explanation of the way it redistributes data and allows for recoverability:
Here is a picture from aforementioned article which explains RAID5/stripe with parity:
Some links for those who wants to read more on the topic:
TechNet Wiki: Storage Spaces – Designing for PerformanceTechNet Wiki: Storage Spaces Frequently Asked Questions (FAQ)