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Ten Things You Need To Know About VSAN

VSAN_EssentialsHere’s the headline: VMware’s Virtual SAN fundamentally changes the way vSphere administrators do storage.  It’s a new world.

While there’s a ton of good material out there, we thought we’d boil things down to the bare essentials for all you busy IT professionals.

Here’s what you need to know:

1. VSAN eliminates the need for an external storage array
VSAN pools flash and/or disks that live in servers to create a single, shared datastore for a cluster.   That means there’s no need for external storage, a storage network or a storage administrator. Although an external array isn’t needed with VSAN, it certainly works well alongside them.  Admins can easily create policies that place workloads on VSAN, external arrays — or easily move them back and forth with Storage vMotion.

2. VSAN is designed for vSphere administrators
Every aspect of VSAN is designed to be a simple as possible for a busy vSphere administrator. For example, there is no “storage console” or plug-in. All the workflows have been seamlessly integrated into vCenter. While this works great for vSphere administrators, it also means that VSAN isn’t designed to be managed by storage administrators — although some certainly do via vCenter.

3. VSAN uses policies to define storage attributes
With VSAN, the vSphere administrator defines policies that include things like protection levels, striping, thin provisioning, etc. and simply refers to an existing policy when provisioning a new VM.

VSAN dynamically carves the requested storage from the single datastore — there is no need to pre-allocate different protection and performance levels as with a typical external storage array.

Every VM (and its VMDK) could potentially have a different policy, if you wanted.  For example, you could have some VMs be able to tolerate one failure, some tolerate two failures, and some that can’t tolerate any failure — all intermixed in the same data store.

Even better, when you change a given policy, VSAN automatically makes the changes on the back end.  This approach is much simpler and less wasteful that the traditional way of doing things.

4. VSAN is designed to be the best storage for your VMs
VSAN doesn’t directly support familiar storage protocols like iSCSI and NFS, simply because it doesn’t need to.

Each VM communicates with VSAN using an internal protocol that’s simpler and faster than a standard storage protocol.

If you might want to expose VSAN capacity externally via iSCSI or NFS, there are good partner solutions available.

5. VSAN can be amazingly fast
Depending on the hardware you run it on, VSAN can deliver surprisingly high levels of performance.  It’s a real eye-opener.  Critical data paths are optimized, and there’s no need to run IOs through an external array’s controller.

The hybrid version of VSAN (mixed flash and disk) can approach the performance of an entry all-flash array for a fraction of the cost.  The all-flash version of VSAN can deliver stupendous performance very cost-effectively.

Performance scales linearly as more servers are added to the cluster.  Individual servers can support multiple disk groups, each of which adds to VSAN’s performance.  More hardware = more capacity and more speed.

Better yet, as server hardware gets faster and cheaper, VSAN gets faster and cheaper as well.

6. VSAN can have very attractive economics
As VSAN runs on standard server hardware, components are very cost-effective to acquire as compared to buying them through a storage vendor.

Be sure to check the VSAN vSphere Compatibility Guide though!

The hybrid version of VSAN for server workloads carries a list price of $2495 per CPU socket.  Horizon users can pay even less.  That means VSAN isn’t priced based on capacity as is the case with most external storage arrays.  The more storage you put behind your cluster, the more cost-effective VSAN can be.

7. VSAN is incredibly robust
Most every time someone tests VSAN, they give the availability features a thorough workout.  They fail drives, controllers, servers, networks — the works! That’s great — but they discover what we already knew — VSAN has a very resilient design.

The new HealthCheck plugin also gives administrators a quick view of their VSAN hardware and network — in addition to making sure an unsupported driver hasn’t inadvertently slipped in.

Even when disaster strikes — a total network partition, or a power fail — it’s designed to never lose data.  And don’t let any array vendor try and tell you otherwise

8.  VSAN is dead simple — really
While some people enjoy getting really deep into VSAN’s functionality, most folks have other things to do.

Our users tell us that they love that VSAN doesn’t demand their attention all the time.   “Set and forget” gets mentioned a lot.

The best part?

There’s no need to learn about storage arrays, or be a storage expert.

9. VSAN upgrades are easy
Need more capacity or performance?  Just add more hardware to your existing cluster.

Moving to a new cluster?  Take your licenses with you.

Software updates are easy as well.  Since VSAN is part of vSphere, upgrades work the same way.

10. VSAN and Horizon are a match made in heaven
While VSAN does well on all sorts of datacenter workloads, when paired with Horizon an extra layer of goodness emerges.

In addition to VSAN’s clear performance and cost advantages, VSAN understands Horizon’s desktop pools and configures itself appropriately.  There’s no need to go back and forth with the storage team — the Horizon administrator is completely in control of the environment.

If you’re using linked clones, capacity requirements are so modest that all-flash becomes very attractive.  If your desktops aren’t persistent, you can consider using a failures-to-tolerate setting of zero, which makes VSAN even more cost-effective.

Compared to an external array, the differences are night and day.

Want To Know More?

Our VSAN Hands-on Lab (HoL) can give you a great feel for the product quickly and easily.

If you’d like to look at hardware configurations, check out our list of pre-certified VSAN ReadyNodes.

To find out where VSAN would fit in your environment, sign up for a VSAN Assessment.

And if you’d like to do a TCO calculation for your environment, check out this nifty tool.

The rest of our handy resources can be found right here.

via: vmware blog

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