DataCore Software hits major milestone with release of SANsymphony V

January 31, 2011

DataCore Software today released a major new version of it flagship product, SANsymphony V.  This new product includes over 10 years of storage virtualization innovation.  They have completely rewritten the user interface and made the product open and standards based.  This innovative product will open up many virtualization projects because it will prevent storage from being the cost road block to moving a server or desktop virtualization project along.  Customers will have more choice when they put in DataCore’s storage virtualization software to manage their primary storage.

For more information, here is a direct link to the SANsymphony information on DataCore’s website.

http://www.datacore.com/Software/Products/SANsymphony-V.aspx

Here is a video interview of me while I was at DataCore headquarters recently.

http://storagetv.org/datacore/testvideo.php?vidkey=168


High Availability – Where is your weakest link

May 19, 2010

Great blog post from BernieT from Datacore…

High Availability – Where is your weakest link

It surprises me how often I see companies spending money (large amounts) on technology to make their core business applications resilient to infrastructure failure, but fail to build redundancy into all critical infrastructure components.
What is your weakest link?

I find the primary focus for investment is in Server hardware and software, utilizing server virtualization, clustering and image based backup solutions to provide redundancy/recover-ability for business applications. Many area’s are overlooked and ofter become the Achilles’ heel of IT environments.

Let talk about centralized storage;
While many are quick to invest in multiple servers to build redundancy and “spread the risk” in their IT infrastructure they are complacent when it come to placing their critical data (which without, your servers have no use) on a “single box” array. Yes they are highly available with “internal redundancy” but are a single point of failure and are susceptible to outages, planed or unplanned more often that not, caused by “environment” issues such as power, cooling, air quality, water, building.

The next logical focus is “Disaster Recovery” capabilities, however there is a great deal of complexity and cost associated with having to plan, build, and maintain a business continuity plan, it involves applications, data, hardware, communications, key personnel, facilities.

Doesn’t it seem logical that if there was a product or technology available that allows higher levels of storage availability to be achieved at the production site (or sites) it would be remiss not to consider them first before looking at the complexities of IT disaster recovery capabilities?
What if your critical data could exist in two places at once? geographically separated (whether by racks, rooms, building or states), managed as one and provide transparent IO fail-over and fail-back for all of your application servers?

Surely that would be worth considering?

DataCore Software’s core solution architecture is built around this capabilities, it is called “High Availability, synchronous mirroring” and provides the following benefits;

  • physical separation of storage controllers 
  • physical separation of back-end disk systems
  • Automated fail-over and fail-back
  • is transparent to the application servers
  • mirrored cache protection / consistency 
Without data, what good are servers? Separation ensures and protects data.
 
See original post here.

Datacore in the spotlight at Citrix Synergy

May 18, 2010
Citrix TV showcases latest videos from Synergy 2010 on DataCore; Virtualization is 3 Dimensional

Storage Virtualization: A peek at the 3rd dimension

Virtualization projects are 3 dimensional. Server and desktop virtualization software address two of those dimensions. DataCore storage virtualization software comprises the 3rd dimension.

Dan Crowe of DataCore at Synergy 2010 http://www.citrix.com/tv/#videos/2180

Citrix TV talks to Bettye Grant from DataCore about the partnership with Citrix.  http://www.citrix.com/tv/#videos/2153


Update: A major “All Paths Dead (ADP)” storage related issue with vSphere 4 and how to workaround it

December 29, 2009

Great writeup on the ADP bug and the workarounds from the Virtual Geek blog…

http://virtualgeek.typepad.com/virtual_geek/2009/12/an-important-vsphere-4-storage-bug-and-workaround.html

Common behavior:

  1. They want to remove a LUN from a vSphere 4 cluster
  2. They move or Storage vMotion the VMs off the datastore who is being removed (otherwise, the VMs would hard crash if you just yank out the datastore)
  3. After removing the LUN, VMs on OTHER datastores would become unavailable (not crashing, but becoming periodically unavailable on the network)
  4. the ESX logs would show a series of errors starting with “NMP”

Examples of the error messages include:

    “NMP: nmp_DeviceAttemptFailover: Retry world failover device “naa._______________” – failed to issue command due to Not found (APD)”“NMP: nmp_DeviceUpdatePathStates: Activated path “NULL” for NMP device “naa.__________________”.

This is affecting multiple storage vendors (suggesting an ESX-side issue).  You can see the VMTN thread on this here

Here’s what’s happening, and the workaround options:

When a LUN supporting a datastore becomes unavailable, the NMP stack in vSphere 4 attempts failover paths, and if no paths are available, an APD (All Paths Dead) state is assumed for that device (starts a different path state detection routine).   If after that you do a rescan, periodically VMs on that ESX host will lose network connectivity and become non-responsive.  

This is a bug, and a known bug.   

What was commonly happening in these cases was that the customer was changing LUN masking or zoning in the array or in the fabric, removing it from all the ESX hosts before removing the datastore and the LUN in the VI client.   It is notable that this could also be triggered by anything making the LUN inaccessible to the ESX host – intentional, outage, or accidental.

Workaround 1

This workaround falls under “operational excellence”.   The sequence of operations here is important – the issue only occurs if the LUN is removed while the datastore and disk device are expected by the ESX host.   The correct sequence for removing a LUN backing a datastore.

  1. In the vSphere client, vacate the VMs from the datastore being removed (migrate or Storage vMotion)
  2. In the vSphere client, remove the Datastore
  3. In the vSphere client, remove the storage device
  4. Only then, in your array management tool remove the LUN from the host.
  5. In the vSphere client, rescan the bus.

Workaround 2 (only available in ESX/ESXi 4 u1)

This workaround is available only in update 1, and changes what the vmkernel does when it detects this APD state for a storage device, basically just immediately failing to open a datastore volume if the device’s state is APD.  Since it’s an advanced parameter change – I wouldn’t make this change unless instructed by VMware support.

esxcfg-advcfg -s 1 /VMFS3/FailVolumeOpenIfAPD

Again all credit for documenting this go to the Virtual Geek blog….  http://virtualgeek.typepad.com/virtual_geek/2009/12/an-important-vsphere-4-storage-bug-and-workaround.html

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Update 1:

Has VMware fixed the ADP issue?  Maybe, only time will tell.

http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1016291


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