Monthly Archives: June 2013

VMware: “adaptive queue depth” setting

What is the recommended LUN queue depth throttling in VMware ESX/ESXi?

According to EMC this “adaptive queue depth” setting is not yet supported (June 2013). The full article can be found on this link. It is known as Primus solution id emc279718.

My advice would be not to use this setting until EMC certifies this setting for use with their arrays.

The exact Article is as follows:

What is the recommended LUN queue depth throttling in VMware ESX/ESXi?
 
  • Need to know QFullThreshold,QFullSampleSize & Queue Fulls values for VMware.
  • Host Connectivity Guide does not include any standard values.
  • Performance issues.
 
OS: VMware ESX / ESXi
Product: CLARiiON / Symmetrix and I assume VNX as well
 
According to Engineering, enabling the adaptive queue depth algorithm is NOT documented in the Host Connectivity Guide or the EMC Support Matrix.
The recommendation is to use the default setting which is disable adaptive queue depth.
Additional checks with E-Lab VMware quality engineers, E-Lab testing is done with the default setting.
 
See emc274169 for additional information and or changes.  Also see these two documents on support pages support.emc.com or Powerlink.Using EMC VNX Storage with VMware VsphereUsing EMC Clariion Storage with Vmware Vsphere & VMware Infracture Version 4.0

ASP Announces Ten Winners for ‘Best Web Support Sites of 2013’

The Association of Support Professionals (ASP) announced this year’s winners of its 16th annual “Ten Best Web Support Sites” competition, a prestigious award that showcases excellence in online service and support.

The 2013 winners include Check Point Software, Cisco Systems, EMC, Intel, Nokia, PTC, and Red Hat and three companies, Ancestry.com, TeamSupport and Tricentis. In addition, Check Point Software was named to the Web Support Hall of Fame, and another world-class support site, Cisco Systems, gained an additional Hall of Fame star.

Read the whole article here: http://bit.ly/17mMtsP

Read more »

Other useful features of USM

Techs focussed on EMC will know “EMC USM” for its use in upgrading storage arrays like Clariion and VNX as well as disk firmwares and installing enablers, but it can be used for other purposes as well.

Gearoid Griffin, a fellow EMC Elect 2013 member, wrote a nice article about it. Go have a look, I find it very interesting!

You can find his article on https://community.emc.com/people/GearoidG/blog/2013/04/04/other-useful-features-of-usm.

EMC Technical Support Links

EMC Velocity Services: Technical Support Links

I just found this page on ECN (EMC Community Network) which helps me a lot finding the right information faster that just using Google.

So this time it’s only a short post, but I hope it helps you find information much quicker.

Here’s the link: https://community.emc.com/docs/DOC-10850

EMC SAN Copy best practices

SAN Copy zoningEMC SAN Copy best practices

  • Just like with MirrorView ports: don’t use SC ports as host front end ports. Try to use dedicated ports for SC
  • Make sure the zoning is correct between the source SAN Copy port and the target SAN Copy port
  • Don’t use zones with multiple storage array (initiator) ports in them. Try to use SIST whenever you can: Single Initiator, Single Target so you’re certain there can only be 1 initiator in each zone

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the community is about helping each other: partition table lost and found

Hardware:

  • 1 Windows 2008R2 server containing 2 HBAs
  • 2 SAN switches
  • EMC VNX-5100
  • 1 LUN presented over 4 paths (2 per HBA)
  • no PowerPath or MPIO, so Windows host sees 4 vdisks and uses only 1 (with the risk of corruption)

Scenario:

After an unexpected reboot the host lost access to the data on the LUN and it seemed as if the vdisk was unformatted or at least corrupted.

  • I checked the VNX, but all 4 paths were available
  • “diskpart” showed the disk, but no volumes, so Windows people thought it was a “SAN issue” (which it wasn’t, of course)
  • I tried enabling MPIO, but by default this host made the LUN (now visible as 1 vdisk instead of 4) read only
  • After disabling MPIO I installed PowerPath (unlicensed) to be sure Windows only sees 1 vdisk instead of 4
  • After the reboot I once again saw 1 vdisk and PowerPath showed 4 paths (of which 2 unlicensed)
  • Still no luck accessing the data

the Community starts here

And here is where it gets interesting. The strength of the community is where you help each other and in this case the customer called me to inform me that since he had nothing to loose anyway he used “TestDisk by CGSecurity” and this tool actually discovers data patterns on disks and in the blink of an eye NTFS was found and the partition could be restored.

No format and restore of an earlier backup was necessary!

2 Free vSphere ebooks on Amazon! On June 5 and 6 2013 only!!

2 Free ebooks @Amazon

Generally I don’t want to abuse a blog to advertise for certain goods, but I’ve found 2 good ebooks for you VMware lovers:

  1. VMware vSphere 4.1 HA and DRS Technical deepdive (http://amzn.to/hwUFhA)
  2. VMware vSphere 5 Clustering Technical Deepdive (http://amzn.to/om16q1)

Make sure you check the Kindle version, since today and tomorrow it will be for $0, so that’s a good deal, don’t you think?