Bigger Engine Means Better Tires

So you just deployed your new flash array and realize that your hosts aren’t screaming around the track like you were expecting. They’re fast, but they could be faster. Part of the problem is that you just introduced a big fat engine into that old 1980’s Civic frame with balding blades for tires. Sure it’ll work and it will be faster then it was, but you can get so much more out of this setup if you just tweak a few things. EMC published the XtremIO Host Configuration guide for to help with this tuneup. A quick overview of some of these tweaks is included below, but be sure to go consume the entire document for the best mileage and specific thresholds.


  • Balance your hosts across the storage controllers
  • Don’t exceed 16 paths per device
  • Keep your hosts as close to your array as possible and avoid ISL hops

Linux Hosts:

  • Adjust the queue depth for certain HBA’s
  • Adjust your I/O elevators
  • Configure your volumes as multi path with native Linux multipathing or PowerPath
  • Align your block sizes

Windows Hosts:

  • All of the above

Oracle Solaris Hosts

  • All of the above

AIX hosts:

  • All of the above
  • Install EMC AIX ODM

VMware Hosts:

  • All of the above…but also bear in mind that this host may access multiple arrays and settings are global in most cases
  • Adjust the following specific settings
    • Disk.SchedNumReqOutstanding
    • Disk.SchedQuantum
    • Disk.DiskMaxIOSize
  • Adjust the number of concurrent full cloning operations
  • Ensure VAAI is enabled (which it is by default)
  • Leverage Think Provision Eager Zeroed partitions

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