5 Replies Latest reply: Nov 5, 2014 5:12 AM by Brett@S RSS

LUN Migrate on VNX


Hello, I am in the middle of moving around disks/storage pools to assist with balancing performance. A feature to use on the VNX is to just LUN migrate LUNs to the new storage pools so there is no disruption on the host side.


My first question is:

Are there general performance statistics on how long a copy takes for: Low, Medium, High and ASAP?


Next, if I LUN migrate a Thick Pool LUN to a Thin Pool LUN, does LUN migrate copy all zeros to the Thin LUN, thereby making it 100% utilized?


The OS accessing these LUNs is ESXi (5.0), therefore I believe I can also just perform a Storage vMotion.


  • 1. Re: LUN Migrate on VNX

    Doing a LUN migration to a thin LUN will do a zero-block detection and not allocate blocks that only contain zero’s

  • 2. Re: LUN Migrate on VNX
    Christopher Imes

    For information on best practices and theoretical rates for the built-in LUN migration feature, you can refer to the following document:


    EMC Unified Storage Best Practices for Performance and Availability - Common Platform and Block Storage 31.5 — Applied Best Practices.pdf


    Please note this document was superceded (and no longer available directly on support.emc.com); however, the latest document doesn't have the same detail.  You can still use the same estimates, and also the comments made about the feature are still relevant even for the latest version of VNX OE for Block.  Skip to the section: "LUN migration" starting on page 87.  While it provides a section on helping you calculate the duration, it also reminds you it is an estimate and there are several factors to consider:


    1) Maximum number of active sessions

    2) Disk type and RAID configuration (type and number of drives) of source and destination LUNs

    3) Heed the warnings about running ASAP (High is default)

    4) Table 23 and 24 provide estimates for each of the priorities in MB/s

    5) Table 25: Estimating a LUN migration's duration


    Review the comments about "mission critical" workloads, "off-hours", and "busy arrays" which will influence your choices about which priority you choose.  Also keep in mind, you are able to change the priority dynamically which gives you the flexibility to maybe run at medium during active hours and high during off-hours.  Also as you will soon read, ASAP may not be the right choice generally speaking, but you can make that choice after reading what you should find as a very good overview of what to expect with this feature.

  • 3. Re: LUN Migrate on VNX

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  • 4. Re: LUN Migrate on VNX

    Hello guys


    I have one more doubt on LUN Migration  .After the completion of migration Target LUN takes the identity of the Source LUN so how this takeover happen in actual from Source to Target ?

  • 5. Re: LUN Migrate on VNX

    Correct, target assume all aspects of the source, including LUN id, host connectivity etc.


    The cutover is completed automatically by the array, no intervention is required and the original source LUN is destroyed once the migration is completed.