A Quick Review of VPLEX Storage Objects

Now that I’ve managed to get my VPLEX clusters up and running, I’m ready to start providing some posts on VPLEX and how it’s configured and used. To get things started, I want to first provide an overview of VPLEX storage objects and how they relate to each other.

Storage volumes: Storage volumes are the LUNs that are presented to the VPLEX back-end ports from the storage array. The screenshot below, taken from the VPLEX management GUI, shows a series of storage volumes taken from two separate back-end arrays.

Extents: Extents are created on storage volumes. You have the option of creating multiple extents on a single storage volume, but EMC generally recommends creating one extent per storage volume. (Future posts will discuss why this is beneficial.)

Devices: Devices are created from extents. You can combine multiple extents together to form a single device, or you can present a single extent up as a single device. As you can see in the screenshot, devices also have a geometry associated with them, like RAID-0 (no mirroring of devices together), RAID-1 (mirroring of devices), or RAID-C (concatenating devices).

Distributed devices: Distributed devices are mirrored devices that are spread across two VPLEX clusters connected together into a metro-plex. Distributed devices require extents from both VPLEX clusters in the metro-plex. Like “regular” devices, distributed devices also have a geometry. As far as I know, all distributed devices will automatically have a RAID-1 geometry. Note that because distributed devices aren’t confined to a single cluster, they reside in a different place in the hierarchy.

Virtual volume: Virtual volumes are built from devices. When a virtual volume is built from a device, it’s referred to just as a virtual volume. When the virtual volume is built from a distributed device, it’s referred to as a distributed virtual volume. Virtual volumes are what are exposed (exported in VPLEX parlance) to hosts via the VPLEX front-end ports.

In future VPLEX posts, I’ll provide information on managing these various storage objects (creating, renaming, and deleting objects) as well as information on integrating VPLEX with other data protection solutions. Stay tuned!

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  1. Yuri Semenikhin’s avatar

    Hi Scott, maybe this question is not must be hire, but i have some question regarding V-PLEX replication,i when we have two storage, one per site and we use V-PLEX as i understand V-PLEX tekes LUN from back-end storages and replication them be twin V-PLEX Cluster, or Storage making replication for example using MirrorView, if storage i didn’t understand that, because when storage make replication target LUN always locked, is it right ?

  2. slowe’s avatar

    Yuri, when using distributed virtual volumes VPLEX uses its own data synchronization mechanism to keep the data in sync between the two clusters. It does not leverage other replication mechanisms such as RecoverPoint, MirrorView, or SRDF, which—as you point out—would leave the target LUN locked and read-only. In this case, VPLEX manages the data synchronization and ensures that both sides have read/write access to the distributed virtual volume.

    I have more VPLEX posts coming—stay tuned!

  3. Yuri Semenikhin’s avatar

    first about V-PLEX i heard from you on VMworld 2010 Europe you and i playing with V-PLEX lab, unfortinatly it was only Virtual Alliance:) ,So Scott if V-PLEX use its own data replication, we can connect any storage model and vendor, i means on DC1 we can use HP EVA and on DC2 we can use EMC CX4, right ?

    P.S this is my blogpost about V-PLEX http://vmlab.ge/vmware-stretched-cluster-v-plex/

  4. slowe’s avatar

    Yuri, you can use both EMC and non-EMC arrays behind VPLEX, as long as they are supported by VPLEX.

  5. dan libonati’s avatar

    Scott…I have some questions here. First I get that the vPlex is the front end engine to “virtualize” storage that is being presented by back end arrays (including non – EMC based arrays), however that all the vPlex is doing. It does not have FAST for “tiering” the data that passes thru it ….Correct?

    It can be used to migrate from Array A to Array B without an outage to the host?
    But does the vPlex have “internal storage” to support a host if there are no arrays backing ending the vPlex? (Configuration would be a vPlex SE supporting or licensed for 20TB).
    Also can you comment as to why the licensing is in one year increments …can a customer buy the solution outright?
    Thanks in advance for your thought here….

  6. slowe’s avatar

    Dan, good to hear from you. VPLEX is an inline storage federation (or storage virtualization, if you prefer) solution. While VPLEX currently does not offer functionality like snapshots, cloning, tiering, etc., within its own feature set, VPLEX does support and honor these features when provided by the back-end array.

    VPLEX can be used to migrate from array to array without downtime. The only downtime *might* (depending upon the situation) be incurred when first introducing VPLEX, since you have to re-zone the SAN to point your hosts to the VPLEX instead of to the back-end storage array.

    As for licensing, I can’t comment—that’s not my thing. Ask me technical questions all day long, but when it comes to licensing and sales I’ll defer you to other, more qualified individuals. Thanks!

  7. Raj’s avatar


    Vplex is the replacement of EMC invista.Vplex is like IBM SVC product.
    Vplex architecture also look like IBM SVC.

  8. slowe’s avatar

    Raj, I wouldn’t go so far as to say that VPLEX is the replacement for Invista. VPLEX and Invista use different architectures and different technologies. And while VPLEX is in-band like IBM SVC, VPLEX’s scale-out cluster architecture is—as far as I know—very different from SVC’s architecture.

    Thanks for your comment!

  9. raj’s avatar


    Flop of Invista takes the EMC to inband like IBM SVC.IBM SVC also support Scaleout upto 4 pairs.Still IBM SVC good for Copy services (Snapshot,mirroring).Thin provisioning and Snapshot nothing difference in Vplex with Invista.Vplex lack of more Heterogeneous Storage Support like SVC and also requires one EMC array as backed for quorum disks.

    But as of my knowledge SVC is best choice for data centerSAN virtualization . because its already completed 6 successful releases. Vplex still needs to get matured to compete with SVC.

    Thanks for your comment!

  10. slowe’s avatar

    Raj, I don’t know enough about SVC to counter any of your claims. I will only point out one factual inaccuracy in your description of VPLEX—it does NOT require an EMC array behind the VPLEX for a “quorum disk”. Any supported array can be used behind the VPLEX.


  11. raj’s avatar

    On readers behalf, I demanding more posts on EMC VPLEX and Vmware VAAI

    Thanks for your comment!!

  12. Seyfullah’s avatar

    Hi Slowe,
    Does VPLEX support multiple sites ? For example 3 sites ?
    Can we use vmware SRM solutions for 3 sites with VPLEX ?

  13. slowe’s avatar

    Seyfullah, VPLEX is currently a two-site solution. You can use it in conjunction with a standard replication solution such as RecoverPoint to build a three-site solution; this is something I describe here:


    No SRM integration or support exists for VPLEX today. This is, IMHO, a major hole and I’ve provided that feedback to the VPLEX product management team. In the meantime, though, you can either build your own scripted solution or manually failover to the second site should a qualifying DR event occur.

  14. chris’s avatar

    have u found a way to automate breaking the mirrors..? or any scripts or tricks that can possibly help..?

  15. Utpal Bhatt’s avatar

    It will be really really beneficial if you can provide an overview (same as you have given for VPLEX) for -

    HITACHI storage enclosures
    EMC Symmetrix storage enclosures
    IBM XIV storage enclosures
    NetApp storage enclosures
    EMC CLARiiON storage enclosures
    HP EVA storage enclosures
    IBM System Storage DS enclosures
    EMC Celerra storage enclosures
    EMC VNX storage enclosures
    3PAR storage enclosures

    Your writing is extremely good.
    I have not seen this on ANY OTHER PLACE as a matter of fact….

  16. lingaraj’s avatar

    Scott, I admire your writing , could you please enlight on,l use of storage objects like extents, devices, logging volumes, virtual disk in achieving the storgae virtualisation
    thanks for your wonderful blog.

  17. KULDIP SINIGH’s avatar

    dear team,

    could you please confirm if we can have full admin guide for vplex in GUI. I tried to find it out on net but no luck.

    need your support at earliest.


    kuldip singh

  18. Sumit’s avatar


    Is it possible to create a distributed volume where both devices already contain data (i.e. cloned devices)?

    Or creating a distributed virtual volume can be achieved only by preserving data with only 1 device i.e. other device should be free LUN?


  19. kishore’s avatar

    Hi Scott,

    what is the importance/necessity to create virtual volumes from devices?
    Can’t we directly present devices to hosts?


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