Home | GestaltIT | Enterprise Computing: Has EMC Slipped Zero Block Reclaim Into V-Max?

Enterprise Computing: Has EMC Slipped Zero Block Reclaim Into V-Max?

0 Flares Twitter 0 Facebook 0 Google+ 0 StumbleUpon 0 Buffer 0 LinkedIn 0 0 Flares ×

I spent some time today looking at the release notes for Enginuity code 5874.207.166, which presumably is the one that brings the much lauded Fully Automated Storage Tiering (FAST) into general release on V-Max.  Just above the FAST paragraph I found the following:

Symmetrix Virtual Provisioning Space Reclamation reduces capacity requirements and total cost of ownership by automatically reclaiming chunks (768 KB track groups) that contain all zeros. This is most effective when used on volumes after thick-to-thin migration or replication.

So, it seems that V-Max now supports features previously only seen on 3Par InServ, HDS USP V and HP XP – that is the ability to reclaim empty “zeros” of data from LUNs – otherwise known as Zero Block Reclaim.

I don’t remember EMC mentioning this little fact as part of their big FAST announcement.  In fact, looking back over Barry B’s posts, here’s a link to a post from July in which Barry indicates (quoting again);

I cannot confirm nor deny that VP will support one or more unused space reclamation approaches in the future.

So do EMC just see ongoing space reclamation as a BAU activity, not worthy of an announcement?  I’m surprised that this would be the case.  Reclamation of “empty” storage is incredibly important when migrating from thick->thin storage environments.  Hitachi quote around 40% savings from using ZPR after a migration to thin provisioning on USP V.

Perhaps EMC don’t want us to know that migrating to V-Max can actually reduce the amount of storage in use.  After all, its not good for hardware sales, is it?

By the way, EMC, please feel free to comment on this new feature and how easy it is to use.  I’d be interested to discover how it is implemented.

About Chris M Evans

Chris M Evans has worked in the technology industry since 1987, starting as a systems programmer on the IBM mainframe platform, while retaining an interest in storage. After working abroad, he co-founded an Internet-based music distribution company during the .com era, returning to consultancy in the new millennium. In 2009 Chris co-founded Langton Blue Ltd (www.langtonblue.com), a boutique consultancy firm focused on delivering business benefit through efficient technology deployments. Chris writes a popular blog at http://blog.architecting.it, attends many conferences and invitation-only events and can be found providing regular industry contributions through Twitter (@chrismevans) and other social media outlets.
  • Locutus

    Hi Chris,

  • Locutus

    Hi Chris, IBM’s SVC announcement in October included a new feature called Zero Detect:
    When using Virtual Disk Mirroring to copy from a fully-allocated virtual disk to a space-efficient (thin provisioned) virtual disk, SVC will not copy blocks that are all zeroes
    – Disk space is not allocated for unused space or formatted space that is all zeroes

    Additionally,when processing a write request, SVC will detect if all zeroes are being written and will not allocate disk space for such requests
    – Helps minimize disk space used for space-efficient virtual disks
    – Helps avoid space utilization concerns when formatting vdisks
    – Supported only on Model CF8 storage engines

    So Thin stays Thin.

  • http://basraayman.com Bas Raayman

    Chris, this was indeed part of the new Enginuity. But what is way more important in my opinion, is if they will also provide something like a driver of stack that will actually tell the FS to zero things out and reclaim the space, or if they have gone the 3PAR way and “understand” what the FS does and don’t require any additional installs in the OS. :)

  • http://blogs.cinetica.it Enrico Signoretti

    Chris,
    Compellent has thin import feature too: it doesn’t writes zeros when you import volumes from other storage arrays.
    The feature is very efficient also when you write empty files/blocks ( i.e.: Oracle datafiles).

    In these days i see a little bit of negativity on EMC, ;-)

    ciao,
    Enrico

  • http://thestorageanarchist.com the storage anarchist

    The Enginuity code release you refer to has not yet been formally announced. This week was all about FAST…

  • Paul P

    The bigger picture IMO:

    Is that this is not an important event if you you are so late to the party, I mean, why advertise you came last…? Put it in the draw and when the next customer says they want/need this feature, EMC can pull it out and say they have that tick box as well – “now that you mention it, Mr Customer, yes we have that…”

    But you also need to view this in relation to EMC’s own perceived value of some of these more modern technologies (i.e. specifically those brought to market by others) – in this case, Chuck’s own comments on a related topic, thin provisioning, summarises, I believe, EMC’s position:

    “I think thin provisioning is not-a-good-thing at a philisophical level. It has a role, but I’d recommend using it very carefully, if at all.”

    like many technologies other develop – dont believe thin provisioning is useful and one reason, I believe they use a

    things

  • XIV

    Chris,

    Just to beat a dead horse….IBM XIV incorporates this ability as well. I would say at this point not having the ability is something to talk about apposed to having it, which all enterprise class arrays should have.

    http://www-03.ibm.com/systems/storage/news/press/20091110.html

  • http://thestorageanarchist.com the storage anarchist

    Now that we’ve formally announced the rest of the functionality included in the Enginuity 5874 update that delivered FAST v1 for V-Max, I’ll be happy to discuss Zero Page Reclaim.

    Perhaps best to start with my blog post on the subject: http://bit.ly/784kuT

  • Chris Evans

    I’m guessing you had more to say than hello? :-)

    Chris

  • Chris Evans

    Good point, I should have mentioned SVC too. I was aware, I just forgot. :-(

    Chris

  • Chris Evans

    Hmm, didn’t see that mentioned in the release notes. I assume you’re thinking of the Symantec Thin Reclamation API thing? Or perhaps not and thinking they are doing what Data Robotics do?

    Chris

  • Frank Bohnsack

    As far as I understand it, EMC will implement a functionality into the storage array to understand the FS functionality and thus be able to identify used and unused blocks on a FS level. So zeroing of unused blocks will be as unnecessary as installation of a software component on the server.

    Frank

  • Chris Evans

    Enrico, thanks. Seems more people are doing this than I thought! Still haven’t had chance to get hands-on with Compellent (despite asking). :-(

    Chris

  • http://blogs.cinetica.it Enrico Signoretti

    Compellent has a very good product but their marketing ability doesn’t seem to on par.

  • http://basraayman.com Bas Raayman

    Well, basically that would be my question to them. How do they do that, and yes it was exactly what I was thinking of. :)

  • http://basraayman.com Bas Raayman

    Chris,

    I just checked and you need Enginuity 5874, and more importantly you need Solutions Enabler 7.1.

    With that combination you can use virtual provisioning space reclamation, but there are some drawbacks.

    First of all, it’s not sticky.

    You issue a “symconfigure free tdev type=reclaim” against an entire thin device or use start and end cylinders and off you go. Problem is that you do this once, but after it finishes the reclaim process it won’t check again. If you have something like a thin pool that you use under vSphere for development machines it would be likely that you will see lot’s of changes on your disks, and to make good use of it you will probably want to run it more frequently.

    Secondly, I can only run it against cylinders or thin devices. It would be great for me if I could run it against entire thin pools. Now I need to manually go through all disks or script my process, and with the increasing number of thin devices this is going to cost me more and more time.

    What is good is that I don’t need an agent or a piece of software that will tell my array to punch holes, but it’s just not sticky so it’s a manual job.

    Last point is that you need at least one thin extent, that means one consecutive part of your disk that has zeroes. Standard thin extent size is 12 tracks or 768KB. If part of the extent has data on it, it won’t be reclaimed.

    Hope that helps,
    Bas

  • http://www.compellentblog.com Liem Nguyen

    Hi Chris, Enrico, Compellent actually announced Thin Import with Storage Center Release 4.0 in 2008, and along with it an integrated utility called Free Space Recovery, which reclaims whitespace in Windows environments. (If you’re interested, the announcement is here: http://www.compellent.com/News-and-Events/Press-Releases/2008/Storage-Center4_080219.aspx

    And, yes, I am working on getting Chris a test unit! :)

  • Chris Evans

    Ah, sorry about that. I checked the release note document (dated 18th November) and it was tagged with confidentiality of public. I’m sure I haven’t stolen your thunder….

    Chris

  • Chris Evans

    Thanks Bas

    It’s pretty much like the HDS implementation – although that won’t work with replication (local or remote) in place.

  • Chris Evans

    Frank,

    That’s how Drobo do it. However it’s tricky to make that work when people have used LVMs to combine individual LUNs together. I suspect there will be lots of caveats and restrictions.

    Chris

  • Frank Bohnsack

    Hi Chris,

    yes that’s right, there will be problems when LVMs are used or VMware with VMFS, or … And impressive as it will be that the system will be able to understand Windows, Linux, Solaris, etc. FS it will still be a proprietary solution. I would prefer the extension of the SCSI protocol with commands to tell the storage array that the blocks occupied by deleted files can be released and given back into the free storage pool.

    Frank

0 Flares Twitter 0 Facebook 0 Google+ 0 StumbleUpon 0 Buffer 0 LinkedIn 0 0 Flares ×