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How to get >2Tb storage??

Discussion in 'DIRECTV HD DVR/Receiver Discussion' started by trstew, Mar 15, 2012.

  1. Apr 30, 2012 #81 of 212
    TomCat

    TomCat Broadcast Engineer

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    I contend that it never mattered. Mine are all HR20's. None have ever experienced a slowdown due to the drive being full, and the drives have been full often, including since 2007. I have, in the past, often let the drive fill up and never deleted a thing, allowing the "Until Drive is Full" algorithm to handle it. I have one at 7% currently, and it is just as fast as ever.

    Since there is no technical reason why data on a HDD that is not being accessed at the moment would have any affect on the data that is being accessed at the moment, I'm going to have to go out on a limb here and say that the idea of a HDD or DVR slowing down just because the HDD is full, is probably nothing more than superstition. You may have cause and effect, but they are not related, they are simply coincidental. Its a jump to an unproven conclusion. Human nature at work. For me to lend any credibility to the theory, I would have to have the actual mechanism of such a phantom slowdown explained to me. Go for it. I'm always eager to learn something new.

    PCs? Well, that's different. PCs fragment files, DVRs don't. More indexing? Doubtful; that is based on what is in the guide, not what is on the HDD. Larger DB? I don't think so, because even the catalog DB of a 2 TB drive is pretty small and quickly read. My Macs have some 100,000 files and lord knows how many extents B-tree file fragments on the HDD, and that is not slowing things down, from all appearances. The 1000 or so files you might be able to shoehorn into a DVR's 2 TB drive would hardly make a dent, DB-wise.

    If your DVR is slow, point to the usual suspects, and a full HDD isn't one of them. DVRs with empty HDDs also have no or few SLs scheduled. There is one thing that can make a DVR with an empty HDD seem faster, but it is not because the HDD is empty, it is simply coincidental with the fact that there are also no or few SLs on it.

    SLs can slow down DVRs because any new recording request has to be vetted against all of the other ones that have standing reservations, serially, one at a time. Delete all of your SLs and leave your HDD full, and your DVR will be peppier the next time you schedule a recording (all else held equal), especially a repeating recording. There is a method to the madness of limiting the SLs to 50, in that it prevents a slower UI, which gets exponentially slower with the number of SLs.
     
  2. May 1, 2012 #82 of 212
    unixguru

    unixguru Godfather

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    FYI the D* file system is XFS in real-time mode. It's not going to suffer from degradation when it gets near full.
     
  3. May 5, 2012 #83 of 212
    Rich

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    Sigh... Once again, I tried every size HDD available at the time using 20-700s and various enclosures and every HR did the same thing when they got to ~ 30 to 20% Available on the Playlist meter. They bogged down. Whether you want to believe that is up to you, but it happened every time, didn't matter what enclosure or which HDD or what size the HDD was. Haven't got a clue if D* fixed this issue or not and I'm not gonna go thru all that testing again.



    Nothing more than superstition? Really, Tom?


    An unproven conclusion? Really, Tom?

    Once again, I have several HRs with 50 or close to 50 SLs on them and none of my HRs are what you vaguely refer to as "slow".

    Rich
     
  4. May 5, 2012 #84 of 212
    Richierich

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    I Agree as mine Slowed Down as well and when I Deleted Recordings it Speeded Up but I think Directv changed the way the Database was Structured a while back and that no longer applies as far as my DVRs are concerned.

    I was at 8% on one of my HR24-500s and it didn't Slow Down like it did long time ago so I believe Directv corrected the situation thru programming or Database Restructuring. :D
     
  5. May 6, 2012 #85 of 212
    unixguru

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    Now that I have a bit more time...

    The 2TB limitation has nothing to do with XFS. It's the layers below XFS. As others have stated - partition table types, etc.

    ext3 is the most common Linux file system in use - it is not used in D*. XFS was created by SGI (Silicon Graphics) a long time ago; very high-end robust journaled file system. Real-time mode means data blocks are stored in a separate area (slice/partition) of the disk from metadata. All one needs to do to confirm this is look at the instructions for copying D* drives - it's all XFS. I've done a copy so I can confirm it.

    What I meant in the quoted post is that the file system itself is as optimized as you're going to get - it is not directly responsible for any degradation due to fullness.

    There may be degradation depending on the data and usage pattern. It's not because the file system isn't laying out the data efficiently. Think about what a DVR is doing. Writing 2 and reading 1 HD stream simultaneously. The 2 write streams are going to be physical near each other on the drive; the read stream can be coming from anywhere on the drive. If the writes are near the outer edge and the read is near the inner edge then there are going to be many long (head) seeks from one place to the other. Seeks are the WORST physical delay in a drive. It doesn't matter if it's a 1GB drive or a 4TB drive - full sweep seeks are SLOW. Memory is obviously limited in a DVR so there isn't much buffering. Exhaust a read buffer while waiting for a long seek and you get a pause/stutter. So how can an HR34 handle more streams... more buffers/memory!

    Now throw in an occasional recoverable disk error. Buffering is already very slim. "DVR/PVR/AV" drives have firmware with more limited recovery (i.e. spend less time trying to recover).

    More memory is an obvious solution. They design these mass-market price-sensitive things to work correctly most the time at the lowest cost. Memory isn't the only thing constrained - CPU speed, disk size, etc. They don't put a pair of drives with RAID1 in because the reliability isn't worth the manufacturing and energy cost to most customers.
     
  6. May 6, 2012 #86 of 212
    hdtvfan0001

    hdtvfan0001 Well-Known Member

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    Very educational post #85.
     
  7. May 6, 2012 #87 of 212
    P Smith

    P Smith Mr. FixAnything

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    Just small addition to the "ext3 is the most common Linux file system in use - it is not used in D*"
    Per se, as file system - yes, DVR's data organized by SGI XFS layout. But as partitioning scheme it does.
     
  8. May 6, 2012 #88 of 212
    Rich

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    Seems as if they did fix the issue. Since the eSATA function is not "supported", we were not informed. I'm running one 24-500 with a 2TB internal (have no idea which HDDs are in my HRs, completely lost track, but they are all WDs) with ~ 16% Available and 50 SLs and, aside from the GUI issues (still haven't got the new update), it runs fine. I'll check a few of my 20-700s and see what capacity they're at. Later (you know what that means).

    Rich
     
  9. May 6, 2012 #89 of 212
    Richierich

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    So did that fact that I Replaced my Internal Hard Drive with a Faster Hard Drive with More Cache and I did it with an HR24-500 which has a Faster CPU and More RAM equate to me having No Problems of Sluggishness??? :D
     
  10. May 7, 2012 #90 of 212
    unixguru

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    Everything is relative :)

    Faster spin will take less time to read/write a given amount. But that time is almost nothing compared to seek time. Seek time doesn't change with spin speed.

    More drive cache helps as it reduces the number of seeks needed - instead of "going back" for the next chunk of read data it is already in cache. (Combined with the drive pre-reading entire track.)

    Faster CPU doesn't help seeks.

    More memory will only help if the software allocates more to stream buffers - which it probably doesn't.
     
  11. May 8, 2012 #91 of 212
    Sunner73

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    I am trying to determine how to get the extra storage of 2TB for saved HD recordings that I can keep indefinitely, ie, past the life of the HRxx itself. Maybe by using an external hard drive or by swapping and/or copying the existing recordings onto a new hard drive if I were to "own" the DVR.

    Any solutions?
     
  12. May 8, 2012 #92 of 212
    Mike Bertelson

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    Recording are tied the Receiver ID (RID) that it was recorded on. If you remove/disconnect the drive those recordings are not usable any more.

    Mike
     
  13. May 8, 2012 #93 of 212
    P Smith

    P Smith Mr. FixAnything

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    Only PC based capture device like Hauppauge or BlackMagic's cards. And standalone DVD/BR recorders.
     
  14. May 8, 2012 #94 of 212
    Sunner73

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    So...... there is no way to "re-marry" the Hard Drive(s) to another receiver? You would think that somebody would have done that already.

    Please note that I'm only referring to "a" process for achieving extra storage for archiving purposes on a "owned" receiver only, as I'm sure it would be a violation of T.O.S. if it was leased.

    .
     
  15. May 8, 2012 #95 of 212
    Mike Bertelson

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    There is no way to "re-marry" a hard drive to a different DVR. If the RID doesn't match the recordings won't play.

    I understood you were referring to owned DVRs. ;)

    Mike
     
  16. May 8, 2012 #96 of 212
    dpeters11

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    No, there isn't. And as an FYI there is a legitimate way of increasing the space on a leased box, an external drive.
     
  17. May 9, 2012 #97 of 212
    hdtvfan0001

    hdtvfan0001 Well-Known Member

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    Perhaps some day will come where the eSata is married to the accounts instead of the RID. That would address the ages-old issue of being able to archive content...rather than lose it all when there's ahard drive failure. It would also reduce the storage requirements in some cases where things are duplicated on multiple devices simply to have a backup copy for the same hard-drive-failure reason.

    I'm still thinking we'll see it sooner than later. :shrug:
     
  18. May 9, 2012 #98 of 212
    harsh

    harsh Beware the Attack Basset

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    DIRECTV seems pretty resolute with respect to the current setup. I see little reason to think otherwise.
     
  19. May 9, 2012 #99 of 212
    hdtvfan0001

    hdtvfan0001 Well-Known Member

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    Some DirecTV customers (and those who follow the details) might just know a bit more...plenty of things have changed in the past and will continue to evolve in the future.
     
  20. May 9, 2012 #100 of 212
    P Smith

    P Smith Mr. FixAnything

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    While "plenty of things have changed in the past" , the request for account archiving feature stay for years as sore thumb and there is no hope it will change.
     

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