5TB Bolt Drive to 7.68TB SSD Upgrade, Best Approach?

Discussion in 'TiVo Upgrade Center' started by zombiephysicist, Mar 19, 2019.

  1. RegGuheert

    RegGuheert Member

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    First, I would like to say "Thank you" for doing this experiment and for reporting the results, including updates!

    You have chosen to use an enterprise-class SSD in your TiVo and it appears that you are using about 1% of the unit's endurance each month. Endurance ratings for enterprise-class SSDs are different than those for consumer-grade products, and, in fact, they seem to more closely match the operating environment seen inside the Bolt's case. Specifically, the JEDEC SSD standards organization defines the enterprise operating temperature to be 55°C versus 40°C for consumer grade SSDs, as can be seen on page 26 of this presentation by the then-acting chairman of the SSD standards committee. In addition, the enterprise-grade SSDs ratings are made by operating the units 24 hours/day versus 8 hours/day for consumer SSDs. Again, this seems like a good match for the TiVo Bolt. Also, these enterprise-class SSDs have much higher endurance ratings than their consumer-grade counterparts.

    This all seems very good for the idea of using these enterprise-class SSDs in a TiVo, so where is the rub? If there is one (and I'm not sure there is), I would have to say it has to do with how JEDEC defines the end of life of these SSDs. In fact, the failure criteria for enterprise and consumer SSDs are different, as can also be seen on page 26 of that JEDEC presentation. Notably, the end-of-life criterion for data retention for consumer-grade SSDs is one year, but for enterprise-level SSDs it is only three months!

    On page 27 of the presentation they show two tables which include the MODELED number of WEEKS of data retention remaining at the end of life of SSDs. The top table shows remaining data retention for a consumer-grade SSD at the end of its life and the bottom table shows it for an enterprise-grade SSD. The green boxes show the measurement criteria for those two classes of SSDs.

    So, what to make of all of this?

    Here are some of my conclusions based on the data in this presentation:
    - Most importantly, one of the ways that SSDs degrade is in their ability to retain the data which has been written to them.
    - I don't see any information about how long SSDs retain data when new, but it seems that will depend upon the temperature at which the data was written.
    - One of the reasons enterprise-class SSDs have higher endurance ratings is that their end-of-life criterion for data retention is more lax than is the one for consumer-grade SSDs. You can see this by looking at the two tables on page 27 of the presentation: The end-of-life consumer SSD still has 52 weeks of data retention by the enterprise criterion while the end-of-life enterprise SSD only has 10 weeks (2.5 months!) of data retention by the consumer criterion.
    - It seems clear that a KUID recording on an SSD cannot simply be written and left there for the years that the user might expect it to be available. For instance, if we assume a 55-degree operating temperature for the end-of-life enterprise-class SSD, you can see that anything written on such a degraded unit must be reread and rewritten within two weeks or the information will be lost (top right cell in enterprise chart).
    - For a 24-hour-per-day TiVo application (I understand this is NOT what the OP is doing), the temperature of the SSD will be fairly constant. As such, it seems that for the purpose of data retention while operating, cooler temperatures are preferred since storage and write temperatures are the same in that case (see the bottom-left to top-right diagonal cells).

    All this brings up the following questions in my mind:
    - Does the SSD firmware interpolate into a set of these degradation tables while operating to determine how often to reread and rewrite data before it gets lost, based on total data written and temperature? I assume that it would have to. If it only used the temperature information for that purpose, then it would need to rewrite data too frequently, IMO.
    - Does operation of the SSD at high temperature cause it to have more write endurance? According to this source, it does:
    The obvious implication is that it would be best to keep your SSD buttoned up in your Bolt and running hot to improve its endurance. Too bad everything else in the box will suffer!
    - I wonder at what percentage of life the OP's SSD will have a powered-off shelf life of only one year like a consumer-grade unit would have at end of life.
    - Would a consumer-grade SSD have the same (or better?) life as an enterprise-grade SSD in a TiVo application? I ask this because the Micron 5210 series SSD the OP chose uses 4-bits-per-cell technology (it must write and read 16 different charge levels in each cell). This is equivalent to the Samsung QVO series, which is their lowest-grade consumer product. The Samsung 860 EVO series uses 3 bits per cell, meaning that it only has to differentiate between 8 voltage levels while the Samsung 860 PRO uses only 2 bits per cell, or 4 different voltage levels. I would think the Samsung 860 Pro would have both much more endurance AND much better data retention.

    But I wonder if TiVo has already rendered this entire discussion moot by preventing SSDs from being used in Bolts running TE4. Does anyone have an SSD running in a TE4 Bolt? If so, please let us know your experience.

    Thoughts?
     
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  2. RegGuheert

    RegGuheert Member

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    Mar 16, 2019
    Sure enough, I put a 2TB Samsung 860 EVO into my TiVo Bolt OTA and it stuck at "STARTING UP".

    It seemed like it would be a pretty good fit...
     
  3. zombiephysicist

    zombiephysicist Member

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    Wow, great post with a lot of good issues brought up. I won't pretend to be able to answer all your questions, but will make some points that I think are relevant.

    First, my drive is writing a lot more than its 13% capacity would indicate. I put my power savings on the lowest level of power savings, meaning it won't write 6 live streams 24/7, but it will and does save 'suggestions' which means, my drive has been 100% at capacity for quite a while. And deleting suggestions and recording new suggestions, as well as my wish lists. So there is reasonable turnover data wise, on the drive. That said, with only 13% of my TiVo devoted to things I care about, it's likely much more difficult to notice errors that might crop up, more predominately on the 87% of the "suggestions" content.

    Second, I think, for most TiVo users, the powered-off shelf life of an SSD, which is far shorter for most SSDs than magnetic drives, is not too relevant, as the drive will spend it's useful life powered on and working in the TiVo, and at it's end of life, it's contents will be transferred, and the drive will either be junk or get a 2ndary life in another application.

    The QVO is less ideal, I agree, but on the other hand, the enterprise level endurance of the drives seems fine to handle it, so on a bang/buck level, I'm happy with it. Right now, I think the drive has done way way way way better than the 5TB magnetic spinner I used, that had more 'hiccups' at this point in time than this SSD. Which is kind of surprising.

    Also, as we move to 4k over air and 8k streaming, I suspect future recordings will be not in MPEG2 (which frankly isn't that great) and move to H264/265. I think the way higher compression there may be more subject to errors cropping up. Who knows, what it will mean. Not sure what it will all mean.

    The inability to use TE4 is a serious limitation to be sure. I personally dislike TE4, but I'm sure many others will like it. So, this just may not be an option. On the other hand, I think this experiment is up-ending the old wisdom of "you can't use SSDs on a DVR". Also, I did this upgrade for a friend of mine who has a houseful full of folks beating up his TiVo way more than in mine, and his SSD is holding up as well. His is always 100% full and recording probably 5x as intently (since he has 5 more people in his home using it).

    Anyway, thanks for the fun discussion. Lot of cool issues.
     
  4. RegGuheert

    RegGuheert Member

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    Mar 16, 2019
    Perhaps I have misunderstood: I thought that you were saying the drive was reporting that 13% of its rated durability had been used, but it sounds like you are saying that your drive is 13% full. Can you please clarify which one is the case? TIA!

    For reference, the Samsung 860 EVO 1TB in the laptop I am using right now has a write durability rating in TBW (Total Bytes Written) of 600TB. I can see using their Windows utility called Samsung Magician that the TBW for this drive is currently 7.8TB. In other words, I have used 1.3% of the life of the drive. I can also get this same information by reading the S.M.A.R.T information for the drive, but it is reported differently as "Total LBAs Written", currently 16715636385.

    Since it seems you do not actually have that data for your SSD, we could estimate the worst-case numbers for a 6-tuner Bolt. Assuming six HD streams averaging about 2GB/hour, that would equate to about 50GB/day/tuner or 300GB/day. You happen to have the ONE SSD family from Micron which has durability specifications which can best be described as "wonky", but even if I use the ABSOLUTE lowest durability rating of 0.05 DWPD (Drive Writes Per Day) from the datasheet, your drive is warranted to work for five years even if you write 384 GB to it each an every day.

    Based on that, if the tuners are running 24 hours per day, you would eat up about 15 percent of the drive's (absolute minimum specified) life each year. If you only operated the drive about 12 hours per day, you would use no more than about 8% per year.
    That's certainly true...until it isn't. Imagine someone who moves or puts their old TiVo in a seasonal house or cabin. In those cases, it would be nice to have the unit retain its data. Fortunately, the Bolt should be able to reformat the drive in those cases since the firmware is NOT on the drive.
    Except for the fact that I literally CAN'T use SSDs in my TiVo Bolt OTA.
    Likewise! I look forward to future updates from you on your drive.
     
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  5. zombiephysicist

    zombiephysicist Member

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    Sep 22, 2017
    Sorry, yea the 13% is what the TiVo reports as used. Meaning 13% of its capacity is used to store my shows. In reality, 100% of its capacity is holding shows, the other 87% being suggestions. I'm reporting the capacity as a rough and not so great proxy for intensity of use. My friend's TiVo that I upgraded just like mine, it gets used really heavily and is showing 100% full with their shows (they have a large household). It gets used more intensely. So far it's working well for them too, and they chewed threw a couple of spinning hard drives before the SSD. So surprisingly, this SSD is proving more robust than the spinners.

    Thank you very much for the calculation. I made some similar rough calculations and arrived at roughly the same amount. However, since I'm using the power saver settings so the tuners are NOT recording live TV while the TiVo is in sleep mode, it only records my season passes and suggestions, I suspect the drive will last for as long as the TiVo itself... probably past 10 years. I'll likely have some other TiVo or device by then I would suspect.
     
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  6. zombiephysicist

    zombiephysicist Member

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    Sep 22, 2017
    So we’re a year in, 12 months down, and all is well, knock wood. I think based on all the common wisdom of ssds burning out on Dvr applications in months, this is a rousing success. My drive reports 14% usage.

    My friend, for whom I also upgraded to the same ssd, he’s at 100% capacity and beats the snot out of it. His device is working better and more reliably than with the original 3tb spinner which exhibited some problems from his heavy use.

    I’ll keep reporting on wear, perhaps less frequently for a while, but it seems to me, at least with the settings I’m using, and the drive I picked, this is the future, even for dvrs.

    hoping this thread is useful for others down the line.
     
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  7. tommage1

    tommage1 Well-Known Member

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    Remember the 14% usage reported is only the recordings in the now playing list. Whatever is in the recently deleted folder is also usage on the drive but is not included in the reported 14%. After a year you might be running on a full drive yourself. You can tell, when a new recording is made if something gets permanently deleted in the recently deleted folder your drive is full. Most users who have been using their Tivo for a decent amount of time are probably always running on a full drive. Only way they would not be is if they go into the recently deleted folder and manually permanently delete items occasionally.
     
  8. zombiephysicist

    zombiephysicist Member

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    Sep 22, 2017
    I think I mentioned somewhere earlier in the thread that I have TiVo suggestions turned on with thousands of suggestions, so in fact, my drive is actually 100% full (mostly with suggestions that get deleted and re-recorded regularly). So your point is spot on.
     
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  9. tommage1

    tommage1 Well-Known Member

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    That's very good news. Since drive constantly full a great test :) Large size SSDs will come down in price, some day might see 100TB SSD, heck they can fit 1TB on a micro SD card now, maybe more, that was 2019.
     
  10. ncbill

    ncbill Active Member TCF Club

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    I have a plug-in slot caed for my Apple //e that takes SD cards...and one from years ago that takes CF cards.
     
  11. tommage1

    tommage1 Well-Known Member

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    I still have a //e and a C128D I use occasionally. I think there is an SD card adapter for the 128D (or C64/regular 128) also. Have not purchased them yet, maybe one of these days. Some games for the 64/128 took FOREVER to load and when swapping disks, Phantasie 1 and 2 come to mind..................
     
  12. tommage1

    tommage1 Well-Known Member

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    Put it in an external enclosure and run a heater on it? ;)
     
  13. zombiephysicist

    zombiephysicist Member

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    Has heat been an issue in the bolt? I haven't had an issue with my bolt, although I've taken the unusual step of standing my bolt on it's side. It looks a bit like a hockey stick standing up from its handle with the bent part going off in the air like a tree branch.

    I'm not sure what the sources of heat are, but I guess the heat in that configuration would rise into the hockey stick part where the drive is, away from the CPU part of the TiVo. Not sure what the temperature of the drive is. Is there someway to tell somewhere on some info screen in the TiVo?
     
  14. tommage1

    tommage1 Well-Known Member

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    Bolts do run hot compared to other model Tivos. It's not the drive, I use a 3.5 in an external enclosure, you would think the MB temp of the Bolt would drop with that configuration but for me only a degree or two. So most of the heat must come from the board/chips/CPU?
     
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  15. High Technology

    High Technology Member

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    Apr 16, 2006
    Now that they are making WD Red 2.5" SSDs, I am tempted to try one the next time my Bolt+ drive dies. https://www.westerndigital.com/products/internal-drives/wd-red-ssd

    I've been through 2 TiVo returns now (I have 2 devices), and they last about 2 years each. My main one is now about a year old, and the other one was just replaced last week.

    I have no idea if these will work on TE4, but cycling out these spinners in a device design that clearly put form over functionality is really bad.
     
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  16. zombiephysicist

    zombiephysicist Member

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    15months down. at 20%. Knock wood, all seems ok.

    My friend who I did the upgrade for, is still at 100% usage. He beats the snot out of his. All seems ok, better than the original drive ever was. Also around 15months of usage.
     

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