# Original Bolt - Replacement HD lasted only 7 months WD20SPZX



## dspangenberg (Nov 25, 2001)

I have an original Bolt that came with the 500gb drive. It was a unit that I actually won from Tivo at a contest at CES in 2016! It ran fine until the HD died in June 2018. 

I replaced it with a WD Blue 2TB WD20SPZX. Other than having to hassle with Comcast over replacing and re-paring the cable card, the HD upgrade was pain free and ran perfectly. My ODT temp has varied anywhere from 61° to 64°. 

I started noticing random reboots about 2 weeks ago. Then the interface started to get VERY slow, to the point of being unusable.. 30 second rewind wouldn't work, channel tuning took 10-30 seconds to bring up the new channel, pixelation and pauses. I suspected a HD issue but the new drive has only been in 7 months. I put the Bolt up on some blocks and the temp dropped to ~59° but still had the very same issues.

Last night I took the Bolt cover and hooked up a 2TB 3.5" HGST Enterprise drive with an external power and a long sata cable. It started up fine and I was back and running after going through guided setup. I started all 4 tuners recording and every issue went away. I left the cover off the Bolt and the ODT temp has dropped to ~52°. I guess I will get an external HD housing and stay with a 3.5" drive.

So this morning I started an RMA with Western Digital. I ran their Data LifeGuard diagnostic program and the short test showed everything good, SMART status passed! I am now running the extended test. Is it possible for a HD to pass all the drive tests but still fail in the TIVO? 

BTW I am running software version 20.7.4RC42, so this failure isn't related to the TE4/Hydra and some of the speculation that Tivo is blacklisting some HD's.


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## wxfisch (Dec 27, 2018)

So first, the SPZX drives are not really media drives they are laptop drives, so I would not be super surprised if it did not last as long as a HDD built for AV/NAS use like a Red or an NPVZ Blue. As you alluded to they are not really compatible with TE4 and this may be part of the reason, they just aren't durable enough.

That said, yes, a drive can pass SMART tests and still be bad. In my experience working in IT, SMART is generally pretty useless. It does not predict failures and often does not help in diagnosing a failure. Google has even done studies that show this on the order of thousands of HDDs. My guess would be too many bad sectors causing the drive to seek a lot more while recording/playing back. This would not necessarily be caught by the SMART test but should show in most drive diagnostics programs.


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## DL05 (Jan 6, 2019)

wxfisch said:


> So first, the SPZX drives are not really media drives they are laptop drives, so I would not be super surprised if it did not last as long as a HDD built for AV/NAS use like a Red or an NPVZ Blue. As you alluded to they are not really compatible with TE4 and this may be part of the reason, they just aren't durable enough.
> 
> That said, yes, a drive can pass SMART tests and still be bad. In my experience working in IT, SMART is generally pretty useless. It does not predict failures and often does not help in diagnosing a failure. Google has even done studies that show this on the order of thousands of HDDs. My guess would be too many bad sectors causing the drive to seek a lot more while recording/playing back. This would not necessarily be caught by the SMART test but should show in most drive diagnostics programs.


Exactly what he said. You run a SMART test only for a failure. If it fails the test, the drive is bad. If it passes, you still have to run a full diagnostic to see if it's bad.


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## BobCamp1 (May 15, 2002)

wxfisch said:


> So first, the SPZX drives are not really media drives they are laptop drives, so I would not be super surprised if it did not last as long as a HDD built for AV/NAS use like a Red or an NPVZ Blue. As you alluded to they are not really compatible with TE4 and this may be part of the reason, they just aren't durable enough.
> 
> That said, yes, a drive can pass SMART tests and still be bad. In my experience working in IT, SMART is generally pretty useless. It does not predict failures and often does not help in diagnosing a failure. Google has even done studies that show this on the order of thousands of HDDs. My guess would be too many bad sectors causing the drive to seek a lot more while recording/playing back. This would not necessarily be caught by the SMART test but should show in most drive diagnostics programs.


There's no hardware difference between an AV/NAS drive and a regular drive except for the warranty and the cost. Also, 2.5" drives are no less reliable than 3.5" drives as long as they aren't used in a notebook PC. In fact, they are used all the time in servers.

You are correct in stating that the SMART tests are dumb, and sometimes even a diagnostic test will give a false pass result.


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## wxfisch (Dec 27, 2018)

BobCamp1 said:


> There's no hardware difference between an AV/NAS drive and a regular drive except for the warranty and the cost. Also, 2.5" drives are no less reliable than 3.5" drives as long as they aren't used in a notebook PC. In fact, they are used all the time in servers.
> 
> You are correct in stating that the SMART tests are dumb, and sometimes even a diagnostic test will give a false pass result.


There are a number of differences in different drive types. WD for example uses different firmware on its Blue, Green, and Black drives as well as on its Red and Purple Drives. Its Red drives used to be exclusively filled with helium to reduce wear and help increase spin speeds on the platters and increase platter density due to decreased turbulence (they have started making some filled with normal air though now). There are often differences in the read/write heads, how the heads are parked (or not), how much power the drive uses, the platter speeds, how much cache is included, and on and on.

The 2.5" drives that are used in some servers (not all) are almost exclusively 10k SAS drives, not 5400 SATA drives like you find in a notebook, game console, or TiVo Bolt and are designed to be used in scenarios with battery backed write caching. In general, 2.5" drives usually have worse thermal management. In server use they are placed between the air intake and the fans so they get fresh, cold air coming over them constantly. In an enclosed use like a home console or STB they will often not be cooled as efficiently and thus are more prone to failure. Additionally, to pack 2 or 3TB onto a 2.5" drive, you need to use denser platters and alternative writing techniques like SMR. This increases the price but also increases the chance of failures.

Also, SMART was designed to be a monitoring system, not a failure testing system. SMART HDDs are supposed to alert the host hardware that they are seeing symptoms of failure before the failure happens. It just happened to be that spinning disk drive failures are hard to predict, and so SMART is essentially useless outside of looking at how much use a given drive has seen.


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## V7Goose (May 28, 2005)

BobCamp1 said:


> There's no hardware difference between an AV/NAS drive and a regular drive except for the warranty and the cost. Also, 2.5" drives are no less reliable than 3.5" drives as long as they aren't used in a notebook PC. In fact, they are used all the time in servers.


You are providing misleading information here as far as it pertains to drive use in a TiVo.

The REAL issue is that the WD20SPZX drive uses SMR (shingled) recording, and all anecdotal evidence over that past two years has shown that an SMR drive just DOES NOT LAST LONG in a TiVo. In contrast, the older WD20NPVZ drive uses the more traditional and RELIABLE PMR (perpendicular) recording, and many of us have had no problems at all with that model.

Unfortunately, PMR drives tend to be larger than the same capacity in the crappy SMR technology, and that seems to be why there are almost no reliable drive upgrade options for the ugly Bolt.


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## BobCamp1 (May 15, 2002)

wxfisch said:


> There are a number of differences in different drive types. WD for example uses different firmware on its Blue, Green, and Black drives as well as on its Red and Purple Drives. Its Red drives used to be exclusively filled with helium to reduce wear and help increase spin speeds on the platters and increase platter density due to decreased turbulence (they have started making some filled with normal air though now). There are often differences in the read/write heads, how the heads are parked (or not), how much power the drive uses, the platter speeds, how much cache is included, and on and on.
> 
> The 2.5" drives that are used in some servers (not all) are almost exclusively 10k SAS drives, not 5400 SATA drives like you find in a notebook, game console, or TiVo Bolt and are designed to be used in scenarios with battery backed write caching. In general, 2.5" drives usually have worse thermal management. In server use they are placed between the air intake and the fans so they get fresh, cold air coming over them constantly. In an enclosed use like a home console or STB they will often not be cooled as efficiently and thus are more prone to failure. Additionally, to pack 2 or 3TB onto a 2.5" drive, you need to use denser platters and alternative writing techniques like SMR. This increases the price but also increases the chance of failures.
> 
> Also, SMART was designed to be a monitoring system, not a failure testing system. SMART HDDs are supposed to alert the host hardware that they are seeing symptoms of failure before the failure happens. It just happened to be that spinning disk drive failures are hard to predict, and so SMART is essentially useless outside of looking at how much use a given drive has seen.


I thought we were talking about reliability of the hardware. The firmware is irrelevant, as Tivo does not take advantage of it and it does not increase reliability. Only the 8 GB and higher WD Reds are filled with helium, and that's not for reliability but operability. The differences in heads, power, platters, etc. are true between drives of the same model -- even occasionally the same model number! But there's no general pattern there -- they don't build the Reds to be more reliable that the Blues or Blacks.

2.5" drives tend to be used in mobile and hot environments, subjecting them to unwanted heat and shock. If they're not in that environment, their reliability isn't any less than a 3.5" drive ALL OTHER THINGS BEING EQUAL. (Next time, I'll get my lawyer to read my posts first).

The recording method has a significant impact on reliability. SMR drives will have decreased reliability in a constant write application such as a Tivo. Also, some models are simply less reliable than others, and there's no real pattern there (lawyer added "between similar hard drive designs").


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## wxfisch (Dec 27, 2018)

BobCamp1 said:


> I thought we were talking about reliability of the hardware. The firmware is irrelevant, as Tivo does not take advantage of it and it does not increase reliability. Only the 8 GB and higher WD Reds are filled with helium, and that's not for reliability but operability. The differences in heads, power, platters, etc. are true between drives of the same model -- even occasionally the same model number! But there's no general pattern there -- they don't build the Reds to be more reliable that the Blues or Blacks.
> 
> 2.5" drives tend to be used in mobile and hot environments, subjecting them to unwanted heat and shock. If they're not in that environment, their reliability isn't any less than a 3.5" drive ALL OTHER THINGS BEING EQUAL. (Next time, I'll get my lawyer to read my posts first).
> 
> The recording method has a significant impact on reliability. SMR drives will have decreased reliability in a constant write application such as a Tivo. Also, some models are simply less reliable than others, and there's no real pattern there (lawyer added "between similar hard drive designs").


The firmware is definitely still used, it is how the drive translates the OS level RW commands to the physical action of the head. Firmware also controls things like drive head parking, how often and after what amount of time the platters spin down, and even how the drive writes data to the platters. All these things affect reliability.

All Reds, at one point not that long ago, were filled with He, they are not any more (even some of the 8TB ones no longer are).

Drives of the same Model are functionally identical, using the same head types, same number of platters, same motors and motor orientation, and the same firmware (there are some cases where mid-cycle refreshes are done that will change very minor aspects of these things, but in general this is true).

2.5" drives are often used in mobile only because they are small. They are used in hot environments like data centers only in cases where the cooling is deigned to overcome the increased heat of the environment.

Either way this is all pretty off topic from the initial post. The point is the OP should use the NPVZ WD Blue drive in their Bolt, they are more expensive and harder to find at this point, but they are really the only ones that have been shown to consistently last long times in a Bolt.


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