# Has your 921 or other DVR been replaced due to hard drive failure?



## jergenf (Mar 31, 2005)

The purpose of this poll is to determine how many 921 versus 
other DVRs encountered hard drive failure(s) that required replacement.
If you have multiple DVRs then combine the results into one tally also
see examples below for alternate methods of voting.

If you have or had a 921 then select a choice from 1-5.
Else if you have or had another Dishnetwork DVR then select a 
choice from 6-10. If you have both a 921 and other DVR then
choose one choice from both 1-5 and 6-10.

1. *921* had *Zero* (I am so lucky. knock on wood)
2. *921* had *One* (Hey, these things happen)
3. *921* had *Two* (What bad luck I have)
4. *921* had *Three* (Somebody DOWN THERE likes me)
5. *921* had *Four* or more. (I am totally cursed, dude)

6. *Other DVR  * had *Zero* (I am so lucky. knock on wood)
7. *Other DVR  * had *One* (Hey, these things happen)
8. *Other DVR  * had *Two * (What bad luck I have)
9. *Other DVR  * had *Three* (Somebody DOWN THERE likes me)
10. *Other DVR  * had *Four* or more. (I am totally cursed, dude)

*Rules:* If you have or had one 921 or another DVR model select 1 choice 
from either 1 thru 5 or 6 thru 10 (depending if it's a 921 or not).

If you have or had multiple 921s or other DVR models you can either
split the choices if they're different or combine into one total.

*See examples for those that have multiple DVRs:*

John has two 921s in which 1 had a drive failure and the other did not.
He may answer both choice 1 and 2 or just choice 2.

Joe has two 921s in which both had one drive failure. Since both had the
same number of failures he should combine the total to 2 failures which
is choice 3.

Bill has a 921 and 522. The 921 had 1 failure while the 522 had not.
He would pick choice 2 and 6.

Dave has a 942 and 522. The 942 had one failure and the 522 had 2 failures.
He can pick 7 and 8 or just total them up to 3 failure which is choice 9.


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## TechnoCat (Sep 4, 2005)

My first 510 died after about six months. Replaced free. But my 942 has been solid, other than occaisionally going insane and needing to be pulled off the juice and reset.


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## Pils (Sep 20, 2004)

Had numerous 5xx's and never a HD problem. 921 died the first month and seems way too common.


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## boylehome (Jul 16, 2004)

So far 1x921 and 1x721 were replaced. The 921 was just under one year old and the 721 was one of the first sold. The replacements are working fine. Gee, I hope that I don't eat my words for the, "fine" mention.


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## Michael P (Oct 27, 2004)

I'm quoting my own posting from another thread:


> >Quote:
> >Originally Posted by jergenf
> >You've had four 921's in how many years?
> >Were they all hard drive failures?
> ...


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## WildBill (Dec 8, 2004)

921 had Zero (I am so lucky. knock on wood) 32 64.00%
921 had One (Hey, these things happen) 12 24.00%
921 had Two (What bad luck I have) 2 4.00%
921 had Three (Somebody DOWN THERE likes me) 0 0%
921 had Four or more. (I am totally cursed, dude) 2 4.00%
Other DVR had Zero (I am so lucky. knock on wood) 11 22.00%
Other DVR had One (Hey, these things happen) 5 10.00%
Other DVR had Two (What bad luck I have) 2 4.00%
Other DVR had Three (Somebody DOWN THERE likes me) 0 0%
Other DVR had Four or more. (I am totally cursed, dude) 2 4.00%
Multiple Choice Poll. Voters: 50. You have already voted on this poll

I don't understand how you are calculating these percentages. For example, 32/48 921 responses should be 66.66%, not 64% and 11/20 "other DVR" responses should 55%, not 22%. In any event, so far it makes the 921 look more reliable (in terms of HD failure) than other DVRs.


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## jergenf (Mar 31, 2005)

WildBill said:


> Multiple Choice Poll. Voters: 50. You have already voted on this poll
> 
> I don't understand how you are calculating these percentages. For example, 32/48 921 responses should be 66.66%, not 64% and 11/20 "other DVR" responses should 55%, not 22%. In any event, so far it makes the 921 look more reliable (in terms of HD failure) than other DVRs.


The software is doing the actual calculations. There may be some inaccuracies because it's really based more on those who respond versus exact number of units. This is because some people with multiple DVRs may combine the total tally while others may be able to split choices as multiple choices are allowed.

The 921s will most likely get more responses because it's a 921 forum and the poll really is based on 921 versus all other DVRs. I wanted to make a poll that evenly spreads choices for all models but these poll threads only allow a max of 10 choices. My first idea was to place the first 5 choices as the number of failures and the last 5 choices for the models of DVRs but then realized there would be no way to determine failures to particular models.


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## Rovingbar (Jan 25, 2005)

WildBill, I think you expect this to be two polls. The percentages are determined by the total number of voters (50 at the time you copied the data). Of those 50 voters, as many as 48 claim to own (or have owned) a 921, and as many as 20 claimed to own another DVR.

It would be easier to interpret the data if there were two polls, but you can still look at this stuff reasonably well.

Some Conclusions:
- About half of the people in this forum have owned or currently own another DVR

- For every 921 owner who had 1 or more HD failures, there were 2 people who had no HD problems. This implies the failure rate is near 33%. Unacceptably high to me.

- For every other DVR owner who had 1 or more HD failures, there was 1 person who had an HD problem. This implies the failure rate is near 50%. This is unbelievably high.

Here is my math

Total 921 Responses: 60. Total Other responses: 29. So 29/60 is about 50%

921 responses with 1 or more failure = 18. 921 responses with 0 failures = 42. So 18/42 is about 2.3 good HD units to bad HD units. Or a failure rate of 18/60 is about 30%

Other responses with 1 or more failure = 13. Other responses with 0 failures = 16. So 13/16 is about 1.2 good HD units to bad HD units. Or a failure rate of 16/29 is about 45%

Enjoy,
Jeff


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## Rovingbar (Jan 25, 2005)

Oh yah, these observations are not statistically valid, but they do show some interesting trends.


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## jergenf (Mar 31, 2005)

Poll summary as of today is:

*921* out of 69 units 22 had drives failures which results to about 32 percent.
For *other DVRs * was even worse out of 34 drives 16 failed which result to about 47 percent failure rate.

Also bare in mind some reported multiple drive fail occurances so in both camps the failure rate is even higher.


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## jergenf (Mar 31, 2005)

This poll demostrates that the failure rate for hard drives in both 921s and other DVRs is extremely high compared to PCs. In some case as high as 50 percent when normally hard drives have less than 1 percent failure rate within the warranty period. There is no known reason for this as these drives are the same type of drives used in common computers.

Comparing DVR drives to common computers:
They're operating in the same temperture as the home PCs.
Running 24 hours should not be a factor because in most company based computers these drives rarely spin down and are not failing nearly as much.
The type of seeks are generally sequencial compared to the more dynamic seeks performed in home and bussiness computers. 
I'm really wondering if these drives are suffering more from software file corruption rather than hardware failures.


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## Rovingbar (Jan 25, 2005)

Good points jergenf... I can think of several reasons why the failure rates appear so high.

1. First is that this is a 'support forum' so the responses are skewed towards folks who have problems. But that alone (IMHO) would not explain the insanely high failure rate.

2. Data streaming is critical for these devices. There have been a few topics on this board discussing the types of drives used in DVRs. Generally a DVR needs a HD optimized for streaming data (both read and write)

3. Many read-write cycles. All media wears down eventually. We record about 10hrs of HD material a week. That means that we fill the entire HD about twice a month. Realistically, some sectors are over-written at least 4-6 times per month. How many cycles does it take to damage the media? Maybe these HDs are just over used.

4. Software optimization or driver optimization. Like you suggest above, maybe file corruption is the issue, and that could be a software issue. Especially if the SW is not able to check the write activity. No error checking seems like an easy way to make SW work better with a drive that isn't optimized for streaming data.

On with the show,
Jeff


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## jergenf (Mar 31, 2005)

For 921s out of *81* units *28* had drives failures which results to about 35 percent failure rate.
For other DVRs was even worse out of *45* drives *22* failed which result to about 48 percent failure rate.

The drive fail occurances are extremely high for all DVRs.


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## Michael P (Oct 27, 2004)

921 #4 just bit the dust Saturday. #5 is on it's way (Yippee). 

Do I hold the record for most 921 replacements?


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## Ron Barry (Dec 10, 2002)

jergenf said:


> This poll demonstrates that the failure rate for hard drives in both 921s and other DVRs is extremely high compared to PCs. In some case as high as 50 percent when normally hard drives have less than 1 percent failure rate within the warranty period. There is no known reason for this as these drives are the same type of drives used in common computers.
> 
> Comparing DVR drives to common computers:
> They're operating in the same temperature as the home PCs.
> ...


I would have to disagree on a few of your conclusions jergen

1) How do you know they are operating in the same temperature as home PCs. In a lot of cases HD DVRs are placed inside Cabinets that may or may not have enough ventilation to handle the additional heat generated.

2) If my understanding is correct, DVR Hard Drives are always been written two because of the buffer and with an HD DVR you have much higher throughput per hour than the average PC user would put on their hard drive. PCs hard drive activity usually is much more sporadic and has for spinning down. Hmmm I am not sure I would make the statement that PCs rarely spin down. maybe if the user is on it all the time but that is normally not the case.

3) Your assumption on the seeks is that when the content is layed down on the hard drive it is down in a sequential manner. Over time, I am not sure if this is the case. It might be that the DVR HD still has to move around the platter like a PC. I personally would not make this assumption.

As to the numbers from the poll, as someone mentioned these polls are good data points, but may or may not depict reality. Couple of points on the poll in general.

1) People that are not having issues will tend not to participate as frequent as people that have had issues. This will skew the number.

2) We are but a small sampling of a large customer base. 60 samples is not enough to get an accurate trend.

What this poll does do is show that people are seeing failures and they do seem premature. Mike's 5 failures is rather interesting. If I got 5 DVRs fail on me, I would start to look to-wards a possible external source contributing to the failure.

I for one don' t think I participated. First time I have seen the poll. I will participate now.. I have had my 921 for just about a year and have not had a failure.

Well that is my 2 cents.


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## jergenf (Mar 31, 2005)

Ron Barry said:


> 1) How do you know they are operating in the same temperature as home PCs. In a lot of cases HD DVRs are placed inside Cabinets that may or may not have enough ventilation to handle the additional heat generated.


That's a valid point I can only speak for myself. I keep mine out in the open and my house is usually freezing as I use very little heat in the winter and lots of air conditioning in the summer. The most important thing according to page 22 of the user manual is to not block the rear airflow of the unit. Hopefully people realize that and are allowing their unit to breathe.


Ron Barry said:


> 2) If my understanding is correct, DVR Hard Drives are always been written two because of the buffer and with an HD DVR you have much higher throughput per hour than the average PC user would put on their hard drive. PCs hard drive activity usually is much more sporadic and has for spinning down. Hmmm I am not sure I would make the statement that PCs rarely spin down. maybe if the user is on it all the time but that is normally not the case.


When in standby mode the linux operating system is making occasional updates. When on, it's always writing to the hard drive (which is actually the pause buffer). On home PCs the hard drive usually remains spinning and some transactions are always occurring. There is a power save mode which can spin down a drive if one chooses to use that option but most stay on as long as the PC is on. Reading/writing to a drive shouldn't wear it down as some may think, they're usually good for millions of hours before mean failure. Business machines are often on 24 by 7 and their drives may be in constant use if they're a web server or database server. Even in these situation drive failures are rather low.


Ron Barry said:


> 3) Your assumption on the seeks is that when the content is layed down on the hard drive it is down in a sequential manner. Over time, I am not sure if this is the case. It might be that the DVR HD still has to move around the platter like a PC. I personally would not make this assumption.


It's true that as files get added and deleted the drive data becomes fragmented. However linux OS has a clever way of file storage that reduces a file from becoming too scattered. Although a defragging utility would increase performance.
Generally I rarely hear the 921 doing random seeks but there are time when I hear some clatter going on. Believe it or not it happens at times when I'm not recording or playing back a program. Maybe its updating the guide or swapping out memory to disk but that's just a guess.


Ron Barry said:


> As to the numbers from the poll, as someone mentioned these polls are good data points, but may or may not depict reality. Couple of points on the poll in general.


True the people in this forum that contribute are most likely experiencing problems and those that are not probably are not participating. Also to get a real representation it would require thousands of people to contribute to these surveys.
All one can get from these polls is feedback from those that have concerns.
Also I usually just keep a poll open for 90 days it would take years of data collection to make a fair assessment but I'm rather impatient and want quick results.


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## Rovingbar (Jan 25, 2005)

Michael P said:



> 921 #4 just bit the dust Saturday. #5 is on it's way (Yippee).
> 
> Do I hold the record for most 921 replacements?


WOW! You must hold the record. In your defense I understand enough about failure rates to say that while the probability of your situation seems impossibly small, there is a real probability that several customers will experience multiple failures. That is an odd reality of statistics. You my friend are the 1 in 100,000 that should buy a lottery ticket! :lol:

After so many failures, surely you have some suspicions on the cause. Can you share them with us? Do you live in a dry or humid environment? Does your 921 run 24/7? Did those gremlins from the 80s come to stay with you?

Inquiring minds want to know and all that...


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## Michael P (Oct 27, 2004)

After losing all my recordings to the ZSR bug (1st unit) I cut back on some timers. I used to do daily recordings of programs that I may or may not get to actually watch - a sort of "on demand" situation. I still had a daily timer on #2 but for only one half-hour program as opposed to that program plus an hour long program. Plus I had several weekly timers. I was able to back up #2's recordings before I packed it up for shipment. #3 must have been damaged in shipping - the hard drive was significantly louder out of the box. I tried to back up to tape but the playback was jerky - it paused by itself.

#4 was different - I had absolutely no warning, it just died! I can hear the fan but it won't boot up. I used the fewest number of timers (no dailys, only one weekly) and never got the chance to back up 

Humidity in my house averages 55% (I have a hygrometer on top of my entertainment center). No other component sits anywhere near the 921. I may try a higher shelf for the next unit.


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## jergenf (Mar 31, 2005)

Michael P said:


> I was able to back up #2's recordings before I packed it up for shipment.


Was the second unit replaced because of a drive failure? You mentioned that you was able to backup your programs before shipping. The problem I had was like your unit #4 with no warning and failed to boot ever again.


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## Michael P (Oct 27, 2004)

#2's problem was it kept losing it's operating system ("ATE not found"). One neat thing about the software on the 921 was that it could actually repair itself. I was treated to a 4 minute light show with all three LED's firing off one at a time form top to bottom (red, blue, amber,...). After 4 minutes the 921 would reboot and the factory defaults would be in place. I also had to rescan the OTA's. Gratefully, the recordings that were made before the "ATE crash" were still intact! I went through 2 "auto-repairs" under 215. Then the unit was stable until I believe 219. I had 2 ATE crashed back-to-back (I was not done resetting my preferences and scanning the OTA's before it crashed again).


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## Rovingbar (Jan 25, 2005)

Man, you ARE the statistical anomaly that blows the curve. It sure seems like each failure was different. I'm serious about the lottery... it couldn't hurt at this point. :lol:


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## Michael P (Oct 27, 2004)

> It sure seems like each failure was different.


 Yes, and no.
#1) "ZSR of death" was considered a hard drive failure, however it was really a software bug that trashes the data.

#2.) "ATE not found" The partition of the hard drive that holds the operating system had errors. The software was able to repair the lost data, however the problem reappeared later and when it reappeared it happened twice back-to-back.

#3.) The hard drive was noisy right out of the box. Started having ATE errors after being in service for only around two weeks. It got so bad that the repair function failed to get the system running. Just before the unsuccessful repair, it would not play back recordings properly, it would stop and go on it's own.

#4.) Worked flawlessly until last Saturday when, with no warning, it just died. It would not power up, would not reboot. When I attempted a power cord reboot I could hear the fan but that was the only sign of life.

I just set-up #5 last night. Wish me luck!


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## jergenf (Mar 31, 2005)

Just wondering if anybody has had a 921 for over a year without a hard drive problem?


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## ntexasdude (Jan 23, 2005)

I've had mine since Jan '04 with no real problems other than an ocassional stuck aspect ratio and a few other very minor hiccups. It continues to work great. I have no daily or weekly timers set and really don't record all that much on it. I rarely turn it off.


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## Ron Barry (Dec 10, 2002)

I am very close to a year without a HDD issue. Knock on wood.


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## jergenf (Mar 31, 2005)

ntexasdude said:


> I've had mine since Jan '04 with no real problems other than an ocassional stuck aspect ratio and a few other very minor hiccups. It continues to work great. I have no daily or weekly timers set and really don't record all that much on it. I rarely turn it off.


Lucky you, nearly two years with your original 921. 

Mine went out (drive fail) after 9 months. I did use it allot, though and rarely shut it off.


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## ntexasdude (Jan 23, 2005)

jergenf, I mistyped, I meant Jan '05 and not '04.

My apologies.


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## lujan (Feb 10, 2004)

jergenf said:


> Just wondering if anybody has had a 921 for over a year without a hard drive problem?


I've had mine since February of 2004 and have not had to replace the hard drive. Approaching 2 years...


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## Ken Green (Oct 6, 2005)

12/14/04 still going....
tick...tick....tick....


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## jergenf (Mar 31, 2005)

*Update: DVR hard drive failures .*

For the *921* *total=115 *there were *39 bad *and *76 good*.

As far as *other DVRs **total=64 *there were *31 bad *and *33 good*.

So failure rate is about *1/3 for 921 *and close to *1/2 for others*.


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## jgerow (Apr 12, 2004)

jergenf said:


> Just wondering if anybody has had a 921 for over a year without a hard drive problem?


Yes, my "post- blue line fix" 921 had been working very well until it died (coincidentally with the L773 download). [Seems the downloader put the new L773 over a bad spot on the disk, so the ensuing reboot would try to load L773 and when it encountered the bad spot, re-try until it gave up and rebooted, ...and rebooted, ...and rebooted .... until I discovered it a day or so later.

Unfortunately the replacement HEED was DOA with a hard disk failure. -- and had the initial greeninsh-blue-gray "HARD DISK FAILED" screen to prove it. Proceeding on, it seemed the tuner was working fine.... but because it had the original factory load on it, the only channel I could get was 101. (No current download means no authorization is possible as well as no current maps, no menus, no OTA. Looks like with "Better TV" I get a choice: 101 with the endless repeats of how to use your remote, or the HARD DICK FAILED error page. Both are rated "PG," and are commercial-free. )

[So as not to bias the poll: I don't think the replacement's failure should be counted, since it didn't really replace my original 921. Replace in location true, but not in service! Let's see how the "replacement"'s replacement does.]


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## ibglowin (Sep 10, 2002)

Ditto that for me.

I have 2 921's actually. First was received in Jan '04, 2nd in Dec '04.

Knock on wood as they say.....



lujan said:


> I've had mine since February of 2004 and have not had to replace the hard drive. Approaching 2 years...


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