External drive attached to a DVR

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Yousuf Khan

I've been having some problems recently with recording programs to my
DVR. It's got a 500GB external eSATA/USB drive which I put together from
parts. It had been running perfectly for over a year, and started acting
up just a few weeks ago. So I took the external storage and attached it
to my laptop to check its SMART health. I did that about three days ago,
and it came back clean, no errors at all. So I put it back on my DVR and
ran it some more. It still wasn't recording programs. I noticed that the
drive was making some noises occasionally, like it was getting stuck and
then freeing itself. So I took the drive out again and reattached to the
laptop, and all of a sudden SMART was showing over 80 relocated sectors!
In the span of 1 or 2 days, it had gotten a bunch of bad sectors?

The DVR has some kind of proprietary filesystem format. But I'm
surprised it would get flustered by bad sectors, shouldn't the drive
take care of that? How long does it take the drive to reallocate the
reserve sectors when it discovers bad ones?

Yousuf Khan
 
Yousuf Khan said:
I've been having some problems recently with recording programs to my
DVR. It's got a 500GB external eSATA/USB drive which I put together from
parts. It had been running perfectly for over a year, and started acting
up just a few weeks ago. So I took the external storage and attached it
to my laptop to check its SMART health. I did that about three days ago,
and it came back clean, no errors at all. So I put it back on my DVR and
ran it some more. It still wasn't recording programs. I noticed that the
drive was making some noises occasionally, like it was getting stuck and
then freeing itself. So I took the drive out again and reattached to the
laptop, and all of a sudden SMART was showing over 80 relocated sectors!
In the span of 1 or 2 days, it had gotten a bunch of bad sectors?
Click to expand...
The DVR has some kind of proprietary filesystem format. But I'm
surprised it would get flustered by bad sectors, shouldn't the drive
take care of that? How long does it take the drive to reallocate the
reserve sectors when it discovers bad ones?
Click to expand...

If the drive can recover the data in a sector read with errors, it
will allocated immediately. The recovery process may take pretty
long, depending on the drive. I think > 30 sec are a real
possibility.

If the drive cannot recover the data, then the read will return
in an error and the sector will show up as "pending" in the SMART
data. On the next read, the drive will again try to recover
the data. If the sector gets written, and hence the drive has the
data, it will run a short r/w test of the sector and unless it
passes, reallocation will happen immediately.

So, it is quite possible that the PVR gets flustered by a)
failed reads and b) very long read times. The other oprion is
filesystem corruption or some other software issue, that
a PVR can suffer from as well. No idea how to fix that except
to blank the drive.

Arno
 
Yousuf said:
I've been having some problems recently with recording programs to my
DVR. It's got a 500GB external eSATA/USB drive which I put together
from parts. It had been running perfectly for over a year, and
started acting up just a few weeks ago. So I took the external
storage and attached it to my laptop to check its SMART health. I did
that about three days ago, and it came back clean, no errors at all.
So I put it back on my DVR and ran it some more. It still wasn't
recording programs. I noticed that the drive was making some noises
occasionally, like it was getting stuck and then freeing itself. So I
took the drive out again and reattached to the laptop, and all of a
sudden SMART was showing over 80 relocated sectors! In the span of 1 or 2 days, it had gotten a bunch of bad sectors?
Click to expand...
The DVR has some kind of proprietary filesystem format. But I'm surprised it would get flustered by bad sectors,
shouldn't the drive take care of that?
Click to expand...

Yes, but should and does are two quite different things.
How long does it take the drive to reallocate the
reserve sectors when it discovers bad ones?
Click to expand...

It only does that on a write, so you can recover the data manually if you want to.

Presumably at least some of the bads were in the directory structure.
 
I can't believe this, my DVR has eaten another hard disk! This time it
was a 1TB Seagate, rather than a 500GB Hitachi. I bought the Seagate
just 12 days ago to replace the Hitachi. What the hell is this DVR doing
that's so hard on hard drives? The new drive all of a sudden has 312 bad
sectors!

Yousuf Khan
 
Insufficient mains isolation?

Arno


Yousuf Khan said:
I can't believe this, my DVR has eaten another hard disk! This time it
was a 1TB Seagate, rather than a 500GB Hitachi. I bought the Seagate
just 12 days ago to replace the Hitachi. What the hell is this DVR doing
that's so hard on hard drives? The new drive all of a sudden has 312 bad
sectors!
Click to expand...
 
Yousuf said:
I can't believe this, my DVR has eaten another hard disk! This time it
was a 1TB Seagate, rather than a 500GB Hitachi. I bought the Seagate
just 12 days ago to replace the Hitachi. What the hell is this DVR doing that's so hard on hard drives? The new drive
all of a sudden has 312 bad sectors!
Click to expand...

I was going to suggest inadequate cooling, but surely its the winter there ?

You havent got it in an unusually warmed room or location have you ?

If its not that, most likely its the power supply thats killing the
drives or just plain very bad luck. The last in very unlikely tho.
 
I was going to suggest inadequate cooling, but surely its the winter there ?

You havent got it in an unusually warmed room or location have you ?
Click to expand...

No, it's actually quite out in the open, with lots of visible space in
between for ventilation. I also have long ago replaced its enclosure
with a good quality Vantec aluminum one. When I feel the outside of the
case, it doesn't even feel all that warm either.
If its not that, most likely its the power supply thats killing the
drives or just plain very bad luck. The last in very unlikely tho.
Click to expand...

It's too bad that the DVR doesn't support SMART monitoring. The only way
I can monitor its SMART status is by unplugging it from the DVR and
plugging to my laptop. When I do that, the temperature doesn't show as
too high either (less than 30 C), although mind you there is a brief
period of time between moving from DVR to laptop where it's got some
time to cool, but I don't think it's all that much time.

However, when I ran the SMART self-test on it, the number of bad sectors
kept going up. It initially started out at 276 bad sectors, then after a
short self-test, it went upto 312 bad sectors. Then with a long
self-test it went upto 508 bad sectors and counting (I stopped the test).

One advantage of having the drive fail so quickly is that there is
absolutely no doubt its warranty status. The store just simply did a
quick check over and then exchanged it. But all of the programs I had
recorded on it are now gone.

Yousuf Khan
 
Yousuf Khan wrote
Rod Speed wrote
Click to expand...
No, it's actually quite out in the open, with lots of visible space in
between for ventilation. I also have long ago replaced its enclosure
with a good quality Vantec aluminum one. When I feel the outside of the case, it doesn't even feel all that warm
either.
Click to expand...

OK, then most likely its power supply is dying.
It's too bad that the DVR doesn't support SMART monitoring. The only
way I can monitor its SMART status is by unplugging it from the DVR
and plugging to my laptop. When I do that, the temperature doesn't
show as too high either (less than 30 C), although mind you there is
a brief period of time between moving from DVR to laptop where it's
got some time to cool, but I don't think it's all that much time.
Click to expand...

Yeah, the temperature measurement should be close enough.
However, when I ran the SMART self-test on it, the number of bad
sectors kept going up. It initially started out at 276 bad sectors, then after a short self-test, it went upto 312 bad
sectors. Then with a long self-test it went upto 508 bad sectors and counting (I stopped the test).
Click to expand...

Almost certainly the power supply is failing.
One advantage of having the drive fail so quickly is that there is absolutely no doubt its warranty status. The store
just simply did a quick check over and then exchanged it.
Click to expand...

They likely wont the next time it fails tho. They'll decide that the housing is killing the drives.
But all of the programs I had recorded on it are now gone.
Click to expand...

Yeah, its a real pain with a PVR. I've already got something
like 10TB of stuff I havent gotten around to watching, and
aint about to duplicate that to protect against drive failure.

Its getting past a joke anyway, I found I watched **** all off
the backups for the PVR during our summer quiet season
just finished and have started to delete stuff on those drives
that I'll never get around to watching, mostly fiction but also
some classes of doco, particularly the nature stuff.

That 10TB is a number of physical drives so I wouldnt
lose a very big percentage on a single drive failure.
 
Yousuf Khan wrote
Arno wrote
Click to expand...
You mean lack of power-wise, or noisy power-wise? It was connected to a surge suppressor power bar.
Click to expand...

I've never seen a noisy mains do anything like
that, even in very bad industrial environments.

Bet its just a failing power supply with the Vantec.
 
Yousuf Khan wrote

suppressor power bar.

I've never seen a noisy mains do anything like
that, even in very bad industrial environments.

Bet its just a failing power supply with the Vantec.
Click to expand...
It could be a faulty eSATA cable. I have heard of a few problems with cheap
cables and external cases used with Tivo's
 
They likely wont the next time it fails tho. They'll decide that the housing is killing the drives.
Click to expand...

Well, they don't know it's in an external case, I took it out prior to
returning the drive. All they see is the SMART record of 500+ bad sectors.

Another thing I had forgotten was that this 1TB drive was a factory
refurbished drive. I usually have no problems with refurbed goods, as
they are rebuilt at their original factories. They even backed it with a
3 year warranty, so I guess it's a case of where a refurb was actually
as most people thought it would be.

Yousuf Khan
 
GMAN wrote
It could be a faulty eSATA cable.
Click to expand...

That shouldnt produce reallocated sectors.
I have heard of a few problems with cheap cables and external cases used with Tivo's
Click to expand...

eSATA allows for hot swapping, so even a faulty cable shouldnt produce reallocated sectors.

Even a faulty OV line shouldnt.
 
Yousuf Khan wrote
Rod Speed wrote
Click to expand...
Well, they don't know it's in an external case, I took it out prior to returning the drive.
Click to expand...

Sure, but they will just assume its a faulty power supply in the case used
for the drive if they dont assume that you are putting it in an external case.

Either way, they will just assume that its what you are putting it into thats killing the drives.
All they see is the SMART record of 500+ bad sectors.
Click to expand...

Sure, but that can certainly be produced by what the drive
is in, particularly when you have seen it with two different
drive models now, so it cant be just a bad batch of drives etc.
Another thing I had forgotten was that this 1TB drive was a factory refurbished drive. I usually have no problems with
refurbed goods, as they are rebuilt at their original factories.
Click to expand...

Most of them are actually drives where no fault can be found
so they just decide that the problem was user stupidity.

I dont believe anyone bothers to refurb anymore unless its something
very basic like the firmware problem that Seagate has been seeing.

Its a lot cheaper to just have some asian stamp out a new drive on the cookie machine.
They even backed it with a 3 year warranty, so I guess it's a case of where a refurb was actually as most people
thought it would be.
Click to expand...

I think most 'refurbs' do get the standard warranty.
 
You mean lack of power-wise, or noisy power-wise? It was connected to a
surge suppressor power bar.
Click to expand...

I mean leakage of mains potential into the PVR, which
which could cause current spikes to flow into the
HDD on plug-in.

Arno
 
I mean leakage of mains potential into the PVR, which
which could cause current spikes to flow into the
HDD on plug-in.
Click to expand...

You mean through the eSATA cable? That's the only connection point
between the PVR and its external storage drive.

Yousuf Khan
 
Yousuf Khan wrote

Most of them are actually drives where no fault can be found
so they just decide that the problem was user stupidity.
Click to expand...

I've also suspected that to be the case, many times. And in many cases
that's all it really is.
Its a lot cheaper to just have some asian stamp out a new drive on the cookie machine.


I think most 'refurbs' do get the standard warranty.
Click to expand...

Okay, then I'll wait to see how this new drive fairs.

Yousuf Khan
 
You mean through the eSATA cable? That's the only connection point
between the PVR and its external storage drive.
Click to expand...
Yousuf Khan
Click to expand...

Indeed. This is the only way I see for a device to kill
external disks. If the disk interface gets shocked every
time the disk is plugged in or the PVR swotched on, eventually
the protection circuitry will die and then the interface
electronics itself will die.

Arno
 
Arno said:
Indeed. This is the only way I see for a device to kill
external disks. If the disk interface gets shocked every
time the disk is plugged in or the PVR swotched on, eventually
the protection circuitry will die and then the interface
electronics itself will die.
Click to expand...

That still shouldn't produce reallocated sectors on the physical drive.
 
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