Since one of the problems with the newer WD drives is you can't enable TLER on them would the AV series drives be better suited for large RAIDs? Since they claim to be optimized for audio and video playback it would seem a bit more tolerant of errors, preventing the drive drop out issue, the question I guess I have is whether or not the drive reports these errors properly or just returns bad data and how the RAID controllers would handle misreported data...
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WD AV-GP in RAID
- Thread starter -Dragon-
- Start date
The AV drives are optimised for continuous recording, and since skipping a few pixels doesn't really matter, their error correction is fairly lax. They'll return bad data. Unless you're gonna be recording from security cameras, don't bother with them.
The AV drives are optimised for continuous recording, and since skipping a few pixels doesn't really matter, their error correction is fairly lax. They'll return bad data. Unless you're gonna be recording from security cameras, don't bother with them.
This is incorrect. They all have unrecoverable read error rates < 1 in 10^15. That is the same as the best of the non-AV WD green HDDs.
It is possible that they do not go into deep recovery mode, but I cannot say whether that is the case (it is not specified on the spec sheet). If they do not go into deep recovery mode, then they could actually be useful in RAID, as the OP was wondering.
The main difference I can see between the AV-GP models and the non-AV Green models (from the spec sheets) is that the AV-GPs have something WD calls "preemptive wear leveling" that apparently sweeps the head back and forth across the platters periodically.
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This is incorrect. They all have unrecoverable read error rates < 1 in 10^15. That is the same as the best of the non-AV WD green HDDs.
It is possible that they do not go into deep recovery mode, but I cannot say whether that is the case (it is not specified on the spec sheet). If they do not go into deep recovery mode, then they could actually be useful in RAID, as the OP was wondering.
The main difference I can see between the AV-GP models and the non-AV Green models (from the spec sheets) is that the AV-GPs have something WD calls "preemptive wear leveling" that apparently sweeps the head back and forth across the platters periodically.
This is what I meant, rather than the error correction itself. AFAIK, what happens with AV drives is when they are recording and they hit a bad sector, they just skip over it and continue and that piece of data is not written. This provides no benefit to RAID, since there are no redundant copies - the data isn't written in the first place.
This is desirable in the case of a security feed, where one missing byte of data isn't going to be critical (I'm interested to see the behaviour in RAID 1 when this happens). You would not want to store a database, for example, on these drives.
For data storage drives, this kind of behaviour would not be desirable.
Also: why would you need wear levelling on a hard disk?
This is what I meant, rather than the error correction itself. AFAIK, what happens with AV drives is when they are recording and they hit a bad sector, they just skip over it and continue and that piece of data is not written. This provides no benefit to RAID, since there are no redundant copies - the data isn't written in the first place.
That is incorrect. There is no reason for them to not write a sector. The usual HDD behavior of remapping an unwritable sector would be used in that case.