Does NAS RAID Storage harm audio quality if a drive needs to be replaced?

[timjones781]

Hi all,

Im thinking of using a NAS RAID storage device for my audio. I want to choose a raid setup that will protect me against drive failure.

 

The most appealing is RAID 5 considering i can take 4 drives, use 3 of them and the 4th is used to for the indexing and rebuilding of the data. However, a simple RAID 10 mirroring system is the safest bet, but i don't get the most out of the RAID system.

 

My confusion is, How can one drive (6TB) successfully rebuild 3 other drives (18TB)? The math doesn't make sense.

 

And if it does recreate the missing data with some type of stored index of data, how will it rebuild the files? It seems like it will most likely affect the sound quality of the files if it has to manually rebuild them and add 1's and 0's

 

Any insight into this would be much appreciated.

[plissken]

Hi all,

Im thinking of using a NAS RAID storage device for my audio. I want to choose a raid setup that will protect me against drive failure.

 

The most appealing is RAID 5 considering i can take 4 drives, use 3 of them and the 4th is used to for the indexing and rebuilding of the data. However, a simple RAID 10 mirroring system is the safest bet, but i don't get the most out of the RAID system.

 

My confusion is, How can one drive (6TB) successfully rebuild 3 other drives (18TB)? The math doesn't make sense.

 

And if it does recreate the missing data with some type of stored index of data, how will it rebuild the files? It seems like it will most likely affect the sound quality of the files if it has to manually rebuild them and add 1's and 0's

 

Any insight into this would be much appreciated.

 

It's parity information that is used to recalculate:

 

2+2+2+2 = 8

 

X+2+2+2 = 8

 

X represents the lost drive. Mathematically the missing two can be restored. In the crude example we would subtract 6 from 8 and get 2.

[timjones781]

Hey Thanks for the info,

 

Any insights into how manually rebuilding files affects sound quality?

 

I've never experienced any issues with files being copied from one drive to another, but i have noticed degradation in quality when i process a file (example: 24bit 192kHz gets processed using an audio software and then is rendered)

 

curious if RAID rebuild math will have a similar (negative) effect.

[plissken]

Hey Thanks for the info,

 

Any insights into how manually rebuilding files affects sound quality?

 

I've never experienced any issues with files being copied from one drive to another, but i have noticed degradation in quality when i process a file (example: 24bit 192kHz gets processed using an audio software and then is rendered)

 

curious if RAID rebuild math will have a similar (negative) effect.

 

Why worry about an infrequent event? The rebuild will affect read/write performance. Given the low bandwidth requirements of even 24/192 audio, I doubt a difference will be heard over the network.

 

In a home environment you should proactively replace drives ~4-5 years.

[mansr]

In a home environment you should proactively replace drives ~4-5 years.

 

Make that warranty less 6 months.

 

As for SQ impact of a degraded RAID, it has no impact and should be a rare event either way. Nothing to worry about.

[plissken]

Make that warranty less 6 months.

 

As for SQ impact of a degraded RAID, it has no impact and should be a rare event either way. Nothing to worry about.

 

Live dangerously.

[timjones781]

I guess a better way of asking is,

Whether you agree with my opinion of sound quality loss, lets assume we all agree and start there.

 

So if we all agree that rendering files decreases sound quality, will RAID rebuilding hard drives have a similar impact?

[wgscott]

ZFS, for example, uses checksums to guarantee that the files remain bitwise-identical. Assuming that you can not distinguish between files with identical checksums, there will be no degradation, ipso facto.

[timjones781]

ZFS, for example, uses checksums to guarantee that the files remain bitwise-identical. Assuming that you can not distinguish between files with identical checksums, there will be no degradation, ipso facto.

I can here the difference between a FLAC file and a WAV file of the same quality, as well as a WAV file that has been zipped with compression and uncompressed.

 

in both tests the non compressed files sounded better.

 

Does this change your answer?

 

(sorry don't mean to be picky just trying to get opinions on what RAID will do, not necessarily express my findings on sound quality degradation)

[wgscott]

I can here the difference between a FLAC file and a WAV file of the same quality, as well as a WAV file that has been zipped with compression and uncompressed.

 

in both tests the non compressed files sounded better.

 

Does this change your answer?

 

(sorry don't mean to be picky just trying to get opinions on what RAID will do, not necessarily express my findings on sound quality degradation)

 

Well, if you eschew the constraints imposed by physical reality, a whole world of alternative facts having equal merit become manifest. If you believe bit-identical files can sound different based on their processing history, then no amount of evidence to the contrary will ever convince you that the NAS is doing its job correctly. I suppose this is the new political/epistemological reality, and we all need to get used to it. Facts simply no longer matter.

 

Have you considered ripping your digital files to vinyl, so they will retain their initial magical qualities?

[ms012873]

If you do implement RAID in a NAS, you may wish to consider buying NAS level hard drives. While more expensive, they are significantly more durable and long-lasting, especially in a NAS enclosure. hard drives are available in three broad categories--desktop, NAS, and Enterprise. I suggest you avoid desktop level, if your concern is drive failure. Ignore specifications of "mean time between failure," commonly promoted by drive manufacturers and implying a seemingly infinitesimal failure rate, which create the illusion that standard desktop drives are sufficient--they are not. In addition, you may wish to consider purchasing a 6 or 8 bay drive and implementing RAID 6, instead of the RAID 5 configuration you describe. Many articles and discussions on the net describe the differences between RAID 5 and 6, as well as the advantages of building a RAID using the higher quality NAS level drives. Finally, I recommend that you buy an enclosure capable of communication with a battery backup and then be sure to use a battery backup and to implement the battery's shutdown software (which will require connecting the NAS to the battery via a communications cable--usually a USB cable).

 

 

Sent from my iPhone using Computer Audiophile

[plissken]

I can here the difference between a FLAC file and a WAV file of the same quality, as well as a WAV file that has been zipped with compression and uncompressed.

 

in both tests the non compressed files sounded better.

 

Does this change your answer?

 

(sorry don't mean to be picky just trying to get opinions on what RAID will do, not necessarily express my findings on sound quality degradation)

 

Alex?(!)

[wgscott]

Alex?(!)

 

Conway.

[jabbr]

I can here the difference between a FLAC file and a WAV file of the same quality, as well as a WAV file that has been zipped with compression and uncompressed.

 

in both tests the non compressed files sounded better.

 

Does this change your answer?

 

(sorry don't mean to be picky just trying to get opinions on what RAID will do, not necessarily express my findings on sound quality degradation)

 

ZFS properly guarantees file integrity after resilvering. If you are concerned about sound despite that you'll need to test it yourself. Note that one drive can never reconstitute 3. For every "extra" drive you can resilver with that number of failed drives eg for RAIDZ you can have a failed drive, RAIDZ2 allows 2 failed drives etc. I mirror.

[sedest]

I also use mirror. Plus incremental backups elsewhere.

[astrotoy]

ZFS properly guarantees file integrity after resilvering. If you are concerned about sound despite that you'll need to test it yourself. Note that one drive can never reconstitute 3. For every "extra" drive you can resilver with that number of failed drives eg for RAIDZ you can have a failed drive, RAIDZ2 allows 2 failed drives etc. I mirror.

 

I finally understand what you mean by resilver. When I was a kid, I built my first telescope, back in the mid late '50's. It was a Newtonian with a 6" mirror. I silvered the front surface and after a few months the surface became tarnished (like your mom's good silverware) and I had to remove the tarnished silver and "resilver the mirror" to make it good as new. Flat mirrors can have their coating in the back, with some protection so they won't get scratched and the silver won't get exposed to oxygen and tarnish.

 

So you resilver your mirrored drive to restore its sparkling data. So a RAID5 or 6 wouldn't technically be resilvered, since it wasn't a mirrored drive, only a RAID 1 drive.

 

Larry

[jabbr]

So you resilver your mirrored drive to restore its sparkling data. So a RAID5 or 6 wouldn't technically be resilvered, since it wasn't a mirrored drive, only a RAID 1 drive.

 

The analogy comes from mirrored drives but the terminology is used for both. When you "scrub" a ZFS device, you go through and look for mismatches between the checksum of a block and the redundant blocks. When a bad block is found, the redundant ones are used to replace it with good data.

 

 

Room treatments for headphone users