Is There Any Way to Repair Damaged Files Without the Need to Reprocess Anew?

[MrVideo]

I am compelled to put on the record to correct your claim.

I was referring to QNAP NAS products. Sorry I wasn't clear about that. As I've said, no one has complained about screwed up data on QNAP NASes. I have no clue as to what has gone wrong with the HP devices. That is not typical of NAS devices.

[childer]

...Your concerns are unfounded...

I am compelled to put on the record to correct your claim. As of today 60% of my 26TB video data is corrupt due to missing various subfolders and none of the movies with such corruption(s) is playable. Nevertheless, all of my movies in ISO files are intact, using the same old hp systems.

Since the discussions on this topic are exhausted, may I ask the Administrator to close this thread. Thanks,

[MrVideo]

Next question. Does the RAID system store a movie as a single unit, or as a file consisting of multiple component sub-files to be spread among all the drives for "balancing " purpose like that is being done by the HP media server? The main problem with the HP system is any failure in any sub-file of any movie in any drive can cause the entire movie file to be useless. That's why I am looking for a storage system to avoid this problem. Any idea? Many thanks for your efforts,

Look up RAID via google for a complete explanation as to how RAID works. But, in a nutshell, a file is broken up into pieces and spread across the RAID HDDs. The parity is computed and spread across the drives as well. If is file is below a certain size, I do not know what happens.

No one has ever complained about files becoming corrupted via QNAP NAS boxes. Whatever was going on with your HP systems, doesn't happen with QNAP (or other manufacturer's RAID products) RAID. It actually should never have happened with the HP either.

Your concerns are unfounded.

[childer]

No.

Next question. Does the RAID system store a movie as a single unit, or as a file consisting of multiple component sub-files to be spread among all the drives for "balancing " purpose like that is being done by the HP media server? The main problem with the HP system is any failure in any sub-file of any movie in any drive can cause the entire movie file to be useless. That's why I am looking for a storage system to avoid this problem. Any idea? Many thanks for your efforts,

[MrVideo]

Hi, Mr. Video, Thank you very much for the thorough answers. If I may, I have one RAID question, i.e., can I limit the failing data to a specific drive, say, the 1TB drive out of the other 10TB drives, so that I do not have to tax myself or the machine to hot-swap a 10TB drive. I currently plan to have a five-bay unit, using 4 drives in 10TB and, if possible, using one drive in 1TB for the sole purpose of asking the RAID to identify and shepherd the failing data to the 1TB drive for hot-swap, whenever necessary. Doable?

No.

[childer]

Hi, Mr. Video, Thank you very much for the thorough answers. If I may, I have one RAID question, i.e., can I limit the failing data to a specific drive, say, the 1TB drive out of the other 10TB drives, so that I do not have to tax myself or the machine to hot-swap a 10TB drive. I currently plan to have a five-bay unit, using 4 drives in 10TB and, if possible, using one drive in 1TB for the sole purpose of asking the RAID to identify and shepherd the failing data to the 1TB drive for hot-swap, whenever necessary. Doable?

[MrVideo]

Hi, the curing and hot-swap advantages provided by RAID is indeed marvelous. I will definitely pursue this route. But, I am confused by the two units you need for media playback and for storage. Can you play back directly from EITHER one, i.e., TS-451A or TS-869L, without the need to go through TS-451A first?

The TS-451A was a free unit from QNAP, as a gift for being a major supporter in the QNAP forums, i.e., helping others. The TS-869L is an older unit that I purchased strictly for storage (I'm not sure that they sell it anymore). While I tried doing DLNA with it, the app they provided kept failing. Instead I did DLNA serving from my Linux box to the Blu-ray player. With the addition of the TS-451A, the newer hardware allowed for HDMI output to my amp, which then fed the video to the display (computer monitor with VGA, DVI and HDMI), via Kodi17 (third party). The installed Kodi16 did not support the newest HD audio schemes. QNAP has an app that I installed on my Android phone that is a remote control for the TS-451A.

Also, do both models, TS-451A and TS-869L, provide RAID features? What is the maximum TBs for a bay to accommodate?

All QNAP, 2-bay and larger, units provide RAID. You need a 4-bay, or larger, for RAID5. I believe both will handle 12TB drives.

Everything you need to know is on the QNAP website. I suggest going there for more details. This forum is not a place for asking questions about NAS boxes.

[Darkore]

Make sure that you check all your options before you choose. I chose Synology because I like the versatility and upgradability of their hybrid RAID. I just needed inexpensive network storage because my media streamers (like DVDFab's) do all the work.

[childer]

Hi, the curing and hot-swap advantages provided by RAID is indeed marvelous. I will definitely pursue this route. But, I am confused by the two units you need for media playback and for storage. Can you play back directly from EITHER one, i.e., TS-451A or TS-869L, without the need to go through TS-451A first? In my current setting using hp media severs and San Digital extenders, I am handicapped by the inability to access the data in extenders directly, except through the servers. Also, do both models, TS-451A and TS-869L, provide RAID features? What is the maximum TBs for a bay to accommodate?

Sorry for stupid questions...

[MrVideo]

Great. In other words, whenever there is a failure, the raid system would identify the failed unit to allow it to be hot swapped for a new drive. After swapping, the raid system will restore the once-failed portion onto the newly swapped hard drive. Then, the system will operate healthily again like before until the next failure...

Correct. I do not know about other brands, but QNAP (I have a TS-451A for media playback and a TS-869L for data storage), has a led for each drive, so if it fails one, the led is turned red, so you know which drive to replace. When you have 3-4 drives, RAID5 is all you need. For 5, or more, drives, then RAID6 should be used. RAID5 has a 1 drive fault tolerance, while RAID6 has a 2 drive fault tolerance.

[childer]

Great. In other words, whenever there is a failure, the raid system would identify the failed unit to allow it to be hot swapped for a new drive. After swapping, the raid system will restore the once-failed portion onto the newly swapped hard drive. Then, the system will operate healthily again like before until the next failure...

Many many thanks. I will use the raid system; I should have learned it long ago.

[Darkore]

Hot-swap is a term referring to being able to swap the hard drive without turning the server off.

Fault tolerance in a raid refers to the number of drives that can fail at "one time" without affecting the integrity of the data.

All other questions are highly variable depending on the raid/hardware/server setup chosen.

[childer]

... I have my raid set up with a 1 drive fault tolerance so if any single drive fails I can replace that drive and rebuild the raid without any data corruption...

Hi, sorry for the delay to thank you, because I google-educated myself a bit more about RAID so that I can ask additional questions more intelligently.

After comparison, your method is the preferred one. But, I still have 4 more questions.

First, how can you identify which drive is failing? Second, once identified, is the hot-swap only needed so the server will rebuild the data automatically? Third, what is the optimal or minimum size of hard drive needed for tolerance? Four, do you need the same size of hard drives for the system?

If you can, please help me. My hearty thanks...

[Darkore]

"Raid" and "File System scrubbing"?.

I am not anywhere near an expert in this field, but these are the terms that the company Synology uses for their network servers. I have my raid set up with a 1 drive fault tolerance so if any single drive fails I can replace that drive and rebuild the raid without any data corruption. The scrubbing is a utility that comes with the Synology NAS servers to verify that the raid and the file system are still functioning properly. This helps protect you against any hardware corruptions.

If the corruption is caused by software, viruses, etc. the only way to protect yourself against that is BACKUP :-)

Please note, none of this will restore data that is already corrupt it only helps prevent corruption.

[childer]

...As long as you do the monthly Raid and File System scrubbing, you shouldn't have any problems sneak up on you. ...

You have rekindled my hope to store my digitized movies, using network servers. However, it is a major undertaking anew for me.
Can you educate me about the concept and process of "Raid" and "File System scrubbing"? I will follow your instructions religiously to avoid the digital massacre I have suffered.

Thank you again for giving me another new hope.