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Any Thoughts About Network Attached Storage (NAS)?

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x9200
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Postby x9200 » Fri, 29 Aug 2014 8:38 am

Brah wrote:@X9200 - Thanks for the continued suggestions. Any issue I may have with RAID is a) any assumption that it is an alternative to backup for disc failure, and b) for a 2x config, that it is not much safer than 1x, and less safe than 1x with a backup.
[..]
Why I regard RAID >1 higher that RAID 1 is that that involves more drives = less likelihood of total loss (save for things like fire, flood, theft, etc. ). Like you said, you could have RAID 1 with >2x but not sure why anyone would do that.

Unfortunately it is the other way around. Lets assume the probability of a single drive failure over a period of 5y is 10%. This means, if you have an array made of 10 drives the probability of a failure within this array within 5y is 100% (vs 20% for R1 with 2 drives).
Besides, for R1 you have always 2 ready copies. If one fails, you replace the drive and your protection level is immediately restored. If 1 drive fails within an R5 array and you replace this drive with a good one it still takes hours to rebuild the array. If another failure happens during the rebuilding, and this is really very intensive drive work time, then all the data is or could be gone. This is a pretty serious threat as this is linked to something know as unrecoverable reading error (URE) that is said to possibly happen roughly once per 10-15TB of data read from the disk. This likelihood is defined in the harddrive spec. and I personally think it is a bit overdone but nevertheless it is something real. It never happened to me and I've been using R5s for 7 years at this point rebuilding the arrays a few time but still.

One important clarification: I am recommending RAIDs, as an n-copy of the data and never as a single archive unit. I assume that you will have at least:
1. original data on the original storage
2. a copy of the above on a RAID
so under normal, system healthy circumstances you will have at least 2 copies of the data of which one is RAIDed.

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Postby QRM » Fri, 29 Aug 2014 12:12 pm

Weakest link is the mug at the keyboard, I have a synolgy 2 disk NAS set up and a disk failed, warning came up, I bought a new disk and slotted it in. The theory was the good disk should copy over data to the new disk, then for some odd reason I went and formatted the existing disk thinking it was the new one! lost everything. :mad:

Lucky for me I had an old external disk I used to back up my desk top a year previously so at least that contained most of the archive stuff.

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Postby durain » Fri, 29 Aug 2014 8:45 pm

QRM wrote: I went and formatted the existing disk thinking it was the new one! lost everything. :mad:


OUCH!!!

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Postby Brah » Sun, 31 Aug 2014 12:14 pm

I plan to reply to this thread in a few days, after I speak (again) with WD Support on the drive replacement options.

I seem to remember I may unable to buy a new disc as this enclosure is considered out of service. This array only takes WD drives.

Next time I buy something generic.

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Postby Steve1960 » Tue, 16 Sep 2014 3:02 pm

Brah wrote:I plan to reply to this thread in a few days, after I speak (again) with WD Support on the drive replacement options.

I seem to remember I may unable to buy a new disc as this enclosure is considered out of service. This array only takes WD drives.

Next time I buy something generic.


Any further progress with this?

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Postby Brah » Tue, 23 Sep 2014 11:21 pm

Not yet Steve, have not had the time to get the backup and replacement discs and 'do the needful' as they say here.

WD did confirm that I can't buy replacement discs for this enclosure. Last time I buy an enclosure that can't be updated. Buyers beware.

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Postby x9200 » Wed, 24 Sep 2014 4:27 am

But you wrote earlier this:
WD MyBook WD20000H2U-00, 2 1tb Seagate drives. The Seagate drives were originally in the WD enclosure?

I was recently told in Best Denki that I could not stack up different brands of the washing machine and the dryer within a single stack and only after some arguments the sales expert admitted "unless you can do it by yourself".

It's hard to believe no other 1TB WD drive would work with this enclosure. Maybe what they meant was that you could not replace a single drive because it should match the old one remaining and this model was already phased out. Still questionable but in some aspects possible.

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Postby zzm9980 » Wed, 24 Sep 2014 8:00 am

It's possible they artificially limit it to specific models of drives in the enclosure's firmware.

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Postby Steve1960 » Wed, 24 Sep 2014 11:13 am

x9200 wrote:But you wrote earlier this:
WD MyBook WD20000H2U-00, 2 1tb Seagate drives. The Seagate drives were originally in the WD enclosure?



That surprised me too as the companies are direct competitors. WD says the enclosure 'will only take the WD Caviar GP drive'.

A quick Internet search says they are still available refurbished on Amazon.

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Postby x9200 » Wed, 24 Sep 2014 11:15 am

zzm9980 wrote:It's possible they artificially limit it to specific models of drives in the enclosure's firmware.

Yes, I know but it would be utterly stupid IMHO.

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Postby x9200 » Fri, 10 Oct 2014 5:31 pm

duderito wrote:You can also just turn a laptop into a NAS quite easily and then you have a machine that is much more powerful than a NAS.

So is a vacuum cleaner but its power does not translate any way to improvement in the NAS functionality/performance.

duderito wrote:In my opinion, unless you need to save some money on your electricity bill, a laptop or mini pc is always preferable to a NAS.

And the reason is?

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Postby x9200 » Sat, 11 Oct 2014 7:38 am

If using laprop is more convenient to you, fine, fair enough, but I would suggest replacing the word "always" with something more modest.

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Postby Brah » Sat, 11 Oct 2014 8:50 am

Though I have yet to have the time to deal with this drive, I can't for the life of me remember why I said they were Seagates in the enclosure, they are WD Green drives.

x9200 wrote:
zzm9980 wrote:It's possible they artificially limit it to specific models of drives in the enclosure's firmware.

Yes, I know but it would be utterly stupid IMHO.

And they are, even more stupid than me thinking I had Seagates (which I think are in my D-Link NAS).

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Postby bgd » Sat, 11 Oct 2014 10:57 am

duderito wrote:Because a laptop will always be more versatile. The OP was also speaking about using Plex which if he needs to transcode will require more processing power than a NAS has. If the NAS only ever needs to serve files then they make sense. I prefer to have my options open so my HTPC is my NAS at the moment and I have seen no viable benefits to adding a NAS to my media server solution.


I have recently found that streaming to VLC was, occasionally giving me drop outs. I got round this by copying the entire file to the computer hard drive and then playing from that. Might be an example of a performance limitation but I couldn't see any obvious cause, nothing was maxed. Also only on wireless so that could be a factor. However as a file store I'm very happy with NAS.

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Postby x9200 » Sat, 11 Oct 2014 11:24 am

NAS is typically more hardware optimized towards its main function. Unnecessary versatility is seldom a good thing for the performance of the primary function - you just can't do well everything at the same time.

Also for many NASes it is possible to flash them with highly customizable software and it will run on a platform optimized for NAS. No laptop can come any close to this.

Another reason why I would never use my laptop for any serious storage task is practicability and scaleability. How practical and safe is to have laptop with a drive attached via a cable? Unless the internal hard drive is the base of the whole NAS thing but what if I need more space?


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