Important as in the data cannot be damage or missing? Then you will need store in system which have checksum to maintain it's integrity such as RAID-5 or BTRFS. You also need to have backup of the data. If use prebuilt NAS get at least 8 bays. 8TB HDD won't cut it anymore. 12TB HDD x 8 you will have 84TB usable space if use SHR-1 or RAID-5, this method 1 HDD failure you still can replace it and get back all data. But too many HDD means chance of more than 1 HDD failing is higher, use SH-2 or RAID-6 can have 2 HDD failure and still get back all data, but this RAID type only 72TB usable space. You also need to get additional HDD as backup copies. So maybe around 12TB x 8 for storage and 8TB x 7 for backup.

If it's just video where file integrity is not really important, example if some bit-rot, the video will have glitch on some time frame, it's still acceptable. Then you can just use each HDD as own volume without any RAID, then get same total capacity of HDD for backup so that when main HDD fail you still have another backup.

If the data is super important, best practice is to have 3-2-1 backup rule. Have 3 copies of the same data, at least have 2 different storage media (another in dvd, bluray, tape drive) of the 3 copies, and store 1 copy offsite (in the cloud or at other home/location)

Wouldn't it be better to suggest him 12 or 16 bay instead as he doesn't seem the type to have a limited budget
This way, he can actually achieve the 100TB he wanted

I didn’t set budget yet but off course the most value the best. Haha! Probably next year target, this year I had spend too much already.

Wouldn't it be better to suggest him 12 or 16 bay instead as he doesn't seem the type to have a limited budget
This way, he can actually achieve the 100TB he wanted

I use around 3 years fill up 50 TB. So I think another 50 TB is another 3 years.

Now you mention it, 12 bays will be a better choice.

With the storage requirement, you may want to consider unraid setup with 2 parity drives?

That is fast phase.

So you have to start with 50tb initial.

The best way I think is 12bay for the start.

7 x 16tb hdd with SHR Raid 5 to begin.

That would give you 6 x 16tb = 96tb and 1 redundacy. 96tb - 50tb =46tb free. This should last you for 2yrs+.

And each yrs, you can add 1pcs hdd or 2 to increase the size. Till max 176tb.

176tb max on 12bay can last you for 8yrs+ and more.

The 12bay is not limit yet. If use Synology.

12bay NAS can expand the storage to another 24bay. (12 bay expansion x 2 only storage without CPU)

That is the cheapest cost for easy setup and maintain I guess.

Synology DiskStation DS2419+ with 10 x 16TB HDD for 160TB storage
Another 2 x 16TB for redundancy. Should be good

And extendable in the future with another Synology DiskStation DS2419+

Really similar like having platinum credit card?

Usable storage if SHR-1/RAID-5 is 144TB, but since 10 HDD pool, having 1 HDD failure protection is kinda risky. SHR-2/RAID-6 would be better.
Andrewtst
If buy few HDD first and in future keep adding HDD with different size, it would be better to use SHR since it allow to maximized the pool according to HDD space
ozak
It seems there's no way in DiskStation to set a HDD as removable drive? I doesn't find if there's such option.

Hi, sorry may I know what is SHR. Thanks.

It's a RAID type, develop by Synology and only usable for their NAS. Classic RAID type size limited by the smallest HDD in the pool. SHR can maximized the storage without being limited by the smallest HDD. Can read here to understand more.
https://www.synology.com/en-global/knowledg...Hybrid_RAID_SHR

ozak
It seems there's no way in DiskStation to set a HDD as removable drive? I doesn't find if there's such option.

Remove able drive?

I guess that is a no? 
Something like this MyArchive
Internal HDD can be used as removable storage for keeping additional storage.
I guess having external HDD reader + internal HDD also can achieve same thing, only need additional hardware.

I prefer to have fix NAS hdd inside.

But how about RAID if using as removeable?

For the removable drive bay, it can't be part of RAID. Example usage on 4-bays NAS, 3 HDD in RAID, 1 bay for hot swappable HDD.

Usually can last around 5 years, but actual is depends on usage, how take care, type of HDD.
Best is get NAS HDD, as it design for continuous running and have vibration protection.

My experience from 2 bay to 4 bay and last, 8 bay.

If for personnel use less traffic, 2bay is ok.

The cons about 2bay is,

1) The only way to expand if run out of space is by HDD. No extra bay to expand. Both HDD have to change together.
2) The chance of both hdd spoil is high. Cause you normally buy the hdd together. Backup is like no backup. Unless you can buy hdd separate time and place.
3) it only provided 1 LAN to communicate. If the LAN port spoil, you can't access your data anymore. No spare LAN.

My 2bay last about 5yrs, 4bay last about 6-7yrs. Now using 8bay.

HDD lifespan very much depend on brand I guess.

I have WD red last 5yrs and some still running. Have Samsung last 8yrs and some still running. Have new seagate stil running fine.l

Ya I think my NAS have 1 hot swappable bay.

But put all in raid. I don't no what it is for. Feel kind of waste away the bay.

Mostly is to backup work files and images. Not streaming media unless want to get files for work. Like onedrive now.
Will use home unifi at 100mbs down 50 Mbs up. Makes a difference?

How much ram do I need? I am thinking of synology 4 bays. Can upscale right if use their shr technology?

Is there anything on DSM that indicate you can create pool/volume that can be removable?
I can't find such options. I google also can't find it got such function.

This ?