Hybrid RAID, 1 or 2 disk redundant

[sol1109]

I have a 4 bay Synology NAS that I need to setup. I plan to use the Synology Hybrid RAID option and need to decide if I want 1 or 2 disk redundancy upfront since you cannot convert between the two once you start. I know RAID does not serve the function of a backup so if this is for simple hardware failure protection what advice do you have? I plan to use the WD RED series of drives and my experience with WD over twenty years and about 6 home built PCs has been very good so I am leaning towards 1 drive redundancy unless someone can give me a good reason to go with two.

 

[DelJo63]

Just to be clear, your asking about one array Raid 1 (with two disks in it) versus two arrays of Raid 1 with two disks each.
Attempting "1 drive redundancy" with only one physical hd is illogical and invalid.

 

[LNCPapa]

I think he's asking if he should go RAID5 or RAID6. If I'm correct I would say it depends on how critical the data on this array is and how quickly you can turn around and replace a drive if/when it fails. Remember that using an array in Degraded Mode can be quite painful and sometimes very slow. If you have the resources to replace a drive very quickly and at any time then I'd say you're safe with RAID5. It'll give you HD * (N-1) capacity instead of (N-2) and still provide you fault tolerance. I have a Synology 1511+ myself that I run in RAID6 because I don't need more than the 6TB I get from it with that setup [ 2TB * (5-2) ]. This is for my small array that meets the need I purchased it for.

 

[sol1109]

Thanks for the response. I was referring to Synology Hybrid Raid not the standard raid types but that is a good point about how quickly could I replace the bad drive during which time I would be vulnerable with 1 drive redundancy. I have the DS412+ and have been trying to decide if I should fill it with the 3 or 4TB drives and how much usable space would be lost by the redundancy. I plan to use a good portion of it as a media server but have no idea how much room a DVD or blue ray takes up? LNCPapa, do you also have a backup strategy for your 1511+?

 

[LNCPapa]

Not really. The 1511+ is my backup solution for a couple of my desktops. My main array is another server sitting under my desk but it does not have any sort of backup which makes me nervous. It's also running RAID6 and I have a few extra drives sitting in a closet for cold spares. A typical ISO'd DVD takes anywhere from 4-8 GB while an extraction of a bluray (no such thing as blue ray afaik) averages from 20-40GB. Compressed using .264 you're looking at 700MB-1.3GB for a DVD and 4-10GB for bluray for decent qualities. Also, if you do your own home video that can be the killer. If you record in HD to tape (the HD recording cameras typically have lower bitrates) then the space needs might blow you away. My recordings take up to 61GB/80min. Then you need space for conversion and then space for the transcoded copy. I have a tendency to save my source data so I go through space pretty quickly. I also use my fileserver as my Plex Media Server for the rest of the devices in the house so I don't need any further duplication.