From scratch; 'resyncing' new drives is taking a week, should I be concerned?

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rn_enthusiast wrote:

I assume the drives are healthy? No errors on any of them?

 

You are likely limited by the CPU and RAM here. The RN104 houses a single core ARM chip and 512MB of RAM. It is very limited what this unit can do, in general. There probably isn't much you can do to speed it up :(. Just ensure your drives are at least healthy (hover over them in the GUI and check).

 

The other thing I would say is that with such a lower power unit, I would stay far away from letting it handle large volumes - especially if the data matters to you. IMO, letting this unit handle 20TB+ volumes is way beyond their use case. It is meant for basic home NAS needs on a small volume.

 

I fear for how this venture will turn out in the long run. Please ensure you have up-to-date backups at all times! :)

 

Happy new year.

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The drives appear healthy on the GUI, but they are only 5400rpm with little cache so I suppose that doesn't help.

I actually have two other RN104's running, since 2014 (!), which is why I figured I'd just stick with what I knew and trusted - although they are only 10TB and 8TB volumes respectively. I forget how long they took to sync. in fact I completely forgot everything about them as I haven't had to touch them except to move them around when decorating.

In terms of your fears for the venture can you expand? I get that data loss happens - there's nothing on these drives that I can't live without for example (which is not to say it wouldn't be galling) but as long as we aren't talking about potential physical hardware issues...?

I'm open to any suggestions for a better setup / model as well.

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rn_enthusiast wrote:

I assume the drives are healthy? No errors on any of them?

I am wondering if they are SMR, which could account for it.  

Although I'm not seeing a posted build time for 4x8TB on the RN104, there are a couple of times posted for other disk configurations on RN102 and RN104 models.  Though volume build times definitely will vary for different RAID modes (and for different disks), you can roughly estimate build speed by dividing the total disk capacity by the time it takes. 

When I apply those estimates to your system configuration, I end up with approximately half the time you are seeing (ballpark of 120 hours).

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rn_enthusiast wrote:

You are likely limited by the CPU and RAM here. The RN104 houses a single core ARM chip and 512MB of RAM. It is very limited what this unit can do, in general. 

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The RN100 speed is definitely limited by the CPU/RAM, and not the disks. 

I have some old logs that show volume build time for both the RN102 and the RN202 with 2x1TB Ironwolf disks.  This was done at about the same time, using the same firmware.  Volume build time for the RN102 took about 7 hours, the RN202 only took about 2 hours.  The RN202 build speed was therefore about 1 TB per hour, the RN102 was about 280 GB per hour for the same disks.

FWIW, just applying that 280 GB per hour speed to your 4x8TB configuration yields about 114 hours - that was one of the data points I used to guestimate the time your build might take.

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rn_enthusiast wrote:

 

The other thing I would say is that with such a lower power unit, I would stay far away from letting it handle large volumes - especially if the data matters to you. 

 

... Please ensure you have up-to-date backups at all times! :)

I always recommend having up-to-date backups on any NAS :smileyhappy:

To be more clear on the potential problems:

• RAID sync times (as you already see) will be much slower on the RN104 than other other models.  Disk Scrubs will also be much slower.
• The limited memory could also result in out-of-memory (OOM) crashes.

Long RAID sync times are of course annoying.  But more importantly, the volume isn't protected during the sync.  So longer sync times also make the volume more vulnerable - the odds of a second disk failure happening during the sync go up some, as do the odds of a power failure or some other event disrupting the sync.

OOM is IMO more concerning than the RAID sync time, because any crash risks an out-of-sync volume due to loss of cached writes.  You can lower the risk of OOM crashes by being careful about the services you enable on the NAS (and the apps you choose to install). 

For instance, don't enable AFP, NFS, or even FTP on the RN104 if you don't really need those services.  Similarly for ReadyCloud and other cloud apps.  Plex can potentially lead to problems - it does use quite a bit of memory.  So if the NAS hangs up when Plex is scanning your media library, then consider moving Plex to a PC (mapping the NAS media shares to one or more drive letters).

One option to work around the RAID sync times is to use JBOD (with four 8 TB volumes).  Then there is no RAID sync needed - but also no RAID redundancy.  I've done this on both the RN102 and the RN202, in order to max the capacity.