I've been a satisfied Drobo (www.drobo.com) for many years. Unfortunately, they are going out of business, and I need to find a replacement.
The features from the Drobo that I want are:
Drive redundancy - If a single drive mechanism fails, there is no data loss.
Auto healing - If a single drive fails, and there is enough available space, the data is automatically redistributed to protect against another drive failure.
Expandability - replace a smaller drive with a larger drive and the device makes the additional space available
Optimistic provisioning - I can create virtual drives that are larger than the actual physical disk space. Obviously, you can't use more space than what exists, but as drive capacities go up, and drive prices come down, I can swap in larger drives and the use the space.
Mac Compatible - Presents a Mac native file system to my Mac (either HFS or APFS).
Allows direct connection over a fast channel - I can connect my Drobo over Thunderbolt to my Mac, and it the volumes appear as external disks.
As I have been using Drobos, I am not familiar with the other products that are out there. Are there other products that have the above features? Which do people recommend?
A Synology NAS can do everything apart from Optimistic provisioning (and it may be able to do that for all I know).
I've got 3 scattered around - a main one with 32Tb of space and 2 backup ones. I use it for:
Centralised data storage and sharing
Web
Photo viewing
It's my media server for movies & TV shows that I have.
I store data from 6 cameras on it (survellience)
Maybe "optimistic provisioning" is the wrong term.
What I want to be able to do, is to expand the available space on a volume, without having to go through a lot of hassle.
With the Drobo, the method was to create a 16TB volume, even if you had less space than that. As you added more drives (or replace a smaller drive with a larger one), there was more useable space. This had the advantage that I could create multiple large volumes, and not have to worry about how much space to allocate to each. As long as I was using less than the physical storage, everything just worked. There's a series of lights on the front of the Drobo that tells me about what percent of the physical space I am using.
The best part is that increasing storage really was as simple as popping out a small drive and replacing it with a larger one. No need to power down, and no need to run any management software. The lights on the front of the Drobo would tell me when it was safe to pop out another drive.
I would be just as happy with creating a volume whose size matches available space, and having the volume size increase when I added more physical capacity.
With the Synology, can I easily swap in larger drives to increase the available storage space on existing logical volumes?
Does the Synology alow direct connection (via USB-3 or Thunderbolt) so it can be used like an external disk? (I think USB-3 and Thunderbolt are faster than gig ethernet)
As far as I can tell, you want a DAS (Direct Attached Storage, ones that are directly connected to your computer) instead of a NAS (Network Attached Storage).
Ohh.. if that's the case, there is a lot of NAS boxes from QNAP or Synology that should be sufficient for you.
Of course if you use the common 1 Gbps interface, you're going to get much slower transfer speed than what you're used to. That's the trade-off.
Some boxes allow you to upgrade the network interface to 10 Gbps and even more. But then again you will also have to upgrade the your whole home network infrastructure. You have to use a switch (hub) that also has 10 Gbps interfaces, for example.
How about this one. I don't know your budget but I think it's available for around USD 900 without any disk included. www.qnap.com/en-us/product/ts-673a
This is easy with a Synology NAS if you create a volume using the SHR raid protocol. This allows you to take existing disks (say 4 x 6Tb) which will give you 18 Tb to play with (it's like RAID 5 in that one disk is for parity) but if you need more space, just replace one of the disks and the volume will increase.
So, I had exactly that - 4 x 6Tb and was running out of space. I bought 4 x 12 Tb disks and replaced them one by one. Each one took about 12 hours to resynch - at the end of it I had oodles of spare space. I'm actually running RAID 5 so the increase wasn't noticed till I put the last disk in.
From the help on SHR:
Synology Hybrid RAID (SHR)
Synology Hybrid RAID (SHR) is an automated RAID management system, designed to simplify storage management and meet the needs of new users who are unfamiliar with RAID types.
SHR can combine different sized drives to create a storage volume with optimized capacity and performance, wasting less drive space and providing a more flexible storage solution. When sufficient drives are included, SHR allows for 1- or 2-disk redundancy - meaning the SHR Volume can suffer up to one or two failed drives without experiencing data loss.
For more information on SHR, refer to this article.
Plus, if you get the right NAS box, you don't even have to power down the box to replace the disks.
I think so. I have a DS916+ which I find plenty fast enough. It's only a 4 bay one, but you can add another 5 bay extension box to it. If you want a 5 bay box, go for the DS1522+
RAID 5 is sufficient for your requirement, although you still need to consider the time needed to rebuild the array in case of drive failure. Will your business be able to withstand >12 hours of non-operation period during the rebuild?
If the NAS has at least 4 bays, then you can allocate 3 of them for the RAID 5 array, and allocate the last bay for what some manufacturers call hot spare disk. I think this is what you meant by 'auto healing'.
I use RAID 6 with a hot spare to reduce the possibility of losing data due to a drive failure during a rebuild. With 1 TB disks the rebuild times weren't that long, but with 18 TB ones, they sure are. Don't forget to configure a hot spare if your NAS is unattended for very long.
Do the QNAP products offer the same ability to increase capacity of existing volumes simply by swapping in a larger drive?
I suspect I don't need to upgrade the whole network to get faster than gig speeds on a NAS. I can affordably add a 2.5G ethernet with a USB dongle. That can be a direct connection to the NAS, and I can retain the existing 1G ethernet for everything else (this will require a little network config on my Mac, but that isn't that difficult).
I'd like something a little more sophisticated than simple RAID 5. My understanding is that requires all drives in the set to be the same capacity (if some are larger, you can't access the additional capacity).
With the Drobo, I could have a 4TB, two 6TB, and two 8TB drives, and all would be used. My available capacity would be 24TB. The Drobo could tolerate the loss of any drive without data loss.
When a drive fails, there is no loss of data. If any of the drives died, I could pop it out, and slide in a new 8TB drive. The Drobo would immediately start integrating the new drive into the set, with no downtime. If the new drive was larger than the drive it was replacing, the additional space would be useable.
If I had a lot of available space, and I lost a drive just after I went home on Friday, the Drobo would reshuffle the data to protect itself for the loss of another drive. When I came in on Monday, the Drobo would be running with full redundancy with the remaining four drives. I could replace the failed drive, and it would be integrated. The Drobo can also be configured to have dual drive redundancy, and then it can tolerate the simultaneous failure of two drives.
I really like the ease of use. When I bought the Drobo, I started with two 4TB drives, and three empty bays. As I needed more space, I simply added a new drive to an empty bay. As prices dropped, I started using larger drives, but I could also add capacity by filling an empty bay with smaller drives. Once all the bays were full, I could add capacity simply by popping out the smallest drive and replacing it with a larger one. Again, no need for downtime, nor a need to muck around with management software. Once the Drobo is set up, it really is trivial to use.
My understanding is that the modern NAS systems offer many additional features. Some offer mail servers, Security camera recorders, web servers, etc. I just need a fault tolerant disk, that's easy to use, and easy to expand capacity as my photo library grows.
I get the impression that Synology and QNAP seem to be the most popular choices. Both seem to offer a wide range of products, each with many features. I get the feeling that some products are more focused on functions other than NAS. For instance, I think (and I could be wrong), that some Synology products don't support SHR volumes, and hence you don't get all those nice features.
I am also not sure which products support Mac native file systems.
If you look at the above diagram you can see that even if you mix and match drives with different sizes, you have to create multiple "shares". You can think of a share as an extra disk attached to your computer via network. We cannot create a share that spans multiple array groups.
So, again from the above diagram, you cannot create a single share with 5 TB (2 + 1.5 + 1 + 0.5 TB) of redundant storage.
It's easy to see if a Synology NAS box supports SHR or not: just take a peek at its datasheet. I think almost all recent boxes support the feature.
Regarding file system, since this is what is called 'file level storage' (instead of 'block level storage'), you don't need to worry about whether or not they support Mac native file system. You access the shares via a network protocol. Apple has its own protocol called AFP, but it looks like it's deprecated. Instead, you can access your shares from macOS via a protocol called SMB which is a native feature of the OS.
You can add up to 2 expansion units (DX517) if later you think you need more bays.
You can also add a 10 Gbps network interface card (E10G22-T1-Mini) if you need more speed!
With Raid5 and SHR, if a drive fails, the system will carry on supporting the users - it's just you have lost redundancy, it runs a bit slower and it beeps at you ALL the time (don't ask me how I know). What you do (assuming you haven't configured a hot spare) is pop the duff disk out, put a new one in, select repair from the DSM console (your PC) and leave it to sort itself out. There is no 'downtime'.
Understand that there’s a big difference between a DAS and NAS, because DAS is way, way faster. And there are DAS models which accept flash drives, so you can have either all-flash or use a flash drive as a cache to boost speed.
NAS boxes are mostly Gig Ethernet, and with a cable, you’ll get about 100 MB/sec at best. I get around 80. Not saying that they are bad, but you need to understand the difference. 10 Gig is still fairly expensive.
I had a Drobo C for a long time. I was never impressed and it would often fail to mount, so I bought a Synology DiskStation 418, when it was on sale for $300. The newer Synology boxes have USB 3.1 but I don’t know how fast they run as DAS.
Synology is more complicated to set up than a Drobo, which is why I started the Synology thread. But they do way, way more than Drobo. Synology is a Linux computer with software that manages the RAID and provides a bunch of apps for all kinds of backup and sharing. You can backup ten computers in your home or share files on the internet or stream videos to your tv or use it as a video surveillance system, and probably more than that.
