What is the difference between SHR and RAID?

Synology Hybrid RAID or SHR, has been around for a long time now, and however it has not had the huge effect that Synology NAS’ Btrfs file system has, it is as yet an expanding well-known decision for some with regards to ensuring their equipment and their information in a Hard Drive enclosure. The two NAS and DAS use RAID as a type of security from a HDD or SSD damage and the outcomes of data misfortune that can occur. It ought to consistently be featured that both conventional RAID and SHR are NOT types of Backing up and you ought to ALWAYS have an offsite or at any rate off-system mirroring set up making constant data images and duplicates of your critical data. Be that as it may, returning to the current subject, which strategy for redundancy would it be advisable for you to consider for your capacity cluster — RAID or SHR?

What is RAID?

Huge RAID storage for file data storage arrangements RAID, or Redundant Array of Independent Disks, was initially numerous years back as a method for joining heaps of littler discs together to make a lot bigger capacity volume, with redundancy as an auxiliary need. In any case, with the enormous scale development of Hard Drives these most recent 5 years and that’s just the beginning, with Terabytes of data getting to be accessible on single discs, the essential concern of RAID has moved towards data assurance.

It is not necessarily the case that pooling little drives does not still occur, yet with drives right now is possible to purchase an 8TB such at the Seagate Archive Drive, you can perceive any reason why the motivation behind RAID in file and cold storage is increasingly about data assurance.

How does Synology SHR work and how is parity data distributed?

SHR is far more automatic RAID choice and designed for the less technically minded to protect their data from hardware failure, without having to delve to deeply into complex matters like parity and striping. It is also significantly easier to set up and considerably more scalable than traditional RAID.

It is not supported on all Synology NAS server devices but I would recommend checking in advance that your chosen Synology NAS can utilize SHR here. But otherwise if your NAS can support it, SHR arrives with a host of benefits both in terms of deployment speed and in maximum available capacity.

SHR doesn’t arrive in multiple types like RAID, but in just two different versions. SHR and SHR-2. SHR gives you the ability protect your data from 1 lost hard drive and SHR-2 protects you from two. However, the key strengths in a Synology SHR RAID setup is:
You only need two disks to build an SHR array and after that you can add drives to the Synology Hybrid RAID at any time.

In an SHR Volume, you can mix and match Hard Drives and let the calculations of the SHR layer do the work. This isn’t just at the moment of installation, but anytime you like. So, if you have for example 4 x 2TB drives in an 8-Bay enclosure and at a later date add 4x 4TB drives, not only will you be able to add these larger drives of any BRAND or speed, but also get the much, much bigger total capacity made available to you.

With an SHR RAID, regardless of the mixing of the drives, in terms of redundancy vs Capacity, you will only lose 1x the largest drive. Whereas in a RAID 5 if you mixed drives, ALL of them will be viewed and RAID’ed as the smallest available drive and you still only have redundancy for a single drive. So, in practice:
Like traditional RAID, SHR will provide you with the ability to protect your data from the loss of a single HDD or SSD. However, with SHR-2 you will be protected from losing 2 HDD or SSD.
Slightly less speed than a traditional RAID. Less than 1% difference between SHR and RAID 5, for example.

SHR vs RAID — Which is better?

And so, down to business. Now you know what SHR and RAID are, what is now important is which should you choose. Both are excellent methods of redundancy and have their own benefits. But lets take a look below at their strength and weaknesses:

SHR Strengths

1. Faster to setup
2. Expandable
3. Ability to mix drives
4. Greater available capacity when mixing drives whilst still maintaining 1 disk of redundancy
5. If a drive fails, the Synology can still access the full volume data — though will operate much slower till a replacement drive is installed
6. Drives can be carrier over to a new SHR supported Synology and the new NAS will see the volume and the data

SHR Weaknesses

1. A little slower than traditional RAID but equal speed to RAID 5 and 6
2. You cannot remove the Drives in an SHR RAID and install them in a new non-SHR NAS, they will need to be formatted.

And now onto Traditional RAID
RAID Strengths

1. Broader options for deployment. More task specific RAID sets like RAID 10 or RAID 50 are possible
2. Better chance of Hard Drives being recognized in a new NAS/DAS enclosure if you install them in a new unit
3. Still scalable between RAIDs, but not as much as SHR
4. On the whole, better Read and Write speeds available
5. Not just limited to Synology

RAID Weaknesses

1. You cannot effectively mix drives and to increase the total capacity will in all likelihood only be possible by replacing ALL drives in the array
2. Cannot access the data after a drive failure until a new drive is installed (exception of RAID 1)
3. Takes noticeably longer to create a RAID array compared with likewise SHR

RAID or SHR — The Result
Choosing between SHR and RAID on my Synology NAS with Hard Drive Media It probably won’t come as an enormous shock when I say that I recommend using SHR when using a modern Synology NAS. The benefit in the scaling options alone made it a real standout choice for me and for those who are brand faithful, you would only make it more convincing. Traditional RAID is still very relevant and very, very useful. But if you have the option to adopt SHR in your NAS setup, I urge you to do so at the point of installation.