What Is SHR? What Are the Differences Between It and RAID?

What Is SHR?

What is SHR? SHR is the abbreviation of Synology Hybrid RAID, which is Synology’s automated RAID management system. SHR allows users to create flexible storage solutions with optimized capacity and performance.

SHR is based on a Linux RAID management system and is designed to make storage deployment faster and easier than classic RAID systems. This makes it especially suitable for users who are not familiar with RAID technology. However, not all Synology NAS models fully support SHR.

How Does SHR Maximize the Storage Capacity?​​

Typically, classic RAID creates its storage based on the smallest drives in the storage pool. Unlike classic RAID, SHR divides each drive’s storage space into smaller chunks and creates additional redundant storage. SHR also outperforms classic RAID in storage expansion. SHR, on the other hand, allows expansion of the storage pool immediately after upgrading two drives and can form redundant storage arrays.

How to Expand the Storage Capacity of SHR?

You can expand the storage capacity of an SHR storage pool by replacing existing drives with larger capacity drives or adding additional drives.

1. Replace a Larger Drive

Replace one drive at a time and use Storage Manager to repair the storage pool. Make sure the replacement drive meets the drive requirements. For more information and detailed instructions, see the corresponding help articles for DSM 7.0 and DSM 6.2.

2. Add Another Drive

Insert drives into empty drive slots and add them to the storage pool. Make sure the additional drive meets the drive requirements. For more information and detailed instructions, see the corresponding help articles for DSM 7.0 and DSM 6.2.

Synology Hybrid RAID vs Ordinary RAID

When you buy a Synology NAS and are ready to set it up, you will have to create a storage pool and volume. When you create these projects, your task is to choose the RAID type, which is where the Synology RAID Calculator comes in.

Often, you want to ensure that there is some form of redundancy. Redundancy ensures that if one of your hard drives fails, your NAS will be able to rebuild that drive using the other drives that are currently available.

Now, let’s see the differences between Synology Hybrid RAID and ordinary RAID.

Advantages of SHR

• faster setup.
• Scalable.
• Ability to mix drives.
• Provides more usable capacity when mixing drives while still maintaining 1-disk redundancy.
• Drives can be moved to new SHR-enabled Synology, new NAS will see volumes and data.
• In the event of a drive failure, Synology can still access the full volume data – albeit at a much slower rate until a replacement drive is installed.

Disadvantages of SHR

• Slightly slower than traditional RAID, but the same speed as RAID 5 and 6.
• You cannot remove the drives from the SHR RAID and install them into a new non-SHR NAS, they need to be formatted.

Related post: RAID 5 VS RAID 6 on Benefits, Performance, and Application

Advantages of RAID

• Wider deployment options. More task-specific RAID sets are available, such as RAID 10 or RAID 50.
• Hard drives are more likely to be recognized in new NAS/DAS enclosures if you are installing them in new equipment.
• Still scalable between RAIDs, but not as good as SHR.
• Overall, provides better read and write speeds.
• Not limited to Synology.

Disadvantages of RAID

• You can’t mix drives efficiently, and most likely you can only increase total capacity by replacing all drives in the array.
• Data inaccessible after drive failure until new drive is installed (except RAID 1).
• Compared to the same SHR, it takes significantly longer to create a RAID array.