SHR, RAID 5, and RAID 6: What They Are and How They Work
When setting up a reliable storage and backup system, one of the most important things you can do is choose the right RAID type for your Synology NAS. The way you set up your RAID affects how much space you can use, how well it can handle errors, how long it takes to rebuild, and how safe your data will be in the long run. Synology has its own flexible option called Synology Hybrid RAID (SHR) in addition to traditional RAID levels like RAID 5 and RAID 6.
What RAID Can and Can’t Do
RAID is meant to keep your data safe from drive failure, not from accidental deletion, ransomware, or data corruption. A RAID array keeps systems running even if one disk fails, but it doesn’t take the place of backups. For full data protection, RAID should always be used with snapshot protection and backups that are stored off-site.
What is Synology Hybrid RAID (SHR)?
Synology’s own RAID option, SHR, is meant to make managing storage easier and make the most of available space. It is very helpful when you have drives of different sizes in the same NAS.
SHR automatically optimizes how data is spread out across disks, so users can use drives of different sizes and still have redundancy. Adding bigger drives later, for instance, doesn’t waste space like traditional RAID often does.
SHR is great for:
- Businesses that are small or medium-sized
- Growing places to store things
- Users who want to upgrade their drives step by step
- Teams that want to be able to change things up without having to plan RAID by hand
SHR with one-disk fault tolerance and SHR-2 both offer protection that is similar to RAID 5 and RAID 6, respectively.
What RAID 5 Is
RAID 5 is a common and traditional RAID level that protects against the failure of one drive. It spreads parity data across all disks, so the array can keep working even if one drive fails.
RAID 5 is a good choice for file servers and backup repositories because it strikes a good balance between usable space and protection. But all the drives need to be the same size so that no space is wasted.
RAID 5 is best for:
- Stable places with drives that work together
- Storage sizes that are not too big
- Systems where rebuilding doesn’t take too long
Longer rebuild times mean more risk during recovery as drive sizes get bigger.
What RAID 6 Is
RAID 6 is an improvement over RAID 5 because it protects against two drives failing at the same time. This extra layer of redundancy is useful in big arrays where it can take hours or even days to rebuild.
RAID 6 has less usable space than RAID 5 because it uses double parity. But in places where uptime and data integrity are very important, the extra safety is often worth the trade-off.
RAID 6 is a good choice for:
- NAS systems with a lot of storage space
- Storage that is critical to business
- Backup targets that stay for a long time
- Places where the risk of having to rebuild must be low
A practical comparison of SHR, RAID 5, and RAID 6
SHR is clearly the most flexible option. It lets you grow slowly and use different drive sizes without wasting much space. RAID 5 and RAID 6 need more planning ahead of time and disks that are all the same.
RAID 6 and SHR-2 are better at protecting data than RAID 5 or regular SHR. This is more and more important as the storage space on each drive gets bigger.
From a business point of view, SHR makes administration easier, while traditional RAID makes sure that things work the same way every time in environments where strict standardization is needed.
Things to think about for performance and rebuilding
In most real-world NAS setups, how well these RAID types work together is less important than how well they can be rebuilt. It takes longer to rebuild larger disks, and the array is under stress during that time.
RAID 6 and SHR-2 lower the chance of losing data during rebuilds by letting one more disk fail. This is very important for modern NAS systems that use high-capacity drives.
What kind of RAID should you pick?
For small and medium-sized businesses that want to be able to grow and change, SHR is usually the best option. For smaller arrays with drives that are all the same and a moderate level of risk, RAID 5 can still work. For bigger arrays, important data, and long rebuild windows, RAID 6 is the safer choice.
The best choice depends on the size of the drive, the number of bays, how much you expect it to grow, and how much downtime or risk you can handle.
RAID Is Just One Level of Safety
No RAID setup can take the place of real backups. RAID keeps systems online, but snapshots, replication, and off-site backups protect against data loss scenarios that RAID cannot address.
About the Epis Technology
Epis Technology helps businesses create strong NAS environments by providing enterprise IT infrastructure, data protection, and Synology consulting services. The company is an expert in Synology storage architecture, RAID planning, backup strategies, and solutions for keeping a business running. Epis Technology makes sure that data is always available, safe, and scalable as business needs change by choosing the right RAID setup and adding layered backups.