Synology NAS RAID Levels Explained

Reviewing Synology's excellent RAID guidelines between the lines. Explain Synology Hybrid RAID and RAID 5, RAID F1, RAID 6 & RAID 10.

Synology's Important Considerations when creating SSD Cache

Timestamps:
00:00 Intro
00:53 RAID Choices
02:46 Synology Hybrid RAID
06:21 RAID 5
10:31 RAID 6
13:47 RAID 10
17:08 SSD Caching

[privacyproshop]

Let's explain what you see there:
1. Five drives: 500GB, 1TB, 1.5TB, 2TB & 2TB = 7TB total disk space
2. Fourteen separate 500GB partitions: four each on the 2TB drives, three on the 1.5TB drive, two on the 1 TB drive & a single partition on the 500GB drive
3. Partitions are made into four redundant arrays: 2TB usable RAID 5 array, 1.5TB usable RAID 5 array, 1TB usable RAID 5 array & 500GB usable RAID 1 array
4. Then the arrays are striped together to create the pool with a total of 5 TB of usable space.

What is the practical impact of this:
1. It is slow. Parity has to be calculated for three RAID 5 arrays and then one RAID 1 mirror SIMULTANEOUSLY, but instead of having 14 separate 500 GB drives, you now have 14 500 GB partitions over five drives. Think how much the drive heads have to move from partition one to the next on the drive - the drive motors are gonna wear out way too soon.
2. If and when one of those drives dies the pool is going to be completely unusable. Good luck restoring the system before another drive dies.

Now you can probably see why Synology wants to have no part of SHR in their Higher-end models.

[NikolaiWilding]

Thanks, wonderful dry sense of humour and good information. RAID 10 is the only choice if we want redundancy and speed for something like video editing. For backup's and maybe watching your movies, as a home user, RAID 5 or SHR1. If you earn money from making video's with more than one user using that data then must BE RAID 10. I've always considered RAID 5 FOR BACKUPS RAID 10 FOR SPEED when in both cases some redundancy is needed.

[Bakin]

Thank You! I have been searching for an analysis of RAID 10 that made sense to me.

It seemed on pure logic that RAID 10 in a 4-bay or 6-bay NAS had many advantages over Raid 5 or Raid 6. Your video hit all of the points that my own less experienced analysis found but being less experienced I had some doubts that so many YouTube experts seemed to overlook Raid 10. Thank you for setting this straight and using Sinology’s own technical guidance to make your points!

[KiarahJugares]

Thank you very much for this video, it is exactly what I needed. I'm doing my best learning Linux, ZFS, and other fascinating things and just purchased my first NAS (Synology) for archival purposes. While its shipping I wanted to double check which RAID to use (I thought it was RAID 5 or 10 by default). Thank you very much for being very clear about everything and what the most practical uses for each was.

[wldtuwe]

I wish you could cover more topics and run the influencers through the mud. Nothing better than getting correct information. You know, not the videos that YouTube favors that may or may not be wrong information. Your video? Not many views. But look at the f'ing information! Pure gold. This says to me everything that is wrong with YT and search engines. Sad. Thank you so much for this video. I have piles of notes from it. Pure gold content.

[joelnrs]

Not only did I learn a lot…the humor was wonderful. Great video!

[AlexK]

Excellent video... no nonsense and to the point!

[weiyen]

Hi Tim, I was troubleshooting my Synology performance issues with SSD with my Vcentre cluster. I didnt do my due diligence and went with SHR1 which I found pretty quickly that the performance was crap. After watching this video I redid the volume to Raid 10 with some optimizations at the Vcentre end, and the performance difference was so obvious it isnt funny. I am in the middle of transferring my vms from a slower storage nas to the synology so will be seeing how it performs. But so far it looks good. Your video was the only one that explains how the cavaets between the different Raid types. I love the humour. Hit the point home very well.

[kpetsas]

Very interesting presentation of the different types of raid especially about video editing, and with a good sense of humor.
Which of the following 2 setups do you think would be most beneficial in the case of an 8-bay NAS for video editing:
1) 8 x 16 TB spinning drives in raid 10?
2) 4 x 16 TB spinning drives in raid 5 (cold storage) and 4 x 4 TB SSDs in raid 5 (hot storage - editing)?
The costs of disks and total available storage (64 TB vs 60 TB) are equivalent in both cases.
I tend to believe that the second solution would be better, especially for speed, but I'd be happy to hear your opinion.
Thanks a lot

[jedichurn]

Hi, I’m a newbie at this and have been watching the YT videos you shown on yours. Thank you for the information on the different RAID. I have a few more questions, if you don’t mind answering

I think I would get the Synology DS1821+ which has 8 bays. It will be used for personal and small business use such as web hosting for a blog (personal), video editing (personal), accessing large files (CAD, Revit, 3D modeling) by 8-10 people (small business).

For above scenario and RAID 10
1) Do I need to fill all 8 bays immediately?
2) Do I do all SSD or all HDD?
3) Can I do half SSD (To work on) and half HDD ( for storage)? If yes, can the SSD storage be (4x4TB) and the HDD (4x20TB)? 16tb to work on, 80tb for storage)?
4) Can it be 2 SSD and 6 HDD? or 3 SSD and 5 HDD? So the split is always 4:4 (2 SSD + 2 HDD = work on) & (4HDD = storage)?
5) Do you have any recommendations for NAS SSD and NAS HDD?
6) Does the 80% capacity only pertain to HDD? Does it include SSD?

I would greatly appreciate any help you can provide.

[czummo]

As someone who works in an enterprise environment, I can't say i agree with everything you have stated, I feel you have highlighted the good and bad points to each level of RAID pretty well. I feel your statements about R/W speeds, particularly, would be better received if you were able to back it up with real world test data and not "Internet Calculators".
Each level of RAID has its use case, along with its pro's and con's which had highlighted, and i think it is important for users to understand the pro's and con's of each RAID level including SHR 1&2.
Raid 10 is is a phenomenal configuration but it no silver bullet, it has its place and its strengths but 50% loss of space to the mirror may not be acceptable in some cases. Again, this is where the "Use Case" comes into play. You chose a RAID level based on the use case and the requirements of the environment it will serve. It will always be a compromise between the four factors you opened up with, Price, Performance, Space and Redundancy/Reliability.
I agree 120% that the resilvering time on anything but R10 is obscenely long and 1-2 weeks is certainly not an exaggeration.
Other than your disdain for Synology and RAID levels other than R10 I think you did a great job!! You are a smart guy and i think you could drastically increase your viewership if you were to scale back the harsh tone and provide some actual data to back up performance statements.
Thanks for reading...

[PineapplePi]

Great video! I have never realised that there is no write performance increase with RAID5 and RAID6. Just wondering if 'write' SSD cache is added to RAID5/6, will there be any improvement for the write performance?

[KennethScottMyers]

Not sure if I'm missing something on the RAID 5 or 6 write speeds you point out, but we have several Synology's using SHR 1 and 2 (a form of RAID 5 & 6) and can easily achieve 800+MB/s. Easily enough speed for 4k video editing. Plus this gives you 1 and 2 drive redundancy. I can usually rebuild a 16TB failed drive in about 24-48 hrs with no downtime. Seems like a reasonably good solution to me.

[MrEe]

I created a single volume pool consisting of 5, 4TB drives and then tested the write performance using SHR and RAID 5. I got much better performance using SHR! So, I am not sure why you are saying SHR is crap.

[Gronvoll]

I have a Synology DS920+ with a 16 TB Ironwolf PRO hard drive in a RAID 1. I have now bought another Synology DS923+ and enough 16 TB ironwolf to fill both NAS. I was thinking of using one Synology as backup in another house. Which RAID configuration should I use when I have two Synology NAS. (and is it difficult to change RAID settings)

[AndroSpud]

Another awesome video Tim, keep up the fantastic content! Your Session and Oxen videos are great!

[dorianvocalartist]

preach brother Tim!

you’re performing a great service to the community with this down to earth tell it like it is video

thanks 👍

[robandkarenphotography]

Firstly very informative. I had to laugh because some of the videos shown i've just watched thinking these guys really know their shit. Just when you think you've got a full grasp of this type of technology I stumbled on to your video and realize this guys are just reading from the bloody box. Well again thanks. I'm new to this whole world of Raids/NAS. I'm a single photographer and video editor. I shoot photos and video with a canon R5. I currently have 20+ GBs of video and photos on different sized WD drives. Now I would like to properly organize it all. With same sizes drives. What you recommend as a proper Raid / NAS set up for someone in my position. I have a budget of $1, 500 -$2, 000.

[FiddlerOnTheRoof]

Sir, you are intense and fantastic. Thank you.

[sylvainalain]

I have the ds923+ with 2x ironwolf 12TB in raid1. I don’t plan to add any drives for a couple of years :) So shr is useless for me.