Best NAS RAID Mode level?

Deleted member 952 · Mar 13, 2022

Did some research and it seems my nas does not support BTRFS so I upgraded to the DS 720+ and now I'm using 16TB on a SHR with BTRFS and it runs amazingly also got a UPS for extra backup power wise, in-case I get a powercut.

Kencarter77 · Oct 7, 2022

As per the your requirement the best RAID Mode will be 5 or 6.
RAID5 is an ideal combination of price, speed and quality.
RAID5 is almost identical to RAID4, however, it doesn't write the parity information onto a separate disk and rather evenly spreads it over all disks. This means that RAID5 can resist the failure of one disk without losing data and access to it, because the data and the parity information located on the disks serve to recover the lost blocks.

While RAID 6 is similar to RAID5 with one difference – a double Reed-Solomon code, which is written onto two disks, is used instead of the parity information. Therefore, the minimum number of disks rises up to four and the system may continue working even in the case of the loss of two disks.

pparks1 · Oct 7, 2022

Kencarter77 said:
As per the your requirement the best RAID Mode will be 5 or 6.
RAID5 is an ideal combination of price, speed and quality.

Problem is, RAID 5 requires a minimum of 3 drives. The NAS being used is a 2 drive unit.

pparks1 · Oct 7, 2022

jimbo45 said:
Even on a NAS you should still backup its data regularly -- you don't have to back the entire thing up daily but either do differential / incremental or backup specific directories at regular intervals.

ABSOLUTELY.

Raid is not a backup. A Raid 1 mirror may seem like a backup, but if you were to get ransomeware it just means you now have 2 copies of the same locked file. Or if you accidentally overwrite an important file, it overwrites it in both places immediately. So. It is definitely not a backup.

Primary use of Raid 1 is the boot drive for a server. In the event 1 drive dies, the server can still boot. That's all. It's redundancy of hardware. It's not a backup.

If you only get 1 thing from this post, it should be Raid is NOT a Backup.

rpetruzz · Oct 7, 2022

@kuyenmotdivad

The original poster asked about Synology's SHR Raid. SHR is different from Classic Raid which all of the other posters have addressed. It is not similar to Raid 1 but rather is, according to Synology's site, is based around a Linux Raid Management system. I have a DS1019 with 5 4tb drives that have been running SHR Raid for the past 3 years without a single problem. But it is not classic Raid 0, 1, 5, 6 etc. I started with 4 4tb drives and a year later added the 5th 4tb drive and all I did was insert the drive and power back up. No fuss, no muss. As a simple home owner this made life so easy.

What is Synology Hybrid RAID (SHR)? - Synology Knowledge Center

Synology Knowledge Center provides you with answers to frequently asked questions, troubleshooting steps, software tutorials, and all the technical documentation you may need.

kb.synology.com

Kencarter77 · Oct 19, 2022

With a SHR RAID, you will only lose 1x the largest drive in terms of redundancy vs. capacity, regardless of how the drives are mixed. In contrast, if you mix discs in a RAID 5, ALL of them will be seen and RAIDed as the smallest available drive, and you will still only have a single drive's worth of redundancy.

SHR, as contrast to standard RAID, creates additional redundant storage by breaking up each drive's storage space into smaller portions. Using the same example as before, SHR is able to increase the storage capacity of each disc by dividing the 4.5 TB of unavailable storage into smaller accessible bits.

If you are looking for the best RAID for Synology, then you should go for the RAID 5 because,
It successfully balances performance and redundancy. A single drive is locked away to retain all the essential data to reconstruct a storage medium in the event of a failure, with a minimum of three drives required.

jimbo45 · Oct 19, 2022

If you backup stuff regularly RAID 0 is fine since on most decent software systems you can aggregate the TOTAL amount of HDD space rather than just match the smallest HDD in mirroring systems. Speed can be very good indeed. HDD's are really so much more reliable than before so the chances of losing the array is very small. IMO if you don't need to run critical stuff 24/7 the risk of using RAID 0 IMO is well worth it. I haven't had an array failure in over 5 years and the only time my NAS server gets shut down is to upgrade the hardware or sometimes update the OS.

But if you DO use RAID 0 aways have backup since if it DOES fail you have to re-build the entire array.

It's simply a case of risk to reward ratio and only you can do that.

I'm probably in a minority of 1 here but being able to use oddball sizes of HDD's efficiently is well worth it IMO.

Cheers
jimbo

veldthui · Nov 2, 2022

jimbo45 said:
However disadvantage is that with RAID 0 - if you lose any disk within the array you lose the lot. My experience is though that decent HDD's are robust and reliable and breakdowns are actually quite rare these days. The speed improvement in RAID 0 plus the convenience of being able to "Mix HDD sizes" to get the maximum storage IMO is worth it. -- Make sure though you back up data in case you need to re-build the array.

Would not go with that. I have lost 3 drives over the last 12 months, two of which were still in their warrantee period and replaced free (not the data of course). They were all good named drives and supposedly NAS labelled. Having them in RAID 5 though I simply replaced the drive and got it to rebuild.
RAID doesn't always save you though. I had my Synology NAS MB fail. Everything appeared to be working but it continually reported disk errors and then would not longer access them. It had corrupted 8TB of data but as it was backed up to another NAS so no lose. Remember RAID is not a backup solution.
I always use RAID1,5, or 6. On the Synology NAS I use the SHR and it's file system as more robust.

Kencarter77 · Nov 29, 2022

RAID 1 — I believe the issue here is that mirrored drives need to be the same size. Thus you would have one 1 TB disc that is mirrored and the other one that is —???? Since Windows lacks a true "Native" software RAID system, it is probably useless, especially if the HDDs are connected to a hardware RAID card.

When testing or requiring the fastest possible IO, RAID 0 is fantastic. Moreover, you lose everything if any drive in that array fails. To safeguard your data, you should always have a frequent backups.

Cheers

jimbo45 · Dec 2, 2022

Kencarter77 said:
RAID 1 — I believe the issue here is that mirrored drives need to be the same size. Thus you would have one 1 TB disc that is mirrored and the other one that is —???? Since Windows lacks a true "Native" software RAID system, it is probably useless, especially if the HDDs are connected to a hardware RAID card.

When testing or requiring the fastest possible IO, RAID 0 is fantastic. Moreover, you lose everything if any drive in that array fails. To safeguard your data, you should always have a frequent backups.

Cheers

Whatever system you choose you should always have adequate backup.

I've been running RAID 0 though for several years without any issues -- on a lot of systems RAID 0 arrays can be composed of HDD's having unequal capacity so can use odd HDD's you might have from discarding or upgrading older hardware.

I suppose the whole thing is on the quality of the HDD's in the first place -- I'm using TOSHIBA NAS enterprise quality drives which are designed for prolonged use and running at 24/7.

Like all these things -- Risk to reward ratio. If I did have to re-build an array I can easily run this as an overnight job - I'm not running essential e-commerce or web sites for a load of users.

On Windows though there's no decent software raid option -- Storage spaces are your only option there and I've had a lot of bad experience with that from W7 onwards so I stick well away from it these days. I simply run Linux with mdadm (software RAID) on my main NAS - and if I'm testing Windows server 2022 on a physical machine I run a Linux VM on it with a 4 bay HDD external enclosure running RAID 0 which serves any remote Windows users.

Again "You pays your money and takes your choice".

Remember also that some types of RAID allow dynamic / hot swapping of HDD's which could be of interest to some--- my hardware though doesn't allow HDD Hot swapping.

Cheers
jimbo

Berton · Dec 2, 2022

I've had a 2TB NAS drive [WD MyCloud] for about 7 years and am replacing it because the software for it has a security issue and not been updated and newer is not available. I just installed a Buffalo NAS 2-bay that came with 2 x 2TB drives set for RAID 1/Mirroring, been copying with Total Commander without a hiccup. I could have changed to RAID 0/Striping for 4TB but the downside is if one drive fails all the data is lost.

EDIT: I had copied this from What is RAID 0 | Advantages/Disadvantages | Ontrack but it didn't get included:

Comparison between RAID 0, RAID 1 and RAID 5.

While RAID 0 focuses on distributing tape data to speed up file processing, RAID 1 mirrors two or more hard drives to secure the data. Each inscribed byte is therefore duplicated, so in case of failure, the data is not corrupted. No performance gain is achieved and you lose 50% of the storage capacity. But, this is the most secure type of RAID.
The RAID 5 was created to gain security while maintaining performance. Therefore, the technique of distribution of data by tape or striping is maintained, but parity bits are arranged regularly on all disks. In the event of a disk failure, these parity bits make it possible to recover the data bits. Read performance is assured, but writing parity bits slows data burning on hard drive tracks. It takes at least three hard drives to build a RAID 5.

jimbo45 · Dec 2, 2022

Hi folks

I've never had a problem with RAID 0 -- although again I keep saying "Risk to Reward" ratio. Speed even on slower devices is usually fantastic and the advantage of being able to mix devices with different "Geometries" and capacities on many decent software RAID systems is well worth it.

Even if I have to re-build a 15 TB Raid 0 array it's easily recoverable from an overnight restore -- and I've only had to do it one time in over 6 years running a NAS 24/7. The trick as I keep saying is to use high quality Enterprise grade HDD's.

Many firms / offices are chucking out really good kit as they move to cloud servers -- I've rescued another 3 X 14 TB Toshiba NAS enterprise grade HDD's from a one way visit to the tip (recycling centre!!) from businesses moving / upgrading servers -- and usually they give me these saying -- if you can take the rest of the junk --it's "On the House".

So very useful to back up the RAID 0 arrays to one of these via a powered external USB->SATA connector. For the 3.5 ins disk you will need a powered connector.

Here's one of my NAS's storage config : On this one 2 old HDD's in a 7.3 TB RAID 0 NAS array .
My more modern one (not logged on to concurrently) has 2 Raid 0 arrays of 12 TB each.

Those 14TB HDD's I rescued from "The Tip" are sufficient for backup. Things like multi-media / ripped CD's etc don't change much so doing a backup doesn't need a huge amount of extra space after the initial one.

They are marked as "Internal" because they are simply connected easily to the 4 bay HDD system on the server. Can be easily removed by just opening the door on the server (after power down) and unplugging. No tools whatever needed. Then they can be connected to other NAS via the USB->SATA connector and able to store / restore backups etc.

For Linux users --consider using rsync and as a GUI grsync. Really easy for decent backups.
GRSYNC :

Many options -- makes windows robocopy look like an abacus compared with a "quantum comuter" or an old pre Berlin wall fall East German Trabant car compared to a modern Ferrari etc.

Have fun with this :

The Worst Car Ever: A Brief History of the Trabant | Jon Miltimore

It is the car that “gave Communism a bad name,” a vehicle so inferior to automobiles produced in Europe and America that few could deny the system’s failings. It became, in short, a joke.

fee.org