Why are people even discussing the risks of RAID 0

[Silly John Fatty]

You'd assume that everyone who's thinking of going with this setup is also doing regular backups. So how come this is even something people are discussing?

From what I understand, the RAID 0 setting itself doesn't increase the technical risks of drive failure in any way. It's just the fact all your data is split that makes you lose all your data - if you lose it.

Or maybe I'm wrong and there is some additional wear on your drives, or other conditions that increase the risks of your drives failing.

But even then, you still have backups. What's the fuss about?

 

[netnewswireuser]

RAID0 doubles the failure rate b/c if 1 of the 2 drives is down you lose ALL the data.

BTW if you take backups daily and you don't care about business continuity (i.e loosing a day of work reinstalling the OS and restoring the data in case of failure is not a problem for you) then it's totally fine to use RAID0.

Now my opinion: taking into account that modern SSDs and NVMes are super fast and they usually saturate the bus that they are attached to, RAID0 will not provide you a great advantage. And in the case you are using mecanical HDDs, I would consider replacing them with SSDs instead of using RAID0.

 

[Silly John Fatty]

RAID0 doubles the failure rate b/c if 1 of the 2 drives is down you lose ALL the data.

Yes, but does it increase the failure rate for any of the drives to fail in the first place? Because the probability for that is already low, but it would be interesting to know if the RAID 0 setting increases this probability.

BTW if you take backups daily and you don't care about business continuity (i.e loosing a day of work reinstalling the OS and restoring the data in case of failure is not a problem for you) then it's totally fine to use RAID0.

I agree that if you're running a business it's a different story. I want the RAID 0 setting for my private stuff, I just want maximum speeds. And I would do backups of course.

Now my opinion: taking into account that modern SSDs and NVMes are super fast and they usually saturate the bus that they are attached to, RAID0 will not provide you a great advantage. And in the case you are using mecanical HDDs, I would consider replacing them with SSDs instead of using RAID0.

When you say "saturate", do you mean a form of damage or just that they're at their maximum speed?

If the latter: RAID 0 will provide a big advantage in my case, because I can use the entire 40 Gb/s that I can get with my Mac mini from both its Thunderbolt controllers. Otherwise it will be only at around half of that.

Right now I'm using a mix of HDDs and SATA SSDs. I'm planing to move to NVMe SSDs in RAID 0 and use HDDs for backups. Best plan I've come up with so far, but I might find better yet.

 

[LeeW]

RAID0 doubles the failure rate b/c if 1 of the 2 drives is down you lose ALL the data.

Like almost every PC and Laptop everywhere in the world today which has only 1 drive. No different. Not a doubling of failure rate when only 1 failure results in total loss.

From what I understand, the RAID 0 setting itself doesn't increase the technical risks of drive failure in any way. It's just the fact all your data is split that makes you lose all your data - if you lose it.

Yes, pretty much. There is an increased chance albeit very slight of data corruption but in my 20+ years of managing servers in data centres, the chances are <0.1%. RAID0 itself does not cause wear in any different way than having just 1 or 4 in RAID10.

But even then, you still have backups. What's the fuss about?

You would be surprised how many servers I see being run in RAID0 with no backups. It takes a failure to adjust many people's attitudes to backups.

 

[netnewswireuser]

Yes, but does it increase the failure rate for any of the drives to fail in the first place? Because the probability for that is already low, but it would be interesting to know if the RAID 0 setting increases this probability.

Not for each individual drive but YES for the data. Your data is more prone to failure b/c it depends on 2 drives instead of one.

When you say "saturate", do you mean a form of damage or just that they're at their maximum speed?

If the latter: RAID 0 will provide a big advantage in my case, because I can use the entire 40 Gb/s that I can get with my Mac mini from both its Thunderbolt controllers. Otherwise it will be only at around half of that.

Right now I'm using a mix of HDDs and SATA SSDs. I'm planing to move to NVMe SSDs in RAID 0 and use HDDs for backups. Best plan I've come up with so far, but I might find better yet.

No damage. If the maximum speed of your fastest drive is equal to the bus speed then you will not get a huge speed improvement if you go RAID0.

If you plan to go NVMe connected through Thunderbolt, depending on the enclosure and/or the RAID software that you plan to use, the RAID0 could be beneficial or not . I need more details.

 

[Silly John Fatty]

Like almost every PC and Laptop everywhere in the world today which has only 1 drive. No different. Not a doubling of failure rate when only 1 failure results in total loss.



Yes, pretty much. There is an increased chance albeit very slight of data corruption but in my 20+ years of managing servers in data centres, the chances are <0.1%. RAID0 itself does not cause wear in any different way than having just 1 or 4 in RAID10.



You would be surprised how many servers I see being run in RAID0 with no backups. It takes a failure to adjust many people's attitudes to backups.

Thanks for your valuable input!

Not for each individual drive but YES for the data. Your data is more prone to failure b/c it depends of 2 drives instead of one.

Seen like this, yes. But I'm planing to do regular backups anyway.

No damage. If the maximum speed of your fastest drive is equal to the bus speed then you will not get a huge speed improvement if you go RAID0.

If you plan to go NVMe connected through Thunderbolt, depending on the enclosure and/or the RAID software that you plan to use, the RAID0 could be beneficial or not . I need more details.

In my case there will be one, I'm sure about it. Almost twice the speed. Many people have the setup I'm looking for.

 

[marzer]

You'd assume that everyone who's thinking of going with this setup is also doing regular backups. So how come this is even something people are discussing?

From what I understand, the RAID 0 setting itself doesn't increase the technical risks of drive failure in any way. It's just the fact all your data is split that makes you lose all your data - if you lose it.

Or maybe I'm wrong and there is some additional wear on your drives, or other conditions that increase the risks of your drives failing.

But even then, you still have backups. What's the fuss about?

No, you are correct. Using drives in a RAID0 configuration does not increase risk of technical failure. As a network engineer, I‘ve seen this issue argued for decades by people who don’t understand the math or nature of the devices. And I have personally and professionally used RAID0 systems that often lasted no less a life span than one would expect from a single storage device.

Yes, all primary storage devices (HDD, SDD,NVME, ETC.) should be backed up, therefore failure rate is moot.

There are many professional needs for storage speeds beyond a single device, even NVME. Check out Linus Tech videos, he covers some very high end professional RAID systems. As a gadget guy I ran RAID0 for years on my home network, including NVME in a Mac Pro.

That aside, there are ways to calculate failure rate based on the array size. In its simplest form, a RAID0 storage can be expected to last as long as the weakest drive in the array. Of course, if that same drive were a standalone storage device, it would fail just the same. To put it in simple math, if drive A is MTBF of X and drive B is MTBF of Y, MTBF of RAID0(A+B) could be roughly estimated as (X+Y)/2.

Do a search on Macrumor forums, a few years ago a member demonstrated more precise statistical calculations. Many data warehouses have also published studies on their experiences with drive failures.

 

[Basic75]

Yes, all primary storage devices (HDD, SDD, NVMe, etc.) should be backed up, therefore failure rate is moot.

This! Nobody should think that they don't need to back up just because they are using RAID5 or 6.

 

[Basic75]

To put it in simple math, if drive A is MTBF of X and drive B is MTBF of Y, MTBF of RAID0(A+B) could be roughly estimated as (X+Y)/2.

Is that assuming independence of failure? And what distribution function of failure over time for a single drive?

 

[marzer]

Is that assuming independence of failure? And what distribution function of failure over time for a single drive?

Exactly! The nuance to the math to accurately profile failure rate is much more involved than the simple averaging I demonstrated. The more precise the statistical analysis, the higher the reliability one may discover. All above my pay grade (despite having *barely* passed quantitative analysis in my graduate studies), that’s why I would recommend researching the related discussions that occurred elsewhere on this forum.