Me and my friend were discussing this the other day about how he said RAID is no longer needed. He said it was due to how big SSDs have gotten and that apparently you can replace sectors within them if a problem occurs which is why having an array is not needed.
I replied with the fact that arrays allow for redundancy that create a faster uptime if there are issues and drive needs to be replaced. And depending on what you are doing, that is more valuable than just doing the new thing. Especially because RAID allows redundancy that can replicate lost data if needed depending on the configuration.
What do you all think?
due to how big SSDs have gotten and that apparently you can replace sectors within them if a problem occurs
True, but that’s something an SSD does internally and is just there to prolong the lifespan.
You definitely still want a raid if you want to keep a system running during a disk failure. No amount of extra sectors and wear leveling will safe you from that
yeah but if SSD failing is now less likely that other parts of the machine it might be better to focus on a redundant server to fail over to… it’s an interesting thought. RAID isn’t obsolete I don’t think but it’s an interesting question
Hmm but in a server enviroment wouldnt it be possible for ssd to reach their wear level much faster and therefor fail due to that ( depending on the workload of course ).
Higher end Samsung ssds were dying a lot faster than they should. I dont know what drugs your friend is on thinking they cant fail but theyd better have enough for the rest of the class.
Reminds me of the days that cdroms were brand new and advertised like indestructible, with photos of elephants walking over it. Having said that I assume SSD disks can break like other hard disks can break, and in that case RAID can save a lot of time to get a computer back up especially when a lot of data is involved.
Funny. Growing up, I was taught to be extra careful with CDs because the moment you look at them wrong, all your data gets corrupted.
Had a microsd card literally break in half last week. They’re definitely not invincible
Was that a SteamDeck? 🙃
3ds
Ok. Coz it is really common for SteamD users to forget removing SD card when didassembling device. Lots of cards have been lost
Yeah they sometimes get touted as that
…absolutely, positively, super false. I work in a sector where we’re constantly dealing with huge capacity enterprise SSDs - 15 and 30 terabytes at times. Always using RAID. It’s not even a question. Not only can you have controller malfunctions, but even though you’ve got what’s known as “over provisioning” on the SSDs, you still need to watch out for total disk failures!
SSDs still have component bottlenecks that can kill the whole drive, same as hard drives.
Also, 3-2-1 is far superior to RAID, but having RAID on top of that is nice.
- Maintain three copies of your data: This includes the original data and at least two copies.
- Use two different types of media for storage: Store your data on two distinct forms of media to enhance redundancy.
- Keep at least one copy off-site: To ensure data safety, have one backup copy stored in an off-site location, separate from your primary data and on-site backups. https://www.veeam.com/blog/321-backup-rule.html
3-2-1 is for backup, RAID is also for availability, eg your domain server not going down in case of drive failure. good point though.
People say RAID isn’t backup, but I’ve never understood that. Yes it’s only one medium and it’s probably not off-site, but if you’ve got an off-site copy in a different medium, why doesn’t a single RAID 5 count as 2 copies of your data to add up to get the 3 in 321 backup?
Suppose you’re hit by a ransomware attack and all the data on your NAS gets encrypted. Your RAID “backup” is just as inaccessible as everything else. So it’s not a backup. A true backup would let you recover from the ransomware attack once you have identified and removed the malware that allowed the attack.
I really, really liked @atimehoodie@lemmy.ml’s answer, because even as I was reading it, I was thinking of things that they could have said—but didn’t—which would have been easily rebutted. Those things fell into two basic categories: malware, and environmental effects.
As I understand it, malware is an issue with any online backup system, whether that’s a RAID or just a second external hard drive. So I don’t really think it works as an answer to why RAIDs specifically don’t qualify as backup.
Media failure isn’t the only reason to back up. If you delete a file on a RAID array, it’s gone on all disks. If you need to recover that deleted file, you can’t recover from RAID. The same goes for formatting/damage of the file system, recovery from something wrong inside a database, etc.
What if the RAID 5 gets encrypted with ransomware, how many backups are there?
RAID is resiliency, but not a backup. It doesnt hold a previous dates version, it doesn’t protect against accidental deletion. Nor does it protect against changes to files.
Many causes of data loss affect all RAID drives equally from accidental deletion over power surges, fire, water damage, theft,…
I really, really liked @atimehoodie@lemmy.ml’s answer, because even as I was reading it, I was thinking of things that they could have said—but didn’t—which would have been easily rebutted. Those things fell into two basic categories: malware, and environmental effects.
Environmental effects like water damage and theft are a problem for any local storage, regardless of the technology. If it’s a RAID, or an external USB drive, or even a NAS in your closet. The power surge is probably the best example of RAID not being backup, since it’s very possible that one device might receive the surge but not the other, if they’re connected to different outlets. But as for the other ones? Eh, I don’t really buy it.
I have literally lost all data on a RAID6 of 12 drives since the power distributor in the server (the bit between the redundant PSUs and the rest of the system) got fried and took 5 out of the 12 drives with it.
you can replace sectors within them if a problem occurs
That won’t help you if sector where your data is located dies!
I do recall google apparently stopped using raid in some data centres, but it was because they had whole-machine redundancy.
RAID is probably redundant for some of the uses it used to have, like optimising read performance by using many drives (SSD is fast) and honestly I suspect that SSDs are probably more reliable as they don’t have a bunch of platters and bearings and screaming rotational speeds.
So if you needed it for a base level of reliability, an SSD on its own may have exceeded that.
I suspect there are still uses for drive redundancy in some high availability setups… although your friend might be right. If the likelihood of drive failure is lower than other parts in the machine and you need high redundancy for availability it might make more sense to replicate the whole machine rather than the drives.
It’s possible redundancy specifically for the drives was an artifact of unreliable drives back in the day 🤔 they might have a point! I think it’s likely still useful at times though.
I’d rather hotswap a drive than set up a new server, even if it’s a less likely scenario.
Raid often comes with snapshots which can recover from your mistakes. Often the raid can even recover after malware encryhts your disk. you still need offline, offsite backups for the best protection but raid is still a useful part of your data safe
I’d say “old” RAID could be dead if you have proper backups and have the ability to replace a defect drive fast in the case uptime is crucial. But there’s also modern RAID like btrfs and zfs that also can repair corrupted filed, caused by bitrot for example. Old RAID can’t do that also hardware based RAID couldn’t either when I used it until years ago. Maybe that changed but I don’t see the point of hardware based RAID in most cases anymore
I’d say “old” RAID could be dead if you have proper backups and have the ability to replace a defect drive fast in the case uptime is crucial.
RAID and backups serve different purposes. Backups are to prevent data loss, RAID is to prevent downtime in case of hardware failure. They are not interchangeable.
Hardware raid can 100% do any of the above tasks, and has always been able to do them. You need an actual raid card, not some half assed baked in mobo raid.
Hardware RAID was doing all of the above before software RAID was available to end users.
I wonder how to detect real raid card from simple switch? I guess to look at price and it should be really high?
Most discrete raid cards will do the job, but look for on card caching and a battery for “quality.”
AFAIK only officially supported RAID modes in BTRFS are RAID0 and RAID1.
RAID56 is officially considered unstable.
Raid56 is a risky one in more filesystem than just btrfd though, but if you have a ups as backup, you should be fine.
UPS won’t protect from Kernel Panic, sadly
This is a total load of bullshit, your friend is wrong
its not about the individual drive… its about total drive failure… if that ssd’s controller dies it doesnt matter if it has extra data sectors.
that said, I moved on from raid by mirroring multiple , unraided NAS devices for redundancy with data stored specifically on the drives in such a way as to eliminate cross disk logical volumes.
He said it was due to how big SSDs have gotten and that apparently you can replace sectors within them if a problem occurs which is why having an array is not needed.
Buying SSDs with the same capacity as my NAS with 70TB (after raid 6) would cost almost tripple of what my setup (including the NAS) costs.
So unless you shit money, SSDs are not an option for anything with a decent capacity.
- Bit rot is still a problem, you need a high integrity file system and or RAID to avoid that
- Full drive failure is still about as likely, IE the main reason for RAID of multiple drives in the first place.
A good read on the problems with SSDs SSD 101: How Reliable are SSDs?
I found this article from the one you posted. It is crazy think DNA can be used for storage one day.
SSDs man, I personally still don’t trust them for primary storage. My data array is unraid, several spinning disks. Spinners just always work for me, there are gotchas of being jostled or turned off incorrectly, but if you treat them well they’ll last a real long time. Plus the double redundancy of my array and I’m very happy with it. (Plus I don’t see 20TB ssds on the market for 300 bucks either).
SSDs though wear out, they only have so many IOPS in them. I had some in a traditional raid and it just ate through them. Too many writes and I had 5/6 fail on me. I use them now as cache drives, for unraid you can set a faster drive to store data temporarily, and then it will move it off the cache drive later onto the main array, and that’s a level of risk I’m happy with.
Is your friend going to pay for enough SSD’s for me to store my 60 TB of data?
