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?
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?
What if the RAID 5 gets encrypted with ransomware, how many backups are there?
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.
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.
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.
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.