Why do people say "Raid won't prevent data loss"...

I am also in Japan (100M up/down :-D), where are you at that you don't get that much bandwidth. I've gone to Ofunato (tsunami zone) and they still have like 60M there.

Also agree with the idea that RAID is to maintain uptime. Backups are more about the data itself.
 
Nothing can truly prevent data loss other than preparation. Someone above in thread stated "any data you don't have two or more copies of is data you don't care about" which is quite true.

I describe RAID arrays to my customers by telling them that RAID provides fault tolerance and redundancy, not a way to prevent data loss. It provides more uptime and performance in some use cases. This has been said previously in the thread as well.

It is still surprising how much this is discussed in even a Fortune 500-level enterprise environment. Not a week goes by where I have to ask people (that should know better!) about backups. There is never a situation that you should not back up your data you would prefer not to lose. Backup, backup, backup.

My parents run a small but prolific vending business that really has minimal data that cannot afford to be lost, but what is there is crucial, such as tax information and sales numbers. I set them up a simple "backup solution" that includes a local copy on the workstation, an external hard drive for local archival, monthly backups that are stored in a safe deposit box, a yearly dump copy that is kept by their accountant, and a subscription to Carbonite. Sure, it's maybe a bit overkill for their uses, but the entire solution costs less than $1000 including multiple years of Carbonite. RAID doesn't factor in for obvious reasons since they don't require high availability. Preparation is the only way to prevent data loss.
 
Would a 2-drive RAID1 with a Synology NAS as "backup" storage count as backup? You'd have 2 copies of original data . . . :?
 
Cerulean said:
Would a 2-drive RAID1 with a Synology NAS as "backup" storage count as backup? You'd have 2 copies of original data . . . :?
Click to expand...

Yes you would have 2 copies....

Until a PSU took out both drives.....

Then you would have none

;)
.
 
I live on a military base. Gigabit connection speeds are literally 200ft from my window. The way the internet is ran on base by the company that has the contract is borderline illegal and they violate various areas of their contract. $150 on base gets you an advertised 20mbit connection with actual speeds of 1-1.5mbit and terrible latency with a 150gb cap.
 
Tengis said:
I live on a military base. Gigabit connection speeds are literally 200ft from my window. The way the internet is ran on base by the company that has the contract is borderline illegal and they violate various areas of their contract. $150 on base gets you an advertised 20mbit connection with actual speeds of 1-1.5mbit and terrible latency with a 150gb cap.
Click to expand...

It's been like that since the days of dial-up. I lived in a military base in Japan during the 90's, I had a 56k modem but only got 28k speeds because that was the most the base lines could support. Download speeds never went above 5 KB/s. Just outside the base the Japanese were using the "new" ISDN technology and some were trying out the "experimental" cable internet. Fast forward more than 20 years later and Japan still has faster internet than the USA.
 
The base actually has had "upgraded" equipment for a while. They offer gigabit internet connections in some of the towers on base but the speeds usually test at around 200mbps or a little less. The cost is... insane. Over $180 for "gigabit" internet with 300gb data cap.

Right outside the base you can get a true 200mbps or faster for about $50 with no data limit. The internet provider on base does all kinds of bandwidth throttling based on time of day and what you are using your internet connection for. They throttle it down super slow at night (unofficially) to prevent illegal file sharing. They have broken and stretched a lot of the "rules" in their contract but either nobody cares on base (Aafes) or they are too busy having their pockets lined with cashola.
 
Cerulean said:
Would a 2-drive RAID1 with a Synology NAS as "backup" storage count as backup? You'd have 2 copies of original data . . . :?
Click to expand...

No you do not have two copies. Whatever action is applied to one is immediately applied to the other. RAID is not backup which has been said over and over it only protects data loss for one case of the many many ways your data can go away. I don't care what hardware you put that copy on, disk, magnetic, hole punch, monks transcribing it to scrolls (unless you have 2 monks) you need it two separate copies of the data.

You also missed the part in my post about proper backups actually do incremental backups. Just copying data to another location that you overwrite EVERY TIME is not a good backup, it is better than nothing but is still unsafe in my world since it would not protect against corrupted data that went unnoticed for a single backup cycle. Corrupted data happens more than fully failed harddrive since it can happen from user error (deleting a file, overwriting a file, virus, etc.)
 
I never say that. I do sometimes say "RAID will not prevent you from loosing data".

Really, loose data can be a serious problem. You should always lock the door or use a leash. :D
 
Tengis said:
I thought that was the entire point of raid... so if you have a drive failure your data is still safe.

In my eyes it goes something like this for my own personal nas: Drive dies, unplug nas, acquire drive/pull extra out of closet, rebuild raid... safe data!
Click to expand...

That IS the point of RAID. The people that say things like that are trying to be correct but usually don't explain it well enough.

RAID decreases the possibility of data loss. Technically it's correct to say "it doesn't [totally] prevent data loss," but in the same sense, backups also are not perfect as the media can also become corrupted. It happened with some tapes at a company I worked for before.

What these people mean to say is that RAID isn't perfect, and that it doesn't replace backups, at least not if your data is important to you. But also understand that backups are not perfect, either. Depending on how important your data is, you design a strategy around it. It is no more correct to say that you need backups than to say you should or shouldn't rely on RAID. It all depends on the specific use case.

But keep in mind RAID doesn't prevent filesystem corruption (I've had this happen so many times with NTFS - NTFS is old and really shitty) or user error. Those are the main reasons people still recommend backups. Again, whether you need more than RAID depends on your specific use case.
 
Last edited:
Jim G said:
Some viruses can encrypt data on network attached storage devices and I'm pretty sure most people have - at least once - accidentally deleted a file that they had permissions for but didn't want gone.
Click to expand...
Had this happen on a shared file server. Some idiot (a supervisor with elevated access) somehow managed to get a ransomeware to run. Thank goodness for backups!
 
You must log in or register to reply here.
Back
Top