kek, i just found this reading about raid1 on wiki
>In practice, the drives are often the same age (with similar wear) and subject to the same environment. Since many drive failures are due to mechanical issues (which are more likely on older drives), this violates the assumptions of independent, identical rate of failure amongst drives; failures are in fact statistically correlated.[11] In practice, the chances for a second failure before the first has been recovered (causing data loss) are higher than the chances for random failures. In a study of about 100,000 drives, the probability of two drives in the same cluster failing within one hour was four times larger than predicted by the exponential statistical distribution—which characterizes processes in which events occur continuously and independently at a constant average rate. The probability of two failures in the same 10-hour period was twice as large as predicted by an exponential distribution
tldr two identical drives in raid can break in the same hour.
im basically in this scenario, should i worry? anyone was there?
>>51695616
Very unlikely, typically this kind of thing would happen if you are working in a datacenter with hundreds of RAID volumes.
Either way, know that RAID is not a replacement for backups and your most important files should always be backed up.
>>51695616
Statistics isn't science.
>>51695616
Raid 6
>>51695639
>RAID is not a replacement for backups
that is the biggest mental problem i have, i dont like storing multiple copies, thats why i created raid, to feel safer, no stare any duplicates and still use it daily
Probably not. The chance is still rather slim.
You shouldn't worry - as long as you make backups. Raid does not replace backups.
>>51695639
>very unlikely
WRONG. you failed to fundamentally understand the material in the green text.
holy shit, it gets even worse as i read more
>Unrecoverable read errors during rebuild
>Increasing rebuild time and failure probability
>Atomicity: including parity inconsistency due to system crashes
i have personal photos (4-5GB) backing this up somewhere.
funny thing is every huge hdd i have is now part of raid
>>51695616
You don't have a spare disk anon ?
And if you are worried, then just shut down your PC and go for some new HDD.
>>51695752
Keeping one copy of any important file is a bad idea
>>51695616
>100,000 drives
>the probability of two drives in the same cluster failing within one hour was four times larger than predicted
>four times larger than predicted
now question is what was this predicted number
RAID 1 is not good for normal backups
Raid 1 is for a scenario like this
>be sysadmin
>have a server, two drives
>users constantly upload and download from it, changes every second
>data on there is absolutely vital
>setup a raid 1 array, if one disk somehow fails, the other is there to instantly replace, no work required due to a mirror
However if a malicious user or otherwise gets into the drive and runs rm -rf /, you can say goodbye to both.
Just keep your important files on a second HDD
>>51695616
>failing within one hour
Fucking hell, I never thought it was this bad.
BRB, shuffling all my drives.
>>51695871
>shuffling drives
>they fail to rebuild
wish you luck m8
>>51695616
This is why RAID is completely pointless it's all just a dice roll anyway.
And is anyone really stupid enough to build their entire RAID array out of seagates?
>>51695616
RAID is not a backup.
>>51695964
>Raid is pointless
>I don't run servers that chew through a couple drives every other year.
>I don't know what HA is.
Ok, kid.
The same disks are indeed more likely to fail in relatively short time frame. This is something you shouldn't be alarmed by when using proper backups, and not just a RAID configuration.
no, because the chances of that happening are astronomically small
>>51695964
i did this, 2x2tb seagate, cant remember model, working for now, lets not go in whats wrong with seagate, better say whats better for storing data
Multiple failures on one array in the same week have occurred where I've worked, because the drives are manufactures with such precision. Maybe if the RAID controller would throw up a warning before 1000 sector reallocations, it could have been prevented. I had nothing to do with it. I wasn't even allowed in the server closet.
>>51695964
>And is anyone really stupid enough to build their entire RAID array out of seagates?
Yes.
>>51696081
Nothing was lost though. Nightly backups to tape.
so are pendrives reliable for backups? lets say i fill it once and dig it underground for 10 years, will it survive?
>>51696120
3 copies
2 mediums
1 offsite
>>51696138
wat
>>51696120
People say they last around 10 years.
Who knows because HDD, SSD, and flash drives will lose their data over time if unpowered.
So if you threw one in a safety deposit box for 30 years unpowered, the data would be gone.
>>51696120
Typically. But you're screwed if it doesn't hold any charge over such a long time span.
>>51696141
He means at least 3 copies, stored on at least 2 different mediums, of which one such copy is stored elsewhere off-site.
>>51696183
shit, then i have no other choice
>>51696183
>>>51696120
>HDD, SSD, and flash drives will lose their data over time if unpowered.
Doesn't apply to HDDs, only to flash memory.
Your best bet is to carve the data into stone tablets
>>51696216
yes it also applies to HDD. nice try though, really.
>>51696196
yeah those probably last less than 10 years if i just had to guess.
>>51696241
I don't think an HDD needs to hold a charge to retain its data. Your data is simply stored on the platters.
>>51696278
well that's your problem, you don't think.
all magnetic data deteriorates over time.
also good luck getting a 20+ year old hard drive to actually spin up. enjoy paying thousands of dollars for data recovery and hope it's still there.
>mfw have a raid
>mfw its not connected to any email
>mfw i just occasionally (twice a month) check if its working
im scared to check it now, i really should put email to mdadm, shit could be dead for weeks and i would not even notice it
>>51696300
>well that's your problem, you don't think.
Uncalled for.
>all magnetic data deteriorates over time.
Everything deteriorates over time. HDDs don't need to hold a charge as flash memory requires.
>also good luck getting a 20+ year old hard drive to actually spin up. enjoy paying thousands of dollars for data recovery and hope it's still there.
Wild assumption thinking this applies to me.
>>51695652
Lol I bet you don't belive in anything
>>51695616
Did you not read the text? This means that:
X=risk of failure for one disc per unit of time
Risk of two drives failing within one hour =x*(x/4)
So still 250000 times less likely than just a single drive failing or so
>>51696368
how did you get number 250000 from 100000 samples? what were you even calculating? your math is retarded, just tell me how much from these 100000 failed withing 1 hour
>>51695964
Linus did.
Tells you everything you need to know about taking his advice on literally anything.
>>51696445
thanks god linus is the good guy
>>51695676
RAID is only for hardware malfunctions. Your data could get fucked in some other way (ransomware, accidental deletion etc) and RAID would just make sure that the corrupt data is safely stored on two drives
>>51695676
>dont like storing multiple copies, thats why i created raid
You're literally copying every single bit to another drive with RAID1. Fucking hell if you did incremental backups you'd have space leftover for MULTIPLE versions of every file on your system. RAID is not and will never be a backup solution.
>>51695964
I've got 2 seagates in raid 0.
>>51696476
yeah, i already know thanks to this thread, still separate backups taste so salty to me
>>51696507
Because you read shitty advice given by people who don't know what they're talking about. It's the same sort of idiots who think keeping their RAM usage as low as possible is a good thing.
>>51696300
I got a 15 year old 60gb 4200rpm? Hard drive in my old laptop. Worked fine after being inactive for 10 years or so.
>>51695616
So you're telling me there's no reason NOT to RAID0?
>>51696520
thats a mental problem i have, putting 2 copies of 20GB twice on 1TB drive is a waste of space, but having 2x2TB raid is completely fine for me, i should seek help
>>51695616
Extremely unlikely but I've seen two drives in the same manufacturing date fail in the same week.
Don't loose sleep over it. I mean you have an backup, right?
>>51696416
It's just an example. Just explaining how the rates relate to each other. I'm wrong though it's x*(x*4) of course.
If a hdd has a 10% failure rate per year, 0.001% per hour.
Then the risk of both failing if you don't replace the broken hdd within one hour is
0.000000004% as opposed to the assumed 0.00000001%
250000 is just a guesstimate.
Tldr: raid is still many thousand times as safe as a single hdd
>>51696546
You're forgetting that when your drive fills up then the oldest revisions are deleted. Why would you ever want your backup drive/s to not be used to their fullest?
>>51696545
raid0 has nothing to do with this thread
>>51696587
Not him but I think his logic is that if both drives will fail around the same time then you might as well use RAID0 over a single drive.
>>51696585
because i feel like i could use this space for something else
Learn to read OP its saying two drives operating in the same environment are more likely to last the same amount of time because environment is the driving force behind failure. Raid has nothing to do with it.
>>51696608
but you dont store raid drives in separate cases, do you? they are probably in the same environment, in the same case, sitting next to each other
so whats the best place to store backup? external drive, another separate raid1?
>>51696523
>60 GB HDDs
>15 years ago.
We're getting old. :(
>>51695652
You're right it's math. Good job family
>>51696716
We are :(
I remember my desktop running off a single 40gb hard drive.
Being dissapointed with how small sata was and not understanding how a smaller connector could be faster when IDE had so many pins.
I remember the first 1.4ghz dual core and being confused about how they worked. Was it 2 1.4ghz cores, or 2 0.7ghz cores together for a 1.4ghz cpu.
I remember dance of the sugar plum fairies was the only song I'd listen to because it came included in windows 95.
I'm a lot more tech literature now, I was only a child back then. Currently 21.
But I still miss those times.
I want green PCBs again ;_;
>>51697473
no that old, i remember installing wotlk on 80gb hdd, 256 ram and 1.6 celeron, it was like 5 years ago
