newbie: RAID 5 or RAID 6?

[brannsiu]

I have getting more and more portable and desktop external hard drives and all the data has no backup now. I am worried my hard drives will fail sometimes later so I must get started to learn something.

I have never used anything like NAS or RAID, I just began to read some introduction articles on the web last night


Now the only thing I know is NAS is a mini system that mainly consists of hard drives and allows network access, which is something like a personal network, consuming less power...

RAID is the method of running a NAS.



In fact, I am now having a total of 8 HDDS already, most of them are 3.5 and some of them are 2.5 in size, and I will require more capacities as time passes by.

What should I do now to get started? What hardware should I buy as a minimal ? Anything I have to pay special attention to?

I think RAID 0 and RAID 1 are neither my ideas because RAID 0 even has higher risks of losing files while RAID 1 has a big waste of capacities, only 50% of total capacities can be used right?

How about RAID 5? Is it the best solution for home user like me? I need some strategies to implement to my files now to reduce the chance of losing files in case of HDD failure

 

[rhysiam]

If I understand you correctly, I think you've made the common mistake of equating RAID with backup. RAID is absolutely NOT a substitute for a good backup strategy.

There are all sorts of potential sources of data loss: theft, fire/flood/lightening strike, virus corruption, ransomware, user error (don't dismiss it, happens more than you might think), software or hardware error causing file corruption.... and HDD failure. From the list above RAID protects you from HDD failure only, and nothing else. The big advantage RAID 1/5/6/10 (the ones that actually have redundancy) give, is that they allow "high availability", that means that a drive can fail and be replaced without impacting on users (they can keep working on their files oblivious to the HDD failure). That's obviously really important in lots of corporate situations and is why RAID is so widely used. But for a home environment, do you really care? Unless you have hot-swap drives you'll have to reboot the computer and reinitialise the array anyway, so what advantage does RAID give you?

Add to that my first point above, if the data is important, it needs to be backup up, preferably offsite or at least in a different and secure location. So if you have a backup anyway, RAID offers very little to a home user.

A simple backup solution is to pick up a cheap external USB drive and make a regular copy of all your important data. If you can safely store it at work, or somewhere away from the home that's ideal. Bring it back home periodically to update the backup (the more often you do it, the less data you lose if something fails). Some people go with two drives, one onsite and one offsite, which get swapped weekly (or whatever strategy you want), so you have an up-to-date version available for smaller issues, but a relatively recent copy offsite in case of a major issue.

There are loads of other options too, but that's a common one.

You can add RAID to that strategy if you're really worried about a HDD failure and don't want to lose data at all. But make sure it's added to a good backup strategy, rather than being used in place of one... because RAID does NOT equal backup.

 

[USAFRet]

...to reduce the chance of losing files in case of HDD failure

A failed drive is probably the least likely way to lose data.
As above, RAID is not a backup.

Accidental deletion, corruption, virus...all far more likely.

My NAS box is running RAID 5. 4 x 3TB drives, leaving 8TB effective space.
But that is in dedicated hardware, with a dedicated RAID controller.
And it is fully backed up to another 8TB drive via USB.
And really important stuff also lives on a drive in the desk drawer at work.

 

[USAFRet]

As far as the NAS box...the newer ones are a lot more than just a little box of drives.
A full fledged PC (Linux based), that does a whole lot of stuff, like on the fly 4k transcoding video, music, virtual machines...along with traditional NAS functions.

 

[brannsiu]

If I understand you correctly, I think you've made the common mistake of equating RAID with backup. RAID is absolutely NOT a substitute for a good backup strategy.

There are all sorts of potential sources of data loss: theft, fire/flood/lightening strike, virus corruption, ransomware, user error (don't dismiss it, happens more than you might think), software or hardware error causing file corruption.... and HDD failure. From the list above RAID protects you from HDD failure only, and nothing else. The big advantage RAID 1/5/6/10 (the ones that actually have redundancy) give, is that they allow "high availability", that means that a drive can fail and be replaced without impacting on users (they can keep working on their files oblivious to the HDD failure). That's obviously really important in lots of corporate situations and is why RAID is so widely used. But for a home environment, do you really care? Unless you have hot-swap drives you'll have to reboot the computer and reinitialise the array anyway, so what advantage does RAID give you?

Add to that my first point above, if the data is important, it needs to be backup up, preferably offsite or at least in a different and secure location. So if you have a backup anyway, RAID offers very little to a home user.

A simple backup solution is to pick up a cheap external USB drive and make a regular copy of all your important data. If you can safely store it at work, or somewhere away from the home that's ideal. Bring it back home periodically to update the backup (the more often you do it, the less data you lose if something fails). Some people go with two drives, one onsite and one offsite, which get swapped weekly (or whatever strategy you want), so you have an up-to-date version available for smaller issues, but a relatively recent copy offsite in case of a major issue.

There are loads of other options too, but that's a common one.

You can add RAID to that strategy if you're really worried about a HDD failure and don't want to lose data at all. But make sure it's added to a good backup strategy, rather than being used in place of one... because RAID does NOT equal backup.

Hello

I'm quite confused. Why isn't NAS or RAID a backup?

For RAID 1, it's protected against hard drive failure. By common sense, it's far less likely to have two drives failed at the same time without any time for you to purchase a new drive and replace it. Being less likely to fail a drive should mean being less likely to lose data.

Especially for RAID 5 or even RAID 6, where only one or two drive is used as parity and the rest of drives could serve as
storage totally, failing two or three drives AT THE SAME TIME without rescue time to purchase a new drive is very unlikely.

Isn't it?

OK, if I can assume that NO lighting, NO electric failure, NO theft, NO mistake, NO virus, is RAID 5 the best solution for me?


In fact, I don't need to have speed increased with RAID, most of my files are static and will be only read but not processed. Is a traditional backup of important files with external portable USB drives the most economic solution for me to keep the files for my lifetime ?

However, what is the best way or if there is any freeware which would help me synchronize two drives (original drive and backup drive) , because for the original drive, new files will be added every day and some files may be deleted over time,
also filename and folder structure will be changed too. I don't want to do it every day or every week which requires a copy/paste and replace the 4TB or 8TB sizes of files which will forever

What is the cleverest way to synchronize ? (i.e. comparing the file structure or folder structure, copying only new files, deleting old files ,without copying and replacing the whole disk)

 

[rhysiam]

OK, if I can assume that NO lighting, NO electric failure, NO theft, NO mistake, NO virus, is RAID 5 the best solution for me?

Because all those things you "assume" are every bit as likely as a HDD failure. It's a bit like locking one door of your house, but leaving all the others unlocked, and then assuming your house is somehow secure from a break in. There's loads of posts on this from people who know far more about storage than I do. Here's one of the many examples: https://www.storagecraft.com/blog/5-reasons-raid-not-backup/
I'm not even suggested you might do something silly, it's just a fact that things happen. Even something as simple as a power outage when a key fine is in the middle of a save can be enough to cause corruption and issues which any RAID array will simple replicate (overwrite the good save with the corrupted copy)... data gone!

If you care about your data you need a backup. Raid is not backup. I'll make a few comments about NAS & storage below - but whatever you decide to go with, make sure you get a backup solution in place for any data you care about.

NAS:
A NAS is a good option if you have multiple devices and want to centralise all your storage, rather than having important data spread across multiple . Most (all - I think) multi-drive NAS units will support redundancy of some form or another. So something like a Synology or QNAP 2 or 4 bay unit might suit your needs. You may need to buy new disks however, as not all drives are suitable for use in a 24/7 device like that. Check the manufacturer's website for the supported drives.

If you only ever work from one computer, then there's really no point getting a NAS. Just access the drives locally.

In terms of backups - if you have a decent internet connection there are a number of cloud backup options available. If you do go with a NAS, some brands (particularly the more featureful (and expensive!) brands like Synology and QNAP) will automatically integrate with cloud backup solutions and can be automated, and even setup to send email notifications of success and/or failure.

Alternatively, if you want to go low-tech for backup, just get a large, cheap external USB drive and copy data to it from Windows. Copy and Paste works fine.
If you're prepared to have a go with command line tools you can use a tool called robocopy which can be used to mirror two directories. You can also easily make that into what's called a batch file which can sit on your desktop, so all you have to do is double click and it will run your backup for you. I can point you in the right direction for that if you're interested.

There's lot of ways of doing it. But first, can you be a bit clearer about what you want?
Do you want to centralise storage from lots of different devices and HDDs (then NAS & backup)?
Do you just want to make sure your data is safe is something goes awry (then just a simple backup)?