[CONFIGURATION] Raid after the fact

[rdonnelly]

Hi, I was wondering if I cloned my hard drive to another would it be possible to use them in a raid array?
Could I just leave all of my data partitions, and reinstall Linux again on / to set up the drivers?

TIA

[oshunluvr]

Probably not. I assume you're using a file system other than BTRFS. If you were, then definitely yes.

Google is your friend, because this says you can I guess: guyrutenberg.com/201definately3/12/01/setting-up-raid-using-mdadm-on-existing-drive/

I'd make a backup if I were you.

[rdonnelly]

Wow that seems like a lot to do, for me it would be easier to do a backup and restore my data to the raid array.

Thanks for the tips.

[jglen490]

There's a difference between recovery and restore. A Raid array provides redundancy which helpful with recovery and reliability, but RAID can fail and cause loss of data in which case you still need a backup/restore solution. There are lots of RAID configurations, read up on that first. Then backup your data. Then choose and configure a RAID setup. I don't know of any enterprise solution or provider that does not use backup and recovery with RAID. At least none that are still in existence.

[rdonnelly]

There's a difference between recovery and restore. A Raid array provides redundancy which helpful with recovery and reliability, but RAID can fail and cause loss of data in which case you still need a backup/restore solution. There are lots of RAID configurations, read up on that first. Then backup your data. Then choose and configure a RAID setup. I don't know of any enterprise solution or provider that does not use backup and recovery with RAID. At least none that are still in existence.

I understand the risks, believe me. But I have heard that raid makes for a faster file system as well. I was just going to enable it within my bios, and then run an install of Kubuntu.

I back up my data daily at 5 PM with LuckyBackup and Crontab, to an extra internal hard drive, and monthly between 2- 1 TB USB3 HDs, one stays in the office, and another in a building totally separate for redundancy. About a month ago, I dual booted into Win 10, after that my hard drive was trashed, and was not recognized in Bios any more, when I use Linux, my HD light hardly ever comes on, but in windoze that HD is rattling away the entire time. I did not even put windoze in my HD this time. I have Win 7 32 Bit in a Vbox, and that is all I need.

Another question about raid, when I use Clonezilla to clone partitions, would the raid array show as 2 HDs, or one?

[jglen490]

It's your choice, of course, but RAID is used for complex and very active systems that track a lot of data and changes to that data. If you have that situation, then RAID is probably for you. If you are looking for data reliability, then a RAID is probably for you. And while RAID is not intended as a data backup target, it quite often is used that way, but generally with highly volatile, usually major enterprise type system. Do not expect that a properly configured RAID will have a "faster" filesystem than a comparable non-RAID configured system. Whether a mirroring configuration, or striping, or some other RAID process is involved, the write process is more complex. I don't have facts or statistics, so you will want to verify that.

What you would do is, figure out what RAID configuration you want to use, get and install what additional hardware you need, then backup your data. Backup any data that has importance to you, and make sure you have your OS installer nearby. Once you build your RAID, those disks are formatted and the data is gone. Of course you don't need to RAID your OS. Then when the dust settles, restore your data onto the RAID array. Then ... happy computing. But that's the short version.

Make sure you set up a proper backup procedure and backup your RAID data periodically.

[oshunluvr]

I understand the risks, believe me. But I have heard that raid makes for a faster file system as well.

Are you sure you understand RAID and it's implications well enough? Your first post you talked about "cloning" your drive, which would indicate an interest in RAID1 a.k.a. "mirroring." There is absolutely no performance gain in using RAID1. What you get from RAID1 is redundancy and the least likely situation where you would use all your data. If you're looking to increase performance, you would want to use RAID0. With RAID0 your data is all at risk. 100% loss if one drive fails. There's other commonly discussed RAID configurations - 10,5,6 - but they all require more than 2 drives so become costly rather quickly and at a questionable benefit.

Then there's how you implement RAID. If you use BIOS or motherboard based RAID, you introduce an additional level of possible data loss - the motherboard dying. If you were going to use RAID, I would recommend using Linux "soft" RAID via tool called mdadm. Finally, there's "file system RAID" introduces by BTRFS and ZFS file systems. There are dozens if not hundreds of posts on this very forum about those file systems and their benefits/pitfalls. I have used RAID of most types, mostly as an intellectual exercise. I never stayed with it for long as it always ended up more trouble than it was worth.

IMO as a PC user since before you could buy a home computer - that would be 44 years - and a Linux user since 1997 or so, there are better ways to both prevent data loss AND to improve file system performance. RAID in the home environment just isn't a big enough benefit to be worth the effort or risks. RAID was never intended for the "casual" or home user. It's for mission-critical environments with immense amounts of data where data loss or restoring a backing that takes hours or days is either extremely costly or dangerous.

If you really want to improve FS performance and increase data safety, buy an SSD and get a good backup device. You can get a decent name brand 128GB drive for as little as $20 or a top-o-the-line 1TB Samsung for just over a hundred and either will be 10 times faster than the best hard drive. Make regular backups (automate it if you can, like I do). Now you've achieved or exceeded all the benefits of RAID without the dangers or complications. Of course, if you're just interested in learning about RAID and playing around with it, by all means have a go at it.

It's also worth noting that very few people actually take the time to learn about and tune their file systems. Assuming you're using EXT4, you might want to start by researching how to tune and mount the file system before making things difficult for yourself with RAID. Also, there are many other file systems that offer improved performance in certain use-cases and/or additional file system features and it's worth researching them also.

[rdonnelly]

It's your choice, of course, but RAID is used for complex and very active systems that track a lot of data and changes to that data. If you have that situation, then RAID is probably for you. If you are looking for data reliability, then a RAID is probably for you. And while RAID is not intended as a data backup target, it quite often is used that way, but generally with highly volatile, usually major enterprise type system. Do not expect that a properly configured RAID will have a "faster" filesystem than a comparable non-RAID configured system. Whether a mirroring configuration, or striping, or some other RAID process is involved, the write process is more complex. I don't have facts or statistics, so you will want to verify that.

What you would do is, figure out what RAID configuration you want to use, get and install what additional hardware you need, then backup your data. Backup any data that has importance to you, and make sure you have your OS installer nearby. Once you build your RAID, those disks are formatted and the data is gone. Of course you don't need to RAID your OS. Then when the dust settles, restore your data onto the RAID array. Then ... happy computing. But that's the short version.

Make sure you set up a proper backup procedure and backup your RAID data periodically.

Thank you jglen490 and osh. You have convinced me that its not really worth the effort at this point. I am still backed up daily, and monthly anyways.