Dark Owl wrote: ⤴Sun Sep 19, 2021 5:21 am
Petermint wrote: ⤴Sun Sep 19, 2021 4:13 am
Is your data of a nature where you can divide it up over separate disks without RAID? Music directory on one disk, Videos on the second disk, C code on the third disk, and Recipes on the forth disk. No RAID problems. They can run at any speed...
...One good 7200 rpm 3.5" disk could give you all that without hassle...
...Experiment with the 3 * 2 TB disks in software RAID 5. If they fail, get the one big drive.
You misunderstand. I'm not overly bothered about raw I/O performance, the mirrors are purely for disaster recovery. RAID1 loses nothing at all if a disk fails, but backups are always a session behind. Also, RAID5 (etc) cannot be read in the absence of a RAID controller (or software) whereas individual drives from a RAID1 are not dependent on the controller and can be read normally by direct access should it prove necessary (as I have demonstrated).
Petermint wrote: ⤴Sun Sep 19, 2021 4:13 amOne good 7200 rpm 3.5" disk could give you all that without hassle
Oh yes, the "all my eggs in one basket" approach. I don't think so! Backing up multi-terabyte drives is a pain in the arse too.
Petermint wrote: ⤴Sun Sep 19, 2021 4:13 am
Is your computer restricted to 2.5" disks?
Not in the least. The RAID drives are 3½", I have 5¼" optical drives, the system boots from a 2½" SDD, and there is another 3½" HDD for temp, RAM paging, etc. This is a full-size tower case with 7 external bays and multiple internal ones (even more with my DIY drive cage)!
Petermint wrote: ⤴Sun Sep 19, 2021 4:13 am
I would toss the 1.5 inch disk.
Presuming you're talking about the 1.5TB (not 1.5") odd-one-out, I assume you have plenty of cash to spend. I don't.
I'm getting the impression you believe that RAID is a backup, especially after these comments that say "...the mirrors are purely for disaster recovery..." and "...Backing up multi-terabyte drives is a pain in the arse too..." Backing up multi-terabyte drives is not a "pain in the arse" (or anywhere else) if you use the correct software and have your system setup correctly. I have two 4TB and one 8TB (divided into two 4TB partitions) SSDs in my laptop and it takes only minutes to back up all of them daily (often in less than a minute, depending on how much data has been added, changed, or removed).
No matter what Operating System (OS) is being used, there is a huge misunderstanding among computer users of the the difference between backups and redundancy. Redundancy is the concept of having more than one component in a system of any kind to ensure continuous operation should one component fail. A naval example (called planned redundancy) would be having two engines and props on a ship when one of each would be adequate, less expensive, and require less maintenance. With only one engine and one propeller, if either fails, then the ship would be dead in the water. With two engines and props, if any one failed, the remaining engine/prop pair would still be able to keep the ship moving, something very desirable since getting out and walking when dead in the middle of an ocean is a wee bit difficult.
The same is true of RAID. Just to get it out of the way, RAID 0 is a throwback to the days when HDDs were small and slow. RAID 0 was used to create a larger volume and increase speed. Today, larger drives eliminate the need of RAID O to create a larger volume and SSDs provide more speed by their little 'ol lonesomes than several HDDs in RAID 0. Also, more drive speed will not increase computer performance other than when booting, transferring files, etc. OS and program performance are not affected unless frequent drive access is needed. RAID 0 had the added disadvantage of having no failure tolerance; if any one drive in a RAID 0 fails, all data in the array is toast with little to no chance of recovery. Even expensive, professional data recovery is iffy at best. In my not so humble opinion, RAID 0 needs to go the way of the dinosaurs.
Other kinds of RAID are forms of redundancy. Their main purposes are to create larger volumes (RAID 1 being the exception) and to allow a computer or NAS to keep chugging along without data loss if one or more drives should fail (the number of failed drives allowed being dependent on the kind of RAID being used). There are redundancy schemes other than RAID that are often superior to RAID but I'll keep this discussion limited to RAID since it's the predominant topic in this thread; I also don't know all that much about them).
Continuous operation despite drive failure often a necessity in certain applications, most noticeably business applications or scientific applications (such as mission control for space flight). Other times, such as with personal home computers, it is just highly desirable. However, recovering from a drive failure doesn't have to be a major, time consuming operation (more on that shortly).
All redundancy will do is protect against drive failure (up to a point). There are two rules to keep in mind about RAID:
1. RAID is NOT a backup!
2. If you still think RAID is a backup, go back to rule #1.
Before you all break out the flame throwers to toast my buns (especially since my flame proof undies are at the cleaners), let me explain further. Not all data loss is from drive failures. User error (such as accidental deletions, accidentally formatting a drive, etc.; face it, we all have done at least one of these), theft, natural (and unnatural) disasters, ransomware, etc. can all cause data to be lost. Redundancy cannot protect data loss from those. If you have a RAID 1, for example, and you accidentally delete a file, that file will disappear from both the drives in the RAID--permanently (again, professional data recovery is expensive with no guarantees of success).
A NAS that is kept powered up and connected to computers, either directly (technically, a DAS) or over a network is also just redundancy and is not a backup.
The ONLY way to ensure the safety of data is for it to exist in more than one place. RAID is only one place. Lose the RAID (and RAIDs do break) and your data is lost for evermore. Any data storage kept connected to the computer, such as external drives or a NAS, can lose data to accidental deletion or ransomware. The same is true of separate, backup drives installed inside a computer. Someone steals the computer or it goes up in smoke due to a house fire, your data is toast (pardon the pun). Any data storage connected to a power source can be fried by a power surge.
Most data security experts recommend that data should exist in three, separate places (I'm a paranoid old coward so I have more than three). For most people, this is on a drive in the computer, on an onsite external backup drive that is kept disconnected from the computer and power (except while updating the backup) and stored away from the computer, and on an offsite backup drive. Onsite and offsite backup drives should be swapped out as often as possible to keep the offsite backup drive as up o date as possible.
How one sets up their computers will determine how easy or difficult making and updating backups will be. Default installations of Mint and its frequently used backup programs are not conducive to fast and easy backup procedures. The OS and programs should be kept separate from each other to allow the use of separate backup programs that are more ideally suited for each kind of backup. On my one drive wonder notebook, I partitioned the drive into two partitions, one for the OS, programs, and /home. The other partition is for data only. Other than two programs--Evolution Calendar and Sticky Notes--that insist on storing their day on hidden files in /home (which, fortunately, can be backed up to the other partition), I do not keep any data on the OS partition. This computer, due to age and limited capacity, now serves only as a backup computer.
My laptop has a single boot drive (grossly oversized for its use but it was the smallest one of the brand and type I wanted). Other than the two aforementioned programs, no data is kept on that drive. My data is stored on two 4TB SATA SSDs and one 8TB NVME SSD (divided into two 4TB partitions to allow the use of already on-hand 4TB SATA SSDs for backups; NOTE - I normally do not recommend organizing data with partitions; folders are far more efficient).
I use Timeshift to backup my OS and programs. Unlike most people and contrary to what is recommended, I also backup all data on that drive so I can restore any settings I may have changed (the only data, other than hidden files, being desktop shortcuts to my data drives and some files on the data drives, my calendar entries, and my sticky notes; the latter two are also backed up to a data drive). I also manually make all my snapshots. I make a weekly snapshot first thing on Monday morning (I let it run while taking care of business in the bathroom). I also make another one on an external backup drive. Before installing or deleting programs, installing potentially dodgy updates, and making an major settings changes, I make another snapshot. I only keep as many snapshots as what will fit in the Timeshift default window to save space.
Many people recommend keeping Timeshift snapshots in a separate partition to limit the amount of drive space they take up but if one sets Timeshift to keep only so many snapshots (or manually clean them out like I do), then running out of room will not be a problem and a separate partition is both not needed and will just waste space.
Timeshift is great for quickly restoring the OS, etc. to a previous point in time but is a rather dodgy and time consuming for restoring after a complete drive failure. Imaging is better for that.
On Saturday mornings, I image the boot drive using Rescuezilla. Foxclone is more popular and is probably better than Rescuezilla but I can't use it on my laptop due to its POS NVIDIA card. Clonezilla also works well but is a PITA to use. I test the first image of each month by restoring it to a spare drive in an external enclosure, then swapping that drive out with the boot drive in the computer (I've done it often enough, I can do the swap in just under a minute). Imaging and restoring images takes longer than making and restoring snapshots but it's less than five minutes for each operation which I kill doing something else, such as the aforementioned business trip. I keep my most recent images on my computer for convenience but I also copy them to an external drive just in case the internal drive the images are on go south (file permission issues prevented easily copying Clonezilla images to another drive).
I use a free folder/file syncing program called FreeFileSync (FFS) to make and update my data drives and partitions. It works by comparing the data drive or partition with the backup drive, then copies or deletes folders and files to make the backup drive essentially a clone of the data drive. Making the initial backup will take quite a while since all the data has to be copied from the data drive to the backup drive but updating the backup drive after that takes much less time since only new, changed, and deleted files are involved in the update. I typically spend only a minute or two (often less) updating my onsite laptop onsite external backup drives at the end of the day before sacking out.
There are other folder/file syncing programs but I like FFS because it has an easy to use GUI. It can be "hacked" to verify each file transfer went through correctly. It also has a feature called Versioning (which I strongly recommend) that will send any deleted files to a user designated Versioning folder. This protects me from losing any files deleted due to the originals becoming corrupted or accidentally deleted on the data drive.
I also use FFS to restore data to a drive (or its replacement) that has failed. I also use it to sync data between my laptop data drives and my desktop data drives and their backups (I'm currently between desktops but I'm still externally maintaining the desktop data drives and their backups). It's a very versatile program once you get familiar with it. It's also free!
This all sounds complicated but, once set up, updating backups and restoring from them is fast and easy. In your case, I strongly suggest just forgetting about using RAID and using your mirror drives in external enclosures as onsite backup drives, then, as you can afford it, get addition external drives for use as offsite backup drives. Drives cost money but they are far, far more reliable and far, far less expensive than professional data recovery that has no guarantee of success.
