JonathanM

Format doesn't clear the drive, it just writes a new table of contents with no entries. All the old ones and zeroes from the deleted data are still there. To remove a drive without effecting parity, you must write all zeroes to the drive, which removes any existing format as well as any traces of previous data. Writing all zeroes takes a rather long time, typically many hours. It's normally much quicker to redo parity.

Typically you would unplug and switch the wires to the headers on the motherboard, so the reset button is wired to the power header, and leave the power button wires disconnected.

When you no longer trust it. All remaining disks must be read flawlessly to reconstruct a failed disk, so if another disk you don't suspect of failure fails, then you are relying on a disk you don't trust to rebuild it. As far as how to tell? That's part intuition and part analysis. All disks will fail eventually given time, the gamble is waiting until the last moment. Increased re-allocated sectors that happen recently and the count continues to increase, that disk is very likely to die soon. Nobody can predict the future perfectly, so you just have to use your best judgement, analyze the SMART numbers for that specific manufacturer. Some people have a very low tolerance for risk, and replace drives as soon as they show any sign of trouble. Some people like to live dangerously, and wait for a drive to actually get dropped from the array to replace it. In any case, drive redundancy and the ability to replace a failed disk does not mean you don't need backups of anything you don't want to lose. There are MANY ways to lose data that don't involve hard drive failure.

That's arguably the safest way to do it. It eliminates a bunch of shared variables that can kill a drive prematurely, like shipping damage. The last thing you want is to have a bunch of drives that were shipped with inadequate packing that FedUPS drop kicked across their warehouse. Or a whole box of drives that got dropped at the distributor, so they don't have any external signs of damage, just high g loads that probable won't matter, but could. If you really want to get a bunch of the same drives, try to stagger the purchases ideally both in time and location. Never buy 2 that will ship in the same box.

Unrealistic to expect more than 2 parity for any group of drives. However, having multiple groups is definitely being worked on, so your overall goal of increasing parity drives on a single Unraid install is happening sometime soon.

On what disk?

ASI

My distributor in the USA says they will have stock on April 30th.

Use the Unassigned Devices plugin to map the external share to a path in /mnt/remotes, then use that path in the container host side, probably need to use r/w slave.

That file only exists in RAM while the server is running, and is extracted from the archives on the USB every reboot. Any changes you make need to be redone after each boot. Best way is "CA User Scripts" plugin, write a short script to accomplish the edit, and set it to run "At startup of array"

That implies an issue with the VPN connection, credentials or endpoint issues are most common, the supervisord.log will have more information about what is happening.

Keep in mind the protocol you choose must be supported by whatever switch you are connected to. In general however, LAG doesn't provide a significant performance improvement for most use cases.

Unraid doesn't support hot-swap. The Unraid parity array does indeed give you fault tolerance for either a single or double drive failure depending on whether you assign 1 or 2 parity disks. It is NOT RAID5 or RAID6, the data is NOT striped across devices, each drive has its own valid filesystem. The parity drives are independent from the data drives and hold no sensible data, only the parity bits required to rebuild a failed drive. The advantages of the Unraid parity array is greater resilience and possible power saving, as unused drives can be spun down, also if there are drive failures beyond the tolerance level each remaining data drive remains readable. The disadvantages compared to RAID is speed, as reads are limited to a single device, and writes must update 2 or 3 devices. Also, since each drive is a separate filesystem, any single file can only be as large as the free space on any individual drive. The filesystems from each drive are usable as a group via user shares, which can span multiple drives, each unique root folder on the data drives is a user share, and the file tree view of all those folders is merged when looking at the user share. I suggest looking at some of spaceinvader one's videos on youtube, he has some good basics of Unraid as well as more advanced use cases.

No, that's perfectly fine. Your plan looks good to me, hopefully you were able to get it done.

See if this helps.