When you are running a server just to store files (a NAS) you generally set it up so multiple physical hard disks are joined together into an array so if one fails, none of the data is lost. You can replace a failed drive by taking it out and putting in a new working drive and then the system has to copy all of the data over from the other drives. This process can take many hours to run even with the 10-20 TB drive you get today, so doing the same thing with 140 TB drive would take days.
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It will take a long time and while it runs it will use a lot of resources so the server can be bogged down. It is also a dangerous time for a NAS, because if you have a drive down, and another drive dies, the whole pool can collapse. The process involves reading every bit on every drive, so it does put strain on everything.
Some people will go out of their way to buy drives from different manufacturing batches so if one batch has a problem, not all of their drives will fail.
The way striping works (at an eli5 level) is you have a bunch of drives and one is a check for everything else. So let’s say you have four 10tb drives. Three would be data and one would be the check, so you get 30tb of usable space.
In reality you don’t have a single drive working as a check, instead you spread the checks across all of the drives, if you map it out with “d” being data and “c” being check it looks like this: dddc ddcd dcdd cddd
This way each drive has the same number of checks on it, and also why we call it striping.