Re: raid10 redundancy

[Reindl Harald <h.reindl@thelounge.net>]

Am 07.05.21 um 03:47 schrieb d tbsky:
> Phillip Susi <phill@thesusis.net>
>> No, it only depends on the number of copies.  They layout just effects
>> the performance.
> 
> I thought someone test the performance of two ssd, raid-1 outperforms
> all the layout. so maybe under ssd it's not important?
> 
>> No; 2 copies means you can lose one disk and still have the other copy.
>> Where those copies are stored doesn't matter for redundancy, only performance.
> 
>   I am trying to figure out how to lose two disks without losing two
> copies. in history there are time bombs in ssd (like hp ssd made by
> samsung) caused by buggy firmware.
> if I put the orders correct, it will be safe even the same twin ssd
> died together.

forget what you try to figure out, you can't control which two disks 
fail at the same time, period

you can minimize the risk by using different disk types and/or 
distribute their age (i am doing that currently by replacing all disks 
on a backup server with two weeks between)

in case of a frimware timebomb you have no chance in case of identical 
disks and when you seek a soluton whuch survives two failures then for 
the sake of god use one which is called RAID6 and not RAID10

that you can lose two disk in a RAID10 with luck is exactly that: LUCK - 
period