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Advanced users • Re: RAID 1 (mirror) with two NVMe

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1) the bootfs has to be RAID 1 with 0.90 metadata. This way, the firmware "sees" no difference compared with a non-RAID rootfs. Other partitions can use 1.2 metadata and RAID1 or RAID 10 (also possible with 2 disks, increasing read performance on USB disks).
I think a typo: rootfs should be bootfs ?

Is this Pi5 only or also Pi4 when EEPROM is build from common source-code (after "Mon Apr 15 01:12:14 PM UTC 2024 (1713186734)" ) ?

Would this be be the same if you 'post-mount' (not from fstab) using dmsetup to create a mirror? see viewtopic.php?p=2146890&hilit=dmsetup#p2146890
>typo yes, of course, I corrected it in my post.

>pi4 this also works on pi4 w/USB or SD card. As long as the firmware does not write to the boot partition (AFAIK this does not happen anymore).

BTW, I always start using the RPI imager and then construct the RAID system in separate partitions, adding a tiny AUTOBOOT partition in front of all other partitions and keeping the start sector of the pre-existing partitions. The AUTOBOOT partition just stores the autoboot.txt file for switching between the two systems using the TRYBOOT feature and points to partitions 2 or 3 depending on the TRYBOOT flag. The first partitions on a 128GB SD card are, then:

Code:

/dev/sda1 : start=        7680, size=         512, type=c     #new tiny partition containing the autoboot.txt file/dev/sda2 : start=        8192, size=      524288, type=c     #original boot partition (non-RAID), shrunk to about 50%/dev/sda3 : start=      532480, size=      524256, type=c     #RAID member for RAID boot partition (with type=c to make the loader happy)/dev/sda4 : start=     1056767, size=   244396033, type=f     #extended partition/dev/sda5 : start=     1056768, size=    11730944, type=83    #original ROOT partition from the RPI imager shrunk to 5.5G/dev/sda6 : start=    12787713, size=    16777216, type=fd    #RAID member for RAID root partition
The boot partition is cut in half to make room for a second one. Some utilities warn about the reduced size, but it's still only 25% full.
The extended partition is a few percent less than the entire SD card to allow for the same partitioning on cards with slightly different size.

The only thing I can't perform while running on this system is shrinking the original root partition. The easiest way to prevent a newly created system to enlarge the root partition to the whole disk is to create a dummy partition, starting from location 10000000 to the device end, before the first boot, and then delete this dummy partition later in the process.

Statistics: Posted by abuelomg — Sun Nov 24, 2024 3:32 pm



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