Author name: Dan Langille

I've been playing with computers since I read an Elementary Electronics magazine way back in the 1970s. I started contributing to open source projects in 1998. After that, I gradually moved from being a software developer to being a systems administrator.

Test run – moving to a SATADOM based zpool (zroot) using zfs snapshot and send | recv

Yesterday I managed to move a zroot zpool from larger drives to smaller drives using snapshot, send, recv. Today, I’m doing the same thing. Yet, what is different? using serial numbers in some partition labels moving to SATADOM This really is a dry-run for when I do this on my production host, r730-01 – apart from the whole moving-to-smaller-drives part. host ssh keys NOTE: not shown in this post are messages like this: […]

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Test run – moving to a smaller zpool (zroot) using zfs snapshot and send | recv

Today, I’m going to try a test run of moving a zroot into a smaller zpool. Over the past few posts, I’ve tested moving to smaller zpools using zfs remove. That’s not what I want to do with my zpool – mostly because it does not leave you with a functioning original zpool. I’m following https://www.hagen-bauer.de/2025/08/zfs-migration-to-smaller-disk.html and I particularly like their use of labels on each partition. In this post: FreeBSe 14.3 mfsbsd-14.2-RELEASE-amd64

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Doing stupid things with zpools

Over the past week or so I’ve done some “stupid” things with zpools. I wanted a place to document some of the things I’ve read along the way: renaming a zpool: https://forums.freebsd.org/threads/renaming-zfs-pool-via-zpool-import.65498/ getting the mrsas driver instead of the mfi driver – https://forum.netgate.com/topic/102137/dell-r330-perc-h330-sas (in short, at the loader prompt, issue `set hw.mfi.mrsas_enable=”1″` and then `boot`) I’ll add to this list as I find new stuff.

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Moving a zpool to smaller drives with UEFI #ZFS #FreeBSD

This is another in the series of shrinking zpools. In this test, I’m repeating the previous test, only with UEFI, not BIOS, boot partitions. Partitioning root@r730-04:/home/dvl # gpart create -s gpt mfisyspd0 mfisyspd0 created root@r730-04:/home/dvl # gpart create -s gpt mfisyspd1 mfisyspd1 created root@r730-04:/home/dvl # gpart create -s gpt mfisyspd2 mfisyspd2 created root@r730-04:/home/dvl # gpart create -s gpt mfisyspd3 mfisyspd3 created root@r730-04:/home/dvl # gpart add -t efi -s 260M -a 4k mfisyspd0 mfisyspd0p1

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Moving a zpool to smaller drives #ZFS #FreeBSD

After succeeding with whole drives and with partitioned drives, I’m ready to try with more complex partitions. This is a repeat of the failed attempt a few days ago. Parition creation The partitions are created Create the schema: root@r730-04:/home/dvl # gpart create -s gpt /dev/mfisyspd0 mfisyspd0 created root@r730-04:/home/dvl # gpart create -s gpt /dev/mfisyspd1 mfisyspd1 created root@r730-04:/home/dvl # gpart create -s gpt /dev/mfisyspd2 mfisyspd2 created root@r730-04:/home/dvl # gpart create -s gpt /dev/mfisyspd3 mfisyspd3

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Let’s try shrinking a whole-disk zpool

After yesterday’s failure to shrink a parition-based zpool. After reading this post, you want also want to read this other successful post. You will recall that expedition ended with: dvl@r730-04:~ $ zpool add zroot mirror /dev/da2p3 /dev/da3p3 cannot use ‘/dev/da2p3′: must be a block device or regular file Today, I’m going to try the same thing with whole disks, just to see if that works. You might also want to read Moving a

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Moving a zpool to smaller drives #ZFS #FreeBSD – fails

This post is part of a series of storage-related posts. The goal: move the zroot of r730-01 to smaller drives. NOTE: This approach failed. Investigations continue, however this post is not something you should try. This other successful post might be useful, although I still don’t know why the attempt in this post fails. Earlier today, as the first step in my proof-of-concept, I moved the zroot of r730-04 from 2x SATADOM device

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Creating a backup boot drive from a zroot mirror

Today, using FreeBSD 14.3, I’m going to test booting from a drive which is a mirror of the boot drives. This is what I’m booting from: root@r730-04:~ # zpool list NAME SIZE ALLOC FREE CKPOINT EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT zroot 923G 1.72G 921G – – 0% 0% 1.00x ONLINE – root@r730-04:~ # zpool status zroot pool: zroot state: ONLINE scan: resilvered 3.74M in 00:00:01 with 0 errors on Thu Nov 20

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gpart backup | gpart restore does not alway give you exact replication

Today I was setting up some drives for testing. I did this manually: root@r730-04:~ # gpart create -s gpt da2 da2 created root@r730-04:~ # gpart add -t efi -s 260M -a 4k da2 da2p1 added root@r730-04:~ # gpart add -t freebsd-swap -s 8G -a 4k da2 da2p2 added root@r730-04:~ # gpart add -t freebsd-zfs -a 4k da2 da2p3 added root@r730-04:~ # gpart show da2 => 40 62533216 da2 GPT (30G) 40 532480 1

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