[Discuss] Debian 11 -> 12

[markw at mohawksoft.com]

> On 5/30/24 09:47, markw at mohawksoft.com wrote:
>> All that said, OMG ZFS is absolutely the way to go for any new
>> deployment
>> unless a bare bones hardware performance is required.
>
> I would amend that: Any new deployment…that is conventional (from ZFS's
> perspective) and can afford the necessary expertise.

I don't understand why you think ZFS has any more base complexity than
something like LVM.

create -f snoopyz raidz /dev/disk/by-id/wwn-0x50014ee20911cd02
/dev/disk/by-id/wwn-0x50014ee003e1e0da
/dev/disk/by-id/wwn-0x50014ee20be68e9f
/dev/disk/by-id/wwn-0x50014ee20c8617e0

(I use disk/by-id because it doesn't break when drives are reordered, but
you could easily use /dev/sdb /dev/sdc etc.)

There done. You have a pool. What's hard about that?

zfs create -V 200G snoopyz/qemu_vm_image

Is that harder than LVM's lvcreate?

or
zfs create -V 200G -s snoopyz/qemu_vm_image



The "-s" will give you a 200G /dev/zd[n] device that is "sparse" or "thin
provisioned" which means it won't use space until it is written. You could
allocate a block device that is bigger than the amount of disk you have.
Back-fill it as it grows.


zfs set compression=lz4 snoopyz
That will enable compression on the pool.

zfs set compression=lz4 snoopyz/qemu_vm_image

>
> I have played with a lot of software over the years, and when I tried
> ZFS, I got it to work on my Intel laptop. Though personally, as a matter
> of taste, I found it ornery. And it flat out *crashed* when I tried to
> do the same stuff on a Raspberry PI 4. I was certainly doing unusual
> things, if nothing else running ZFS on a Raspberry PI 4 is apparently
> weird. But I still don't expect mainstream software to crash in my face,
> and certainly not software that I am supposed to trust my data to.

Dude, I had ZFS running on a RPI4 and just upgraded it to an RPI5. Zero
issues.

markw at raspberrypi:~ $ zpool status
  pool: backupz
 state: ONLINE
  scan: scrub repaired 0B in 04:25:16 with 0 errors on Tue May 28 12:57:24
2024
config:

	NAME                        STATE     READ WRITE CKSUM
	backupz                     ONLINE       0     0     0
	  raidz1-0                  ONLINE       0     0     0
	    wwn-0x50014ee215801a06  ONLINE       0     0     0
	    wwn-0x50014ee215e7129a  ONLINE       0     0     0
	    wwn-0x50014ee215e7155f  ONLINE       0     0     0
	    wwn-0x50014ee26ad538b2  ONLINE       0     0     0
	cache
	  /zcache                   ONLINE       0     0     0

errors: No known data errors
markw at raspberrypi:~ $ uname -a
Linux raspberrypi 6.6.20+rpt-rpi-2712 #1 SMP PREEMPT Debian
1:6.6.20-1+rpt1 (2024-03-07) aarch64 GNU/Linux


>
> As far as I can tell ZFS is a specialized tool, with impressive
> features, but rough edges. It is not a smoothly crafted, general purpose
> package suited to a general audience.

Not at all. I don't understand what issues you've had because I have not
seen them, but ZFS is very stable. The only time I have ever had a
stability issue was when the underlying storage or cabling was so bad it
was virtually unusable and I don't think linux would do well with that on
LVM either.

>
> -kb, the Kent whose Raspberry PI 4 is, at this moment, running a custom
> built kernel so it can happily boot and run from a pair of spinning
> drives, using Linux SW raid 1, which though limited and doesn't scale to
> gigantic disks very well, otherwise works great, across architectures,
> even when used in weird ways.

Why did you make a custom kernel? Keep the SD card as a boot loader, and
use an SSD for your root partition. Everything stays stock.

markw at raspberrypi:~ $ df
Filesystem      1K-blocks       Used  Available Use% Mounted on
udev              3946080          0    3946080   0% /dev
tmpfs              824176       6432     817744   1% /run
/dev/sda1       460367736  264830908  172077920  61% /
tmpfs             4120800       1312    4119488   1% /dev/shm
tmpfs                5120         48       5072   1% /run/lock
/dev/mmcblk0p1     522232      75368     446864  15% /boot/firmware
backupz        2912676224  709389568 2203286656  25% /backupz
tmpfs              824160        144     824016   1% /run/user/1001
tmpfs              824160        160     824000   1% /run/user/1000
backupz/media  4132240512 1928953856 2203286656  47% /backupz/media


My root is a 460G SSD

markw at raspberrypi:~ $ cat /boot/firmware/cmdline.txt
console=serial0,115200 console=tty1
root=UUID=e6ec0371-200b-439b-a259-c60f391a56ed rootfstype=ext4
fsck.repair=yes rootwait quiet splash plymouth.ignore-serial-consoles
cfg80211.ieee80211_regdom=US

markw at raspberrypi:~ $ blkid /dev/sda1
/dev/sda1: UUID="e6ec0371-200b-439b-a259-c60f391a56ed" BLOCK_SIZE="4096"
TYPE="ext4" PARTUUID="2bf37e9b-01"


I use the UUID of the /dev/sda1 file system in the cmdline.txt file, and
also put that in /etc/fstab.

No mods to the software, hardware, or the need for a custom kernel.


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