Re: success with ZFS on armv7

[fgs%SDF.ORG@localhost]

hi list, hi alistair 
On Wed, Nov 10, 2021 at 10:51:56AM -0800, Alistair Crooks wrote:
> Thanks for the information, great that it's working on armv7.
My pleasure. 
 
> Do you have any idea how not-performant ZFS is, compared to FFS? (I suppose
> being on top of cgd won't help that)
 
# dd if=/dev/zero of=./test.file bs=4k count=10240
[...]
41943040 bytes transferred in 20.585 secs (2037553 bytes/sec)
 
and a bigger one
# dd if=/dev/zero of=./test.file bs=1m count=1024
[...]
1073741824 bytes transferred in 539.371 secs (1990729 bytes/sec)
 
that was a quick write test i've just done, on top of the CGDs. 
i'll do another write test without CGDs in the middle and report back,
need to find more HW to do it on. expect tomorrow-ish.
 
for comparison, here's the same tests on the FFSv1 / partition
(sadly, resize_ffs doesn't work for v2 on armv7, or i could've tried that
too)
 
# dd if=/dev/zero of=./test.file bs=4k count=1024
[...]
4194304 bytes transferred in 1.028 secs (4080062 bytes/sec)
 
# dd if=/dev/zero of=./test.file bs=1m count=1024 
[...]
1073741824 bytes transferred in 89.142 secs (12045296 bytes/sec)
 
> Any issues with memory and ARC when using it?
dont ask, lol. the rpi i'm doing this on just has 1GB of main 
memory. 
 
you really do not want to copy larger files (that wont fit into RAM)
onto the ZFS, it behaves all sorts of ways when it hits the memory cap.
 
and adding swap to it - which with 4 attached USB sticks will have to go 
onto the SD-card - just makes it sluggishly slow, down to a few kb/s.
to add to it, afaik the rpi shares one USB bus between the 4 USB2
ports and ethernet...
 
will report back with numbers for write speed without the CGDs in the
way. sorry alistair, i replied to you directly before. here's a copy
of the mail, going to the list.
 
thanks & stay safe