Re: Linux ZFS Grub compatibility

[Xen]

On Sat, 9 Jun 2018, John Lane wrote:

> I have created a filesystem volume but I cannot read it. I've tried
> various features enabled and disabled without success. When I do  "ls
> (hd1,1)/ROOT/archlinux@/boot' I get errors for each file about the
> compression algorithm not being supported. Enabling or disabling
> lz4_compress does not help.

I went and rebooted to check out grub, after insmod zfs I was presently 
surprised that I could do:

  ls (hd2,msdos4)/msata/@/root/   (I believe) and see the file there

  root=ZFS=(hd2,msdos4)/msata/... did not work, I had to use
  root=(hd2,msdos4)

  and then could do ls ($root)/msata/@/root/

  (msata is the zpool name, root a dataset)

I am not a great fan of stackexchange which is why I didn't check your 
link out yet, but I'll have a look.

My zpool was created on Ubuntu without any special parameters, although it 
included an l2arc and slog that are both absent.

My system mixes both zvols and datasets and I am going to be lazy and just 
list the entire list output for the 2 datasets:

NAME            TYPE        CREATION               USED  AVAIL
msata/boot      filesystem  ma feb 19 19:17 2018    96K   300M
msata/root      filesystem  ma feb 19 19:18 2018    96K  20,0G

REFER  RATIO  MOUNTED  ORIGIN  QUOTA  RESERV  VOLSIZE
  96K  1.00x       no  -        300M    300M        -
  96K  1.00x       no  -         20G     20G        -

VOLBLOCK  RECSIZE  MOUNTPOINT  SHARENFS   CHECKSUM  COMPRESS
       -     128K  none        off              on        on
       -     128K  legacy      off              on        on

ATIME  DEVICES  EXEC  SETUID  RDONLY  ZONED  SNAPDIR     ACLINHERIT
   on       on    on      on     off    off   hidden     restricted
   on       on    on      on     off    off   hidden     restricted

CANMOUNT  XATTR  COPIES  VERSION  UTF8ONLY  NORMALIZATION         CASE
      on     on       1        5       off           none    sensitive
      on     on       1        5       off           none    sensitive

VSCAN  NBMAND  SHARESMB  REFQUOTA  REFRESERV  PRIMARYCACHE  SECONDARYCACHE
  off     off  off           none       none           all             all
  off     off  off           none       none           all             all

USEDSNAP  USEDDS  USEDCHILD  USEDREFRESERV  DEFER_DESTROY  USERREFS
       0     96K          0              0              -         -
       0     96K          0              0              -         -

LOGBIAS          DEDUP  MLSLABEL      SYNC  REFRATIO  WRITTEN
latency            off  none      standard     1.00x      96K
latency            off  none      standard     1.00x      96K

CLONES  LUSED  LREFER  FSLIMIT  SSLIMIT  FSCOUNT  SSCOUNT  SNAPDEV
-         11K     11K     none     none     none     none   hidden
-         35K     35K     none     none     none     none   hidden

ACLTYPE  CONTEXT  FSCONTEXT  DEFCONTEXT  ROOTCONTEXT  RELATIME  REDUND_MD
    off  none     none       none        none              off        all
    off  none     none       none        none              off        all

OVERLAY
    off
    off

That was not extremely lazy.

In general I believe I have lz4 compression.

So I wouldn't know currently what goes wrong with you.

Since your problem is with compression, I really have no clue.

This is currently an Ubuntu 16.10 system, but in all extents and purposes 
it is just 16.04.

I now see I am using an older version of zfs:

zfsutils-linux      0.6.5.8-0

The initramfs package is not even installed.

Grub on this system is Ubuntu default currently, so that means

2.02~beta2-36ubuntu11.3

I don't know if there are any Ubuntu specific patches in there, I'd have 
to check but.....