ZFS on entire disks setup

[O. Hartmann]

Olivier Smedts wrote:
> 2009/9/26 krad <kraduk at googlemail.com>:
>> 2009/9/26 Stefan Bethke <stb at lassitu.de>
>>
>>> Am 26.09.2009 um 13:39 schrieb Dmitry Morozovsky:
>>>
>>> �Dear colleagues,
>>>> is there a way to configure ZFS-only setup without partitions?
>>>>
>>>> I tried to reproduce the trick with `skip=1 seek=1024', and have
>>>> loot/loader
>>>> running, but it does not see the pool.
>>>>
>>> This sequence is working for me:
>>> dd if=/boot/zfsboot of=/dev/da0 count=1
>>> dd if=/boot/zfsboot of=/dev/da0 skip=1 seek=1024
>>> zpool create zroot /dev/da0
>>> zpool set bootfs=zroot zroot
>>> cd /usr/src && make installworld installkernel distribution DESTDIR=/zroot
>>> cp /boot/loader.conf /zroot/boot/loader.conf
>>> cp /etc/rc.conf /zroot/etc/
>>> touch /zroot/etc/fstab
>>> echo 'zfs_load="YES"' >>/zroot/boot/loader.conf
>>> echo 'vfs.root.mountfrom="zfs:zroot"' >>/zroot/boot/loader.conf
>>> zpool export zroot
>>> zpool import zroot
>>> cp /boot/zfs/zpool.cache /zroot/boot/zfs/
>>> zfs set mountpoint=legacy zroot
>>>
>>> ... except that it doesn't anymore. �I saw this working about two months
>>> ago, but now it fails to mount root. �Verbose boot doesn't give any
>>> indication why ZFS can't find the pool.
>>>
>>>
>>> Stefan
>>>
>>> --
>>> Stefan Bethke <stb at lassitu.de> � Fon +49 151 14070811
>>>
>>>
>>>
>>>
>>>
>>> _______________________________________________
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>>>
>>
>> have the performance issues with zvols been fixed. I remember a while ago it
>> wasn't a good idea to run swap on a zvol. This is why i left a partition
>> free for swap
> 
> Still not a good idea, I've got lockups for many minutes when
> consuming heavy memory ressources, for example when doing a "make" in
> ports/emulators/virtualbox with firefox and amarok opened. I've got
> 2GB RAM on amd64.
> 
>> _______________________________________________
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>>
> 


I see those lockups on three boxes when compiling or having heavy disk
I/O on three different boxes, one (private) UP amd64 with 2GB, one SMP
4-core box amd64 with 8 GB and one SMP 8-core box amd64 SMP with 16 GB
RAM. It doesn't matter what filesystem is involved, either UFS2 or ZFS!
When compiling world AND compiling KDE4-libs or GCC44/GCC45, even those
boxes with 8 or 16 GB of RAM and 4 or 8 cores have painful performance
issues (locking for several seconds, no response over network or, if
enabled and running, X11/mouse gets jumpy and completely inresponsible,
quite near useless that moment).
I doubt that ZFS causes the problem, it sounds more like a scheduling
problem introduced with the early 8.0 (since 7.2 ran fluently on
mentioned boxes, but have had other issues).
All three boxes under my supervision run FreeBSD 8.0-RC1/amd64 and they
all use UFS2-partioned harddrives for OS separated from data drives
using ZFS-only. Even copying/backup data from /home on a ZFS volume to
another ZFS volume with compression enabled (on another SATA-II drive)
does not reveale those issues on the 2GB, UP amd64 box as showed when
the box is under heavy load when the GCC compiler is running or PERL
scripts are doing their duties.


Regards,
Oliver