ZFS NAS configuration question

[Miroslav Lachman]

Daniel O'Connor wrote:
> On Tue, 2 Jun 2009, Dan Naumov wrote:
> 
>>USB root partition for booting off UFS is something I have
>>considered. I have looked around and it seems that all the "install
>>FreeBSD onto USB stick" guides seem to involve a lot of manual work
>>from a fixit environment, does sysinstall not recognise USB drives as
>>a valid disk device to parition/label/install FreeBSD on? If I do go
>>with an USB boot/root, what things I should absolutely keep on it and
>>which are "safe" to move to a ZFS pool? The idea is that in case my
>>ZFS configuration goes bonkers for some reason, I still have a fully
>>workable singleuser configuration to boot from for recovery.
> 
> 
> It should see them as SCSI disks, note that if you plug them in after 
> the installer boots you will need to go into Options and tell it to 
> rescan the devices.
> 
> 
>>I haven't really used USB flash for many years, but I remember when
>>they first started appearing on the shelves, they got well known for
>>their horrible reliability (stick would die within a year of use,
>>etc). Have they improved to the point of being good enough to host a
>>root partition on, without having to setup some crazy GEOM mirror
>>setup using 2 of them?
> 
> 
> I would expect one to last a long time if you only use it for /boot and 
> use ZFS for the rest (or even just moving /var onto ZFS would save 
> heaps of writes).

I am using this setup (booting from USB with UFS) in our backup storage 
server with FreeBSD 7.2 + ZFS.
2GB USB flash disk contains normal installation of the whole system, but 
is set to read only in fstab. ZFS is used for /tmp /var /usr/ports 
/usr/src /usr/obj and storage.

root filesystem is remounted read write only for some configuration 
changes, then remounted back to read only.

Miroslav Lachman


# df -h
Filesystem                       Size  Used  Avail Capacity  Mounted on
/dev/ufs/2gLive                  1.6G  863M   642M    57%    /
devfs                            1.0K  1.0K     0B   100%    /dev
tank                             1.1T  128K   1.1T     0%    /tank
tank/system                      1.1T  128K   1.1T     0%    /tank/system
tank/system/usr                  1.1T  128K   1.1T     0% 
/tank/system/usr
tank/system/tmp                  1.1T  128K   1.1T     0%    /tmp
tank/system/usr/obj              1.1T  128K   1.1T     0%    /usr/obj
tank/system/usr/ports            1.1T  218M   1.1T     0%    /usr/ports
tank/system/usr/ports/distfiles  1.1T  108M   1.1T     0% 
/usr/ports/distfiles
tank/system/usr/ports/packages   1.1T  125M   1.1T     0% 
/usr/ports/packages
tank/system/usr/src              1.1T  171M   1.1T     0%    /usr/src
tank/system/var                  1.1T  256K   1.1T     0%    /var
tank/system/var/db               1.1T  716M   1.1T     0%    /var/db
tank/system/var/db/pkg           1.1T  384K   1.1T     0%    /var/db/pkg
tank/system/var/log              1.1T   45M   1.1T     0%    /var/log
tank/system/var/run              1.1T  128K   1.1T     0%    /var/run
tank/vol0                        2.6T  1.5T   1.1T    57%    /vol0
tank/vol0/mon                    1.1T  128K   1.1T     0%    /vol0/mon

(some filesystems are using compression, that's why ports and var are 
splitted in to more filesystems)