zfs discuss - Aug 2006 - Newbie questions about drive problems

Hi,

I''m a newbie at ZFS but I have some questions: 

I have 3 drives.
The first one will be the primary/boot drive under UFS. The 2 others will become
a mirrored pool with ZFS.
Now, I have problem with the boot drive (hardware or software), so all the data
on my mirrored pool are ok?
How can I restore this pool? When I create the pool, do I need to save the
properties?


What happend when a drive crash when ZFS write some data on a raidz pool?
Do the pool go to the degraded state or faulted state?
 
 
This message posted from opensolaris.org

Hi,
> I have 3 drives.
> The first one will be the primary/boot drive under UFS. The 2 others will
become a mirrored pool with ZFS.
> Now, I have problem with the boot drive (hardware or software), so all the
data on my mirrored pool are ok?
> How can I restore this pool? When I create the pool, do I need to save the
properties?
All metadata for the pool is stored inside the pool. If the boot disk fails in
any way, all pool data is safe.

Worst case might be that you have to reinstall everything on the boot disk.
After that, you just say "zfs import" to get your pool back and
everything
will be ok.
> What happend when a drive crash when ZFS write some data on a raidz pool?
If the crash occurs in the middle of a write operation, then the new data
blocks will not be valid. ZFS will then revert back to the state before
writing the new set of blocks. Therefore you''ll have 100% data
integrity
but of course the new blocks that were written to the pool will be lost.
> Do the pool go to the degraded state or faulted state?
No, the pool will come up as online. The degraded state is only for devices
that aren''t accessible any more and the faulted state is for pools that
do
not have enough valid devices to be complete.

Hope this helps,
   Constantin

-- 
Constantin Gonzalez                            Sun Microsystems GmbH, Germany
Platform Technology Group, Client Solutions                http://www.sun.de/
Tel.: +49 89/4 60 08-25 91                   http://blogs.sun.com/constantin/

Thanks

Now, I don''t have any worry to migrate to ZFS.
> > I have 3 drives.
> > The first one will be the primary/boot drive under
> UFS. The 2 others will become a mirrored pool with
> ZFS.
> > Now, I have problem with the boot drive (hardware
> or software), so all the data on my mirrored pool are
> ok?
> > How can I restore this pool? When I create the
> pool, do I need to save the properties?
> 
> All metadata for the pool is stored inside the pool.
> If the boot disk fails in
> any way, all pool data is safe.
> 
> Worst case might be that you have to reinstall
> everything on the boot disk.
> After that, you just say "zfs import" to get your
> pool back and everything
> will be ok.
> 
> > What happend when a drive crash when ZFS write some
> data on a raidz pool?
> 
> If the crash occurs in the middle of a write
> operation, then the new data
> blocks will not be valid. ZFS will then revert back
> to the state before
> writing the new set of blocks. Therefore you''ll have
> 100% data integrity
> but of course the new blocks that were written to the
> pool will be lost.
> 
> > Do the pool go to the degraded state or faulted
> state?
> 
> No, the pool will come up as online. The degraded
> state is only for devices
> that aren''t accessible any more and the faulted state
> is for pools that do
> not have enough valid devices to be complete.
> 
> Hope this helps,
>    Constantin
 
 
This message posted from opensolaris.org