zfs discuss - Mar 2009 - ZFS and the copies property

Hello,

 

I have a question about using the `copies` option in zfs.

 

If I were to make a non-redundant zpool of say 3 hard drives, but set
the `copies` option to something like 2 or 3, would that protect me in
the event of a hard drive failure?  Or would raidz be the only way to
really protect against the loss of a hard drive?

 

 

 

 

Thank you,

 

 

Robert Parkhurst

Systems Administrator

Gresham Enterprise Storage

greshamstorage.com

O:  512.407.2694

M:  512.698.7419

 

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Robert Parkhurst wrote:
> I have a question about using the `copies` option in zfs.
> 
> If I were to make a non-redundant zpool of say 3 hard drives, but set 
> the `copies` option to something like 2 or 3, would that protect me in 
> the event of a hard drive failure? 
No it won''t because if a drive completely fails then the pool
won''t
import.  The copies option is to help with partial failures of a drive 
but doesn''t help with complete failure if there is no other redundancy 
in the pool level devices.
> Or would raidz be the only way to 
> really protect against the loss of a hard drive?
With only 3 disks then raidz is your only choice but note that you
can''t
boot from a raidz or a stripe only mirrors (1 or more sides) are 
supported for booting from.

-- 
Darren J Moffat