zfs discuss - Sep 2007 - ZFS mirror with internal and external disks

I am trying to use a ZFS mirror to safeguard against hard disk failure in the
following manner. My data ZFS pool resides in slice s7 of the laptop internal
disk (c1d0s7). I have an external disk which slice s7 I have made exactly the
same size of c1d0s7 above, then I have attached it to the pool as a mirror.
My aim is to be able to use the internal disk only while I am working and in the
evening when I get home I want to connect the external disk and have it
"synchronize"  with the internal disk, transparently backing up my
data so that if I somehow lose the internal disk I still have one (reasonably
up-to-date) copy of the data.

Two questions regarding this approach:

1. Which is the correct way to connect the external disk? I have noticed that if
I import the pool without the external disk connected, zpool status will mark
the device as unavailable, unless I offline it before exporting the pool.
However, if I import the pool with the external disk offline, when reconnecting
the external disk, resilver still says there are lots of checksum errors, which
makes me uncomfortable as to whether the external disk is an exact copy of the
internal one or not. Should I use attach/detach instead of offline/online? By
the way, when the external disk is marked as offline and I reconnect it, it goes
automatically to online, without waiting for me to issue zpool online. Is that
right?

2. If I detach the external disk, or if the internal disk crashes, can I import
the pool in another machine with only the external disk?

Thanks in advance.

-- Doug
 
 
This message posted from opensolaris.org

I''m afraid I asked a very stupid question...
 
 
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