Hello Kory,
Tuesday, January 15, 2008, 1:46:40 PM, you wrote:
KW> What would be the commands for the three way mirror or an example
KW> of what your describing. I thought the 200gb would have to be the
KW> same size to attach to the existing mirror and you would have to
KW> attach two LUN disks vs one LUN. Once it attaches it
KW> automatically reslivers or syncs the disk then if I wanted to I
KW> could remove the two 73 GB disks or still keep them in the pool
KW> and expand the pool later if I want?
KW>
KW>
No, if you are attaching another disk to mirror it doesn't have to be
the same size - it can be bigger, however you won't be able to see all
the space from the disk as long as it forms N-way mirror with smaller
devices.
And yes, if you add (attach) another disk to a mirror it will
automatically resilver, and you can keep previous two disks - you will
get 3-way mirror (you can create N-way mirror in general).
Once you happy new disk is working properly you just remove (detach)
two old disk and your pool automatically grows.
Keep in mind that the reverse is not possible (yet).
Below example showing your case.
# mkfile 512m disk1
# mkfile 512m disk2
# mkfile 1024m disk3
# zpool create test mirror /root/disk1 /root/disk2
# zpool status
pool: test
state: ONLINE
scrub: none requested
config:
NAME STATE READ WRITE CKSUM
test ONLINE 0 0 0
mirror ONLINE 0 0 0
/root/disk1 ONLINE 0 0 0
/root/disk2 ONLINE 0 0 0
# cp -rp /lib/ /test/
# zpool list
NAME SIZE USED AVAIL CAP HEALTH ALTROOT
test 504M 83.2M 421M 16% ONLINE -
#
# zpool attach test /root/disk2 /root/disk3
# zpool status
pool: test
state: ONLINE
status: One or more devices is currently being resilvered. The pool will
continue to function, possibly in a degraded state.
action: Wait for the resilver to complete.
scrub: resilver in progress, 69.59% done, 0h0m to go
config:
NAME STATE READ WRITE CKSUM
test ONLINE 0 0 0
mirror ONLINE 0 0 0
/root/disk1 ONLINE 0 0 0
/root/disk2 ONLINE 0 0 0
/root/disk3 ONLINE 0 0 0
errors: No known data errors
#
Waiting for a re-silvering to complete.
# zpool status
pool: test
state: ONLINE
scrub: resilver completed with 0 errors on Tue Jan 15 14:41:13 2008
config:
NAME STATE READ WRITE CKSUM
test ONLINE 0 0 0
mirror ONLINE 0 0 0
/root/disk1 ONLINE 0 0 0
/root/disk2 ONLINE 0 0 0
/root/disk3 ONLINE 0 0 0
errors: No known data errors
#
# zpool list
NAME SIZE USED AVAIL CAP HEALTH ALTROOT
test 504M 83.3M 421M 16% ONLINE -
#
# zpool detach test /root/disk1
# zpool detach test /root/disk2
# zpool status
pool: test
state: ONLINE
scrub: resilver completed with 0 errors on Tue Jan 15 14:41:13 2008
config:
NAME STATE READ WRITE CKSUM
test ONLINE 0 0 0
/root/disk3 ONLINE 0 0 0
errors: No known data errors
#
# zpool list
NAME SIZE USED AVAIL CAP HEALTH ALTROOT
test 1016M 83.2M 933M 8% ONLINE -
#
so we've migrated data from a 2-way mirror to a just one disk, live
without unmounting file systems, etc. If your 3rd disk is already
protected if you follow above procedure you will have a protected
configuration all the time (however at the end you relay on disk3
built-in redundancy).
--
Best regards,
Robert Milkowski mailto:[EMAIL PROTECTED]
http://milek.blogspot.com
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