Walkthrough
In the following post, the Data ONTAP 8.1.2 7-Mode
Simulator is used to demonstrate how to configure SyncMirror.
The starting point is 2 shelves of 14 virtual disks. One
shelf is going to act as disk Pool0 containing one half of the mirrored
aggregate; another shelf as disk Pool1 containing the other half of the
mirrored aggregate.
To find the System ID:
NTAP> sysconfig
To show disk ownership and pools:
NTAP> disk show -v
Out of the box, the SIM has 14 disks are assigned to
Pool0 - that is all disks v5.*. To assign 14 disks to Pool1:
NTAP> disk assign -p 1
-s 4055372815 v4.*
{Where 4055372815
is the System ID found from sysconfig}
NOTE: For a
physical HA Pair: “When assigning disk ownership, always assign all disks to
the same loop or stack to the same storage system and pool as well as to the
same adaptor.”
The SyncMirror license must be enabled to create a
mirrored aggregate; add the license and reboot to enable:
NTAP> license add
RIQTKCL #syncmirror_local
NTAP> reboot
NOTE: For a
physical HA Pair: Use cf takeover and cf giveback to non-disruptively reboot
both nodes in the HA Pair.
To display disks per pool with their physical size:
NTAP> aggr status -r
The simulator starts off with 3 disks in aggr0 in Pool0
containing the root volume, this leaves 11 disks spare in Pool0. To create an
11 disk mirrored aggregate
NTAP> aggr create
syncmirror_aggr1 -m -n 22@1027m
The output of the above provides the next command:
NTAP> aggr create
syncmirror_aggr1 -m -d v5.32 v5.29 v5.28 v5.27 v5.26 v5.25 v5.24 v5.22 v5.21
v5.20 v5.19 -d v4.27 v4.26 v4.25 v4.24 v4.22 v4.21 v4.20 v4.19 v4.18 v4.17
v4.16
NTAP> aggr status
Aggr State Status
Options
syncmirror_aggr1 online raid_dp, aggr
mirrored
64-bit
aggr0 online raid_dp, aggr root
64-bit
The next bit is where we move the root volume to our
mirrored aggregate; destroy aggr0; zero spares (the 3 disks used by aggr0 need
zeroing); add four more disks to the mirrored aggregate (2 per pool), leaving
one spare per pool; run a volume reallocate on vol0 (see here
for why.)
df -h vol0
vol create vol0new
syncmirror_aggr1 808m
ndmpd on
ndmpcopy /vol/vol0 /vol/vol0new
vol options vol0new root
reboot
{System reboots}
vol status
vol offline vol0
vol destroy vol0
aggr status
aggr offline aggr0
aggr destroy aggr0
disk zero spares
vol rename vol0new vol0
aggr status -r
aggr add syncmirror_aggr1 -d
v4.28 v4.29 -d v5.16 v5.17
reallocate -f -p /vol/vol0
reallocate status
NOTE: For a physical
Metrocluster environment - where you would have the cf and cf_remote licenses
installed - having the root volume on a mirrored aggregate is a requirement. Otherwise
the system would error with “Root volume is not mirrored. A takeover of this
filer may not be possible in case of a disaster”.
NOTE 2: There are a
couple of (pretty obvious) rules for adding disks to a mirrored aggregate
“1) The number of
disks must be an even number and must be evenly divided between the two
plexes.”
“2) Each plex must
have disks from different pools and have equivalent bytes-per-sector sizes.”
Image: How Disk
Pools and Plexes Make up a SyncMirror Mirrored Aggregate
APPENDIX:
Output of vol status, aggr status, aggr status -r
ntap>
vol status
Volume State Status Options
vol0 online raid_dp, flex root
mirrored
64-bit
ntap>
aggr status
Aggr State Status Options
syncmirror_aggr1
online raid_dp, aggr root
mirrored
64-bit
ntap>
aggr status -r
Aggregate
syncmirror_aggr1 (online,
raid_dp, mirrored)
(block checksums)
Plex /syncmirror_aggr1/plex0 (online, normal,
active, pool0)
RAID group /syncmirror_aggr1/plex0/rg0 (normal, block
checksums)
RAID Disk Device Pool Phys(MB)
--------- ------ ---- --------
dparity
v5.32 0 1027
parity
v5.29 0 1027
data
v5.28 0 1027
data v5.27
0 1027
data
v5.26 0 1027
data
v5.25 0 1027
data
v5.24 0 1027
data
v5.22 0 1027
data
v5.21 0 1027
data
v5.20 0 1027
data
v5.19 0 1027
data
v5.16 0 1027
data
v5.17 0 1027
Plex /syncmirror_aggr1/plex1 (online, normal,
active, pool1)
RAID group /syncmirror_aggr1/plex1/rg0 (normal, block
checksums)
RAID Disk Device Pool Phys(MB)
--------- ------ ---- --------
dparity
v4.27 1 1027
parity
v4.26 1 1027
data
v4.25 1 1027
data
v4.24 1 1027
data
v4.22 1 1027
data
v4.21 1 1027
data
v4.20 1 1027
data
v4.19 1 1027
data
v4.18 1 1027
data
v4.17 1 1027
data
v4.16 1 1027
data
v4.28 1 1027
data
v4.29 1 1027
Pool1
spare disks
RAID
Disk Device Pool Phys(MB)
--------- ------
---- --------
spare v4.32 1 1027
Pool0
spare disks
RAID
Disk Device Pool Phys(MB)
--------- ------
---- --------
spare v5.18 0 1027
CONTINUED IN PART 2...
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