A plex is on top of aggr, raid groups reside on top of plexes, volumes reside in raid groups. There can be several raid groups to a single plex. You can only have 1 mirror of a plex in ONTAP 7.
To view plex info:
aggr status -v
Aggr State Status Options
aggr0 online raid0, aggr root, diskroot, nosnap=off,
raidtype=raid0, raidsize=8,
ignore_inconsistent=off,
snapmirrored=off,
resyncsnaptime=60,
fs_size_fixed=off,
snapshot_autodelete=on,
lost_write_protect=on
Volumes: vol0
Plex /aggr0/plex0: online, normal, active
RAID group /aggr0/plex0/rg0: normal
vol status -v
Volume State Status Options
vol0 online raid0, flex root, diskroot, nosnap=off,
nosnapdir=off, minra=off,
no_atime_update=on, nvfail=off,
ignore_inconsistent=off,
snapmirrored=off,
create_ucode=on,
convert_ucode=on,
maxdirsize=2621,
schedsnapname=ordinal,
fs_size_fixed=off,
compression=off,
guarantee=volume, svo_enable=off,
svo_checksum=off,
svo_allow_rman=off,
svo_reject_errors=off,
no_i2p=off,
fractional_reserve=100,
extent=off,
try_first=volume_grow,
read_realloc=off,
snapshot_clone_dependency=off
Containing aggregate: 'aggr0'
Plex /aggr0/plex0: online, normal, active
RAID group /aggr0/plex0/rg0: normal
Snapshot autodelete settings for vol0:
state=off
commitment=try
trigger=volume
target_free_space=20%
delete_order=oldest_first
defer_delete=user_created
prefix=(not specified)
destroy_list=none
Volume autosize settings:
state=off
From man na_aggr (maybe this will help):
A plex is a physical copy of the WAFL storage within the aggregate. A mirrored aggregate consists of two plexes; unmirrored aggregates contain a single plex. In order to create a mirrored aggregate, you must have a filer configuration that supports RAID-level mirroring. When mirroring is enabled on the filer, the spare disks are divided into two disk pools. When an aggregate is created, all of the disks in a single plex must come from the same disk pool, and the two plexes of a mirrored aggregate must consist of disks from separate pools, as this maximizes fault isolation. This policy can be overridden with the -f option to aggr create, aggr add and aggr mirror, but it is not recommended.
A plex may be online or offline. If it is offline, it is not available for read or write access. Plexes can be in combinations of the following states:
normal All RAID groups in the plex are functional.
failed At least one of the RAID groups in the plex has failed.
empty The plex is part of an aggregate that is being created, and one or more of the disks targeted to the aggregate need to be zeroed before being added to the plex.
active The plex is available for use.
inactive
The plex is not available for use.
resyncing
The plex's contents are currently out of date and are in the process of being resynchronized with the contents of the other plex of the aggregate (applies to mirrored aggregates only).
adding disks
Disks are being added to the plex's RAID group(s).
out-of-date
This state only occurs in mirrored aggregates where one of the plexes has failed. The non-failed plex will be in this state if it needed to be resynchronized at the time the other plex failed.
A plex is named using the name of the aggregate, a slash character delimiter, and the name of the plex. The system automatically selects plex names at creation time. For example, the first plex created in aggregate aggr0 would be aggr0/plex0.
The disks in a plex are not permitted to span disk pools. This behavior can be overridden with the -f flag when used together with the -d argument to list disks to add. The -f flag, in combination with -d, can also be used to force adding disks that have a rotational speed that does not match that of the majority of existing disks in the aggregate.
The -m option can be used to specify that the new aggregate be mirrored (have two plexes) upon creation. If this option is given, then the indicated disks will be split across the two plexes. By default, the new aggregate will not be mirrored.
If you use the -d disk1 [ disk2 ... ] argument, the filer creates the aggregate with the specified spare disks disk1, disk2, and so on. You can specify a space-separated list of disk names. Two separate lists must be specified if the new aggregate is mirrored. In the case that the new aggregate is mirrored, the indicated disks must result in an equal number of disks on each new plex.
The disks in a plex are not permitted to span spare pools. This behavior can be overridden with the -f option. The same option can also be used to force using disks that do not have matching rotational speed. The -f option has effect only when used with the -d option specifying disks to use.
