emc powerpath powermt cheatsheet

powermt in a shutshell
Usage:
powermt [class=]
powermt check [force] [hba=|all] [dev=|all]
powermt check_registration
powermt config
powermt display [ports] [dev=|all] [every=]
powermt display options
powermt display paths [every=]
powermt display unmanaged
powermt manage {dev= | class={invista | hitachi | hpxp | ess | hphsx}}
powermt unmanage {dev= | class={invista | hitachi | hpxp | ess | hphsx}}
powermt load [file=]
powermt release
powermt remove [force] hba=|all | dev=|all
powermt restore [hba=|all] [dev=|all]
powermt save [file=]
powermt set mode=active|standby [hba=|all] [dev=|all]
powermt set periodic_autorestore=on|off
powermt set policy={ad|bf|co|lb|li|nr|re|rr|so} [dev=|all]
powermt set priority= [dev=|all]
powermt update lun_names
powermt version

usage examples：
powermt display dev=all
powermt check_registration
powermt watch


An advance usage is as follows:

powermt set policy=policy [class={symm|clariion|hitachi|hpxp|ess|all}]
[dev=device|all]

powermt set policy sets the load balancing and failover
policy for PowerPath devices.

Arguments

policy=policy
Sets the load balancing and failover policy to one
of the following values:

ad Adaptive. I/O requests are assigned to paths
based on an algorithm that takes into account
path load and logical device priority. This
policy is valid only for Hitachi Lightning,
HP xp, and IBM ESS storage systems and is the
default policy for them on platforms with a
valid PowerPath license.

bf Basic failover. Load balancing is not in
effect. I/O routing on failure is limited to
one HBA and one port on each storage
processor. When a host boots, it designates
one path (through one interface) for all I/O.
If an I/O is issued to a logical device that
cannot be reached via that path (that is, the
I/O cannot reach that logical device through
the device's assigned interface), a trespass
is performed: the logical device is assigned
to the other interface.

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User Commands powermt(1)

This policy protects against SP and back-end
failures and allows non-disruptive upgrades
to work when running PowerPath without a
license key. It does not protect against HBA
or host loop failures.

This policy is valid only for CLARiiON
storage systems and is the default policy for
them on platforms without a valid PowerPath
license.

co CLARiiON optimization (listed in powermt
display output as CLAROpt). I/O requests are
assigned to paths based on an algorithm that
takes into account path load and the priority
you set with powermt set policy.

This policy is valid only for CLARiiON
storage systems and is the default policy for
them on platforms with a valid PowerPath
license.

lb Least blocks. Load balance is based on the
number of blocks in the pending I/Os. I/O
requests are assigned to the path with the
smallest burden in terms of blocks,
regardless of the number of requests
involved.

li Least I/Os. Load balance is based on the
number of pending I/Os. I/O requests are
assigned to the path with the smallest number
of requests, regardless of total block
volume.

nr No redirect. Neither load balancing nor
failover is in effect. If nr is set on a
failed path and a native device is used, I/O
errors will occur when I/O is directed to
that path. If one or more paths is failed and
nr is set, data I/O errors can occur.

This policy is valid only for Symmetrix,
Hitachi Lightning, HP xp, and IBM ESS storage
systems and is the default policy for them on
platforms without a valid PowerPath license.

re Request. For native devices, uses the path
that would have been used if PowerPath were
not installed. For pseudo devices, uses one
arbitrary path for all I/O. For all devices,
failover is in effect, but load balancing is

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User Commands powermt(1)

not.

rr Round robin. I/O requests are assigned to
each available path in rotation.

so Symmetrix optimization (listed in powermt
display output as SymmOpt). I/O requests are
assigned to paths based on an algorithm that
takes into account path load and the priority
you set with powermt set policy.

This policy is valid only for Symmetrix
storage systems and is the default policy for
them on platforms with a valid PowerPath
license.