HP 3PAR Operating System Software - Manual (Page 260)

logical disks are removed from the CPG. This is permitted only when the existing snapshot
logical disks are exclusively used by the volumes specified in this option.
-snp_aw
Indicates a snapshot space allocation warning. Through this option you can generate a warning
alert when the snapshot space of the virtual volume exceeds the indicated percentage of
the virtual volume size.
-snp_al
Indicates a snapshot space allocation limit. The snapshot space of the virtual volume is prevented
from growing beyond the indicated percentage of the virtual volume size.
–pol [,...]
Specifies the policy is implemented by a virtual volume. Valid policies are as follows:
•
stale_ss - Specifies that invalid (stale) snapshot volumes are permitted. Failures to update
snapshot data occur when there is not sufficient administration or snapshot space. Failures
to update snapshot data does not affect the write to the base volume. However, the snapshot
is considered invalid.
•
no_stale_ss - Specifies that stale snapshot volumes are not permitted. A failure to
update a snapshot is considered a failure to write to the base volume. Existing stale
snapshots remain stale.
•
one_host - Constrains the export of a volume to one host or one host cluster (when cluster
names may be used as a host name).
•
no_one_host - This policy should only be used when exporting a virtual volume to multiple
hosts for use by a cluster-aware application, or when “port presents” VLUNs are used.
This is the default policy setting.
•
tp_bzero - Specifies that if a host write results in the allocation of a new data page that
is only partially filled by the host write, then a zero-fill is performed on the unwritten portion
of the data page to ensure that the host cannot read data from deleted volumes or snapshot.
The default allocation page size is 16 KB.
•
no_tp_bzero - Specifies that the zero-fill operation is bypassed on the allocation of
partially written data pages.
•
zero_detect - Enables the HP 3PAR Storage System to scan for zeros in the incoming
write data. When used during a physical copy to a Thinly Provisioned Virtual Volume
(TPVV) avoids allocating space for blocks containing zero. When used with a Thin
Persistence license, reclaims allocated space when zero blocks are written to a TPVV. This
policy is applicable for base TPVVs.
•
no_zero_detect - Disables the HP 3PAR Storage System to scan for zeros in the incoming
write data to reclaim allocated space on the volume.
Multiple policies can be specified and are separated with commas. If a policy is not specified,
the policy defaults to stale_ss.
The following options can only be used on Thinly Provisioned Virtual Volumes (TPVVs):
-usr_aw
This option returns a user space allocation warning. It generates a warning alert when the user
space of the TPVV exceeds the specified percentage of the virtual volume size.
-usr_al
This option returns the user space allocation limit. The user space of the TPVV is prevented from
growing beyond the indicated percentage of the virtual volume size. After this size is reached,
any new writes to the virtual volume will fail.
-spt
Defines the virtual volume geometry sectors per track value that is reported to the hosts through
the SCSI mode pages. The valid range is from 4 to 8192. The default value is 304.
260 The Remote Copy Commands