You can define volume allocation attributes so they can be reused in subsequent operations. These attributes are called persistent attributes, and they are stored in a set of hidden volume tags. The persist attribute determines whether an attribute persists, and how the current command might use or modify preexisting persisted attributes. You can specify persistence rules in defaults files, in rules, or on the command line. For more information, see the vxassist manual page.
To illustrate how persistent attributes work, we'll use the following vxsf_rules
file. It contains a rule, rule1, which defines the mediatype attribute. This rule also uses the persist attribute to make the mediatype attribute persistent.
# cat /etc/default/vxsf_rules volume rule rule1 { mediatype:ssd persist=extended }
The following command confirms that LUNs ibm_ds8x000_0266 and ibm_ds8x000_0268 are solid-state disk (SSD) devices.
# vxdisk listtag DEVICE NAME VALUE ibm_ds8x000_0266 vxmediatype ssd ibm_ds8x000_0268 vxmediatype ssd
The following command creates a volume, vol1, in the disk group dg3. rule1 is specified on the command line, so those attributes are also applied to vol1.
# vxassist -g dg3 make vol1 100m rule=rule1
The following command shows that the volume vol1 is created off the SSD device ibm_ds8x000_0266 as specified in rule1.
# vxprint -g dg3 TY NAME ASSOC KSTATE LENGTH PLOFFS STATE TUTIL0 PUTIL0 dg dg3 dg3 - - - - - - dm ibm_ds8x000_0266 ibm_ds8x000_0266 - 2027264 - - - - dm ibm_ds8x000_0267 ibm_ds8x000_0267 - 2027264 - - - - dm ibm_ds8x000_0268 ibm_ds8x000_0268 - 2027264 - - - - v vol1 fsgen ENABLED 204800 - ACTIVE - - pl vol1-01 vol1 ENABLED 204800 - ACTIVE - - sd ibm_ds8x000_0266-01 vol1-01 ENABLED 204800 0 - - -
The following command displays the attributes that are defined in rule1.
# vxassist -g dg3 help showattrs rule=rule1 alloc=mediatype:ssd persist=extended
If no persistent attributes are defined, the following command grows vol1 on hard disk drive (HDD) devices. However, at the beginning of this section, mediatype:ssd was defined as a persistent attribute. Therefore, the following command honors this original intent and grows the volume on SSD devices.
# vxassist -g dg3 growby vol1 1g
The following vxprint command confirms that the volume was grown on SSD devices.
# vxprint -g dg3 TY NAME ASSOC KSTATE LENGTH PLOFFS STATE TUTIL0 PUTIL0 dg dg3 dg3 - - - - - - dm ibm_ds8x000_0266 ibm_ds8x000_0266 - 2027264 - - - - dm ibm_ds8x000_0267 ibm_ds8x000_0267 - 2027264 - - - - dm ibm_ds8x000_0268 ibm_ds8x000_0268 - 2027264 - - - - v vol1 fsgen ENABLED 2301952 - ACTIVE - - pl vol1-01 vol1 ENABLED 2301952 - ACTIVE - - sd ibm_ds8x000_0266-01 vol1-01 ENABLED 2027264 0 - - - sd ibm_ds8x000_0268-01 vol1-01 ENABLED 274688 2027264 - - -