Managing Permanent and Transient Storage

Use VOLUTIL, the disk management utility, to allocate permanent storage and transient storage on system volumes. The NEWVOL command configures permanent and transient storage on system volumes, and ALTERVOL changes the allocation.

Permanent storage is disk space used on both system and nonsystem volumes for permanent structures such as files (permanent and temporary), the label table, and the free space map. Permanent structures are those that do not need to be re-created when the system is rebooted. Nonsystem volumes may use only permanent storage.
Transient storage is used on system volumes for structures such as virtual memory and other temporary operating system data structures. Transient structures need to be re-created when the system is rebooted.

In the figure below, permanent storage is visualized as filling in from the bottom toward its maximum. Transient storage is visualized in the figure as filling in from the top toward its maximum.

Figure 9-8 Permanent and Transient Storage

In this figure, permanent and transient storage is limited to 75 percent of the total storage space. Permanent storage already occupies 20 percent of the total, and transient storage fills 50 percent. Permanent storage theoretically could take up another 55 percent, but only 30 percent of the total storage space remains free. So, permanent storage is limited to 30 percent more. Transient storage can take up another 25 percent. In this case, 5 percent of the space would remain free.




	NOTE: You should always configure nonsystem volumes at 100 percent permanent, which is the default. Since the system does not put transient objects on nonsystem volumes, any transient storage that is configured cannot be used.

To configure disk storage

Use the NEWVOL command to configure disk storage. For example, to configure 65 percent permanent storage and 65 percent transient storage on the system volume MEMBER4, enter:

   volutil:NEWVOL VNAME=MPEXL_SYSTEM_VOLUME_SET:MEMBER4 PERM=65 TRANS=65




	NOTE: The operating system limits the changes that can be made to transient storage space on LDEV 1, the system master volume. It is not recommended that transient space be modified for LDEV 1, but if you must do so, plan carefully. For LDEV1, the default value for transient space is 75 percent and the default value for permanent storage is 75 percent.

To change the disk storage

Use the ALTERVOL command to change the permanent and transient disk space allocation for a particular volume.

To use ALTERVOL, at the volutil: prompt, enter:

   volutil:ALTERVOL sname:vname percentperm percenttrans

ALTERVOL has the following parameters:

ALTERVOL { [VNAME] = sname:vname} [ [PERM] = percentperm] [ [TRANS] = percenttrans]

For example, to change the permanent and transient storage allocation on the volume SAMPLE_VOL in the volume set SAMPLE_SET to 100 percent, enter:

   volutil:ALTERVOL SAMPLE_SET:SAMPLE_VOL 100 100

Managing Permanent and Transient Storage

Technical documentation

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To configure disk storage

To change the disk storage