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5.4. Creating a Configuration File for a New Volume

A pool configuration file is used as input to the pool_tool command when creating or growing a pool volume. The configuration file defines the name and layout of a single pool volume. Refer to Figure 5-1 for the pool configuration file format. Refer to Table 5-9 for descriptions of the configuration file keywords and variables.

An arbitrary name can be used for a pool configuration file; however, for consistency, it is recommended that you name the file using the pool name followed by the .cfg extension (poolname.cfg). For example, the pool configuration file for a pool named pool0 would be defined in configuration file pool0.cfg.

Before creating a configuration file, you can check to see what devices are available by using the pool_tool command with the -s option.

poolname name
minor number
subpools number
subpool id stripe devices [type] 
pooldevice subpool id device

Figure 5-1. File Structure: Pool Configuration File

File Line and KeywordVariableDescription
poolnamenameThe name of the pool device that appears in the /dev/pool/ directory.
minornumberAssigns a device minor number (0 to 64) to a pool. If number is specified as 0 (or if the minor line is omitted), the minor number of the pool is assigned dynamically. The default value is 0.
subpoolsnumberRepresents the total number of subpools in the pool. The number value should be set to a value of 1 unless special data or journal subpools are used.
subpoolid stripe devices [type]

The details of each subpool:
id is the subpool identifier. Number the subpools in order beginning with 0.
stripe is the stripe size in sectors (512 bytes per sector) for each device. A value of 0 specifies no striping (concatenation).
devices specifies the number of devices in the subpool.
type is optional and specifies the label type to attach to the subpool. Values of gfs_data or gfs_journal are acceptable. The default value is gfs_data.

pooldevicesubpool id device

Adds a storage device to a subpool:
subpool specifies the subpool identifier to which the device is to be added.
id is the device identifier. Number the devices in order beginning with 0.
device specifies the device node to be used (for example, /dev/sda1).

Table 5-9. Pool Configuration File Keyword and Variable Descriptions

5.4.1. Examples

This example creates a 4-disk pool named pool0 that has a stripe size of 64K and an assigned minor number of 1:

poolname pool0
minor 1 subpools 1
subpool 0 128 4 gfs_data
pooldevice 0 0 /dev/sdb1
pooldevice 0 1 /dev/sdc1
pooldevice 0 2 /dev/sdd1
pooldevice 0 3 /dev/sde1

This example creates a 4-disk pool named pool1 that has a dynamic minor number composed of a striped subpool and a concatenated subpool:

poolname pool1
minor 0
subpools 2
# striped subpool
subpool 0 128 2 gfs_data
# concatenated subpool
subpool 1 0 2 gfs_data
pooldevice 0 0 /dev/sdb1
pooldevice 0 1 /dev/sdc1

pooldevice 1 0 /dev/sdd1
pooldevice 1 1 /dev/sde1