The next section of the configuration file presents a critical concept that it is important to understand

–the idea of the effects relationship. An effects relationship creates a relationship between two variables so that when one variable changes the other variable is re-evaluated – even if its final value is not based upon that variable.

In the next example, you can see that the value of _hp_pri_swap has been set to the size of the root disk and to the value of _hp_disk_layout (after that primary swap is initialized to a value more useful for swap).

This forces Ignite-UX to reevaluate the value of _hp_pri_swap whenever the size of the root disk changes (a smaller disk might force Ignite-UX to define a smaller swap space) or when the disk layout changes.

#

#The next two statements are used only to establish an effects

#relationship between the _hp_pri_swap variable and _hp_root_disk &

#_hp_disk_layout variables. The value is overwritten below.

#This makes the UI change the swap anytime either of these two

#values change.

init _hp_pri_swap = disk[_hp_root_disk].size init _hp_pri_swap = _hp_disk_layout

#default (recommended) swap size is 2 X memory

#Round up to the nearest 64MB so that we don't get a warning

#about it being adjusted in the UI. Really this just needs

#to be rounded to be a multiple of the physical-extent-size, but

#that can vary depending on the size of disk (4,8,16,32,64...)

#64MB should work on the majority of the disks available.

init _hp_pri_swap = (((MEMORY * 2) + 65535KB)/64MB)*64MB

Now you have other calculations for swap for different sized disks. The following example limits the size of swap for small disks. If you use init when setting both _hp_pri_swap and _hp_sec_swap, then the configuration only uses methods for setting the variables that allows the Ignite-UX GUI to modify them.

#Put an upper bounds of 1024Mb to the default swap size for disks

#less than 5Gb. And 4Gb swap for other disks

_hp_pri_swap > 1024Mb { disk[_hp_root_disk].size < 5120Mb {

init _hp_pri_swap = 1024Mb } else {

_hp_pri_swap > 4096Mb { init _hp_pri_swap = 4096Mb }

}

}

#Use a 128Mb as the default minimum amount of swap configured on any

#system. The real swap space will be reduced down to _hp_min_swap if

#there is not enough file system space.

(_hp_pri_swap < 128Mb)

{init _hp_pri_swap = 128Mb }

#Initialize the swap range minimum to what the default is _hp_min_swap = _hp_pri_swap

#If the system is limited on resources, then reduce the minimum so

#that the OS has a better chance of fitting. The swap size will

#still be set to the recommended value if there is enough disk space. (_hp_min_swap > 512Mb & disk[_hp_root_disk].size < 3000Mb)

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