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Options



Solid State Disk (SSD)
If you are installing Centrych to a solid state disk, selecting this option can help improve its performance and extend its longevity. Enabling this option also enables; zRAM, Zcache, tmpfs, noatime, and the swap and var partitions.

Please refer to the SSD page for detailed information on Centrych's SSD support.

Note: this option is unselected and disabled when the virtual machine system type is selected from the System panel.


Hibernation (suspend-to-disk)
Enabling this option enables the hibernate menu item in the desktop panel and also ensures that the swap partition will be large enough to save the state of memory to disk. This option will also enable the swap partition, which is required for hibernation to work.

Please be aware that the Ubuntu 12.04.2 release notes state that hibernation has been disabled by default due to it being "unreliable, very slow and confusing to have two suspend modes."

Note: this option is unselected and disabled when the virtual machine system type is selected from the System panel.

zRAM
This option is enabled by default and requires the swap partition to be enabled.

zRAM provides a ram-based, compressed filesystem that Centrych uses for high-priority swap space to improve overall system performance by minimizing swapping to a disk-based swap partition.

Please refer to the zRAM page for detailed information on Centrych's use of zRAM.

Note: this option defaults to unselected when the virtual machine system type is selected from the System panel.


Zcache
This option is enabled by default. When enabled, it causes the installer to add the boot option zcache=y to /etc/default/grub.

Zcache is a kernel facility that optimizes the use of the cleanpage cache. The page buffers in this cache contained data, typically from file I/O, that the kernel has released, so they are "clean" for reuse. Zcache will take these pages and attempt to compress them to save space.

Note: this option defaults to unselected when the virtual machine system type is selected from the System panel.


tmpfs
This option is enabled by default and requires the swap partition to be enabled. If disabled, the /tmp entry in /etc/fstab will be commented out.

tmpfs is a ram-based filesystem that is used in Centrych for the /tmp partition to improve system performance.

Please refer to the tmpfs page for detailed information on Centrych's use of tmpfs.

Note: this option defaults to unselected when the virtual machine system type is selected from the System panel.

Guided Partitioning Selections
Centrych provides an intelligent partition sizing algorithm that can optionally create partitions for the /var and /home directories.

Please refer to the disk partitioning page for detailed information regarding Centrych's partition sizing algorithm.


Mount Options
The noatime and nodiratime options, when enabled, can improve system performance by eliminating the extra disk I/O operations that are performed when updating file and/or directory last access times.

The noatime option disables last access time updates to files and directories while the nodiratime option only disables last access time updates to directories.

The noatime option also enables the /var directory, which will not have the noatime mount option added, since this option can interfere with some programs that read/write data to /var and require accurate last access times in order to operate correctly.
Note: the noatime option defaults to selected when the virtual machine system type is selected from the System panel, but the /var directory will not be selected.

Note: several web sites recommend adding both of these options to /etc/fstab, but this is not necessary. The Linux kernel source code, which has the final say in the matter, clearly shows that the noatime option is a superset of the nodiratime option.

Only one or the other, not both, are needed.


Note: the live DVD document for this page contains links to the following additional pages that have not been included here:
  • SSD
  • zRAM
  • tmpfs
  • Disk partitioning