Live Boot Differences - Revision history

Rwh: /* How is /etc/systemd/journald.conf modified on a live boot? */

2015-09-24T14:05:16Z

How is /etc/systemd/journald.conf modified on a live boot?

← Older revision		Revision as of 10:05, 24 September 2015
Line 29:		Line 29:
	Starting with the NST 20 release, we decided to disable the logging of '''journalctl''' messages. This helps reduce the rate of RAM consumption during a ''live boot'' session.		Starting with the NST 20 release, we decided to disable the logging of '''journalctl''' messages. This helps reduce the rate of RAM consumption during a ''live boot'' session.

	To re-enable the logging of journal messages, change the ''Storage'' mode option from "'''none'''" back to "'''auto'''" in "''/etc/systemd/journald.conf''". For example:		To re-enable the logging of journal messages, change the ''Storage'' mode option from "'''none'''" back to "'''auto'''" in "'''/etc/systemd/journald.conf'''". For example:

	[Journal]		[Journal]

Rwh: /* How is /etc/systemd/journald.conf modified on a live boot? */

2015-09-24T14:04:56Z

How is /etc/systemd/journald.conf modified on a live boot?

← Older revision		Revision as of 10:04, 24 September 2015
Line 29:		Line 29:
	Starting with the NST 20 release, we decided to disable the logging of '''journalctl''' messages. This helps reduce the rate of RAM consumption during a ''live boot'' session.		Starting with the NST 20 release, we decided to disable the logging of '''journalctl''' messages. This helps reduce the rate of RAM consumption during a ''live boot'' session.

	To re-enable the logging of journal messages, change the ''Storage'' mode option from "'''none'''" back to "'''auto'''" in ''/etc/systemd/journald.conf''. For example:		To re-enable the logging of journal messages, change the ''Storage'' mode option from "'''none'''" back to "'''auto'''" in "''/etc/systemd/journald.conf''". For example:

	[Journal]		[Journal]

Rwh: /* How is /etc/systemd/journald.conf modified on a live boot? */

2015-09-24T14:04:08Z

How is /etc/systemd/journald.conf modified on a live boot?

← Older revision		Revision as of 10:04, 24 September 2015
Line 29:		Line 29:
	Starting with the NST 20 release, we decided to disable the logging of '''journalctl''' messages. This helps reduce the rate of RAM consumption during a ''live boot'' session.		Starting with the NST 20 release, we decided to disable the logging of '''journalctl''' messages. This helps reduce the rate of RAM consumption during a ''live boot'' session.

	To re-enable the logging of journal messages, change the ''Storage'' mode option from ''none'' back to ''auto'' in ''/etc/systemd/journald.conf''. For example:		To re-enable the logging of journal messages, change the ''Storage'' mode option from "'''none'''" back to "'''auto'''" in ''/etc/systemd/journald.conf''. For example:

	[Journal]		[Journal]

Paul Blankenbaker: Created page with "= General ''Live Boot'' Questions = There are significant differences between live booting a NST ISO versus booting a NST system after installing it to hard disk. This page disc..."

2014-02-19T12:47:34Z

Created page with "= General ''Live Boot'' Questions = There are significant differences between live booting a NST ISO versus booting a NST system after installing it to hard disk. This page disc..."

New page

= General ''Live Boot'' Questions =

There are significant differences between live booting a NST ISO versus booting a NST system after installing it to hard disk. This page discusses some of the differences.

== Why does a ''live boot'' continually to consume RAM? ==

When you perform a ''live boot'' from a read only ISO file system, the operating system installs a special ''overlay'' for the file system that keeps track of write operations. When you attempt to write to a file within the ISO file system, the ''overlay'' traps the operation and copies the write to memory instead. Each time one of these write operations occurs, RAM is allocated by the ''overlay'' system to hold the new contents of the file. This eats away at available memory and will eventually cause the system to crash.

Because of this, you should never expect a ''live boot'' to run for a extended period of time. A ''live boot'' may only run for minutes, hours or days (depending on the amount of file activity) before it crashes whereas a full hard disk installation should run indefinitely.

== Why isn't information saved between ''live boots''? ==

Since live boots are designed to run from read only file systems (like DVD media), there is no ability to automatically persist information between boots.

However, if you use the ''livecd-iso-to-disk'' tool to create a pseudo ''live boot'' USB memory stick, there are options which available which allow you to allocate space on the USB disk to be used as an overlay for the root file system for persisting information between sessions. This pseudo ''live boot'' is more similar to a ''live boot'' system than a full hard disk installation as the persistence layer will eventually fill over time and need to be cleared. Using the ''livecd-iso-to-disk'' tool, it is also possible to allocate a separate ''/home'' partition which will behave like a normally mounted partition.

== Why would I want to ''live boot''? ==

There are several reasons why you would want to ''live boot'' from a NST ISO image:

* To try out the NST distribution before committing to a hard disk installation.
* To install the NST distribution to a disk.
* To troubleshoot problems on a existing system.

= What are some configuration differences between a ''live boot'' and a hard disk installation? =

== How is ''/etc/systemd/journald.conf'' modified on a ''live boot''? ==

Starting with the NST 20 release, we decided to disable the logging of '''journalctl''' messages. This helps reduce the rate of RAM consumption during a ''live boot'' session.

To re-enable the logging of journal messages, change the ''Storage'' mode option from ''none'' back to ''auto'' in ''/etc/systemd/journald.conf''. For example:

[Journal]
Storage=auto
#Compress=yes
#Seal=yes
#SplitMode=login
#SyncIntervalSec=5m
#RateLimitInterval=30s
#RateLimitBurst=1000
#SystemMaxUse=
#SystemKeepFree=
#SystemMaxFileSize=
#RuntimeMaxUse=
#RuntimeKeepFree=
#RuntimeMaxFileSize=
#MaxRetentionSec=
#MaxFileSec=1month
#ForwardToSyslog=yes
#ForwardToKMsg=no
#ForwardToConsole=no
#TTYPath=/dev/console
#MaxLevelStore=debug
#MaxLevelSyslog=debug
#MaxLevelKMsg=notice
#MaxLevelConsole=info

After making the change, you will need to restart the ''systemd-journald.service'':

[root@taco-dev64 ~]# systemctl restart systemd-journald.service
[root@taco-dev64 ~]#