Sun Microsystems 10 Comparison between sparse-root zones and whole-root zones, Whole-root Var Usr

Version 3.1-enSolaris 10 Container Guide - 3.1 4. Best Practices Effective: 30/11/2009

4.1.3. Comparison between sparse-root zones and whole-root zones

[dd]From the considerations listed above, a comparison can be drawn between sparse-root zones and whole-root zones. In the vast majority of cases, sparse-root zones are used.

	Sparse root zone	Whole root zone
Disk space required	70 - 100 MB	2600 - 3600 MB
Quick creation of zones	+	-
Quick patching of zones	+	-
Central software installation and maintenance	+	+
Efficient use of main memory	+	-
Independent installation, modification and patching of parts of the	-	+
operating system within the zone
Write option in system directories	-	+

Table 3: [dd] Comparison between sparse-root zones and whole-root zones

Global Zone		Sparse-root
/		/
/var		/var
/usr	--> lofs	inherit-pkg-dir
/lib	--> lofs	inherit-pkg-dir
/sbin	--> lofs	inherit-pkg-dir
/platform	--> lofs	inherit-pkg-dir
~ 3.6 GB
		~100 MB

Figure 23: [dd] Schematic comparison between sparse-root zones and whole-root zones

Whole-root

/

/var

/usr

/

lib /sbin

/platform

~3.6 GB

4.1.4. Software in zones

[dd]For users and operators, the question arises whether their software runs in a local zone and also whether it is certified for that purpose by the software manufacturer. Applications can be qualified according to http://developers.sun.com/solaris/articles/zone_app_qualif.html for use in local zones.

As a general rule, applications that get by with normal user privileges also run in a local zone.

Software that requires special privileges or must run under root privileges should be considered separately. Direct access to devices, device drivers, separate kernel modules, ISM or direct access to the network and network modules are considered to be particularly critical. Details on this can be read at http://developers.sun.com/solaris/articles/application_in_zone.html under "Bringing your Application into the Zone".

If the software is able to run in a local zone, the installation and configuration mechanism of the application must furthermore be considered. Thus, care must be taken that during the installation in local zones no write operations are required in inherit-pkg-dir, e.g. for an installation in /usr or /usr/local, if /usr is an inherit-pkg-dirfor a sparse root zone.

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