Installation guide

• User profiles and ttys information are stored in database files for
faster access and update (resulting in faster logins).
• The new utilities edauth and convuser are available.
See the Security manual and setrlimit
(2), edauth(8), and convuser(8).
G.10.1 ULTRIX Migration Issues
ULTRIX has had enhanced security since 1990; now DIGITAL UNIX has it.
Differences that affect migration are discussed in the Security manual, in
an appendix on migration.
G.11 File Systems
The following sections describe file system enhancements have been
implemented in DIGITAL UNIX Version 4.0B.
G.11.1 Advanced File System
The following sections describe Advanced File System (AdvFS)
enhancements have been implemented in DIGITAL UNIX Version 4.0B.
G.11.1.1 New Tuning Parameters for AdvFS
There is a new mechanism for limiting the amount of kernel memory that
AdvFS uses for its access structures. This may be necessary only for
systems with 64 MB or less memory, and AdvFS as the default file systems.
This is applicable to all hardware configurations.
There are two new kernel parameters relevant to AdvFS that you can
modify using the sysconfig or sysconfigdb commands. They are
AdvfsAccessMaxPercent and AdvfsAccessCleanupPercent.
G.11.1.2 AdvFS Now Supports Directory Truncation
Traditionally, AdvFS directories were never truncated, even though many
of the files in the directory had been deleted. This created a problem if the
directory file became very big. For example, if several hundred thousand
files were added to a directory, then the directory file itself grew very large.
Even though most of the files in that directory were subsequently deleted,
operations that required scanning the directory remained inefficient
because the entire directory file still needed to be read.
AdvFS now truncates directory files when all of the entries at the end of
the directory have been deleted. This truncation is done on 8 KB
boundaries, so the size of a directory is always a multiple of 8192.
Migration from ULTRIX Version 4.5 to DIGITAL UNIX Version 4.0B G–19