Historically this was usually due to some distributions
having buggy init scripts and/or installers that didn't
correctly detect this case and take appropriate
-countermeasures. However, it's still possible, despite the
-best efforts of init script and installer authors to not be
-able to detect this misconfiguration, usually due to a
+countermeasures. Unfortunately, this is occasionally
+true even today, usually due to a
buggy or misconfigured virtualization manager or the
installer not having access to a network time server
during the installation process. So by default, we allow
(i.e., connected to a serial port) and so a large amount of output could
end up delaying the boot process for a long time (potentially hours).
.TP
+.I readahead_mem_pct
+Use this percentage of memory to try to read in metadata blocks ahead of the
+main e2fsck thread. This should reduce run times, depending on the speed of
+the underlying storage and the amount of free memory. There is no default, but
+see
+.B readahead_mem_pct
+for more details.
+.TP
+.I readahead_kb
+Use this amount of memory to read in metadata blocks ahead of the main checking
+thread. Setting this value to zero disables readahead entirely. By default,
+this is set the size of two block groups' inode tables (typically 4MiB on a
+regular ext4 filesystem); if this amount is more than 1/50th of total physical
+memory, readahead is disabled.
+.TP
.I report_features
If this boolean relation is true, e2fsck will print the file system
features as part of its verbose reporting (i.e., if the