X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?a=blobdiff_plain;f=man%2Fsystemd-readahead-replay.service.xml;h=b075f572dcd6eb44beddf8c5fdea88815387687f;hb=489124365d1d391864898b9869dd668eea5b2e28;hp=66d253454b78153e8965a7e7a5deff98d4a9f88b;hpb=f274ece0f76b5709408821e317e87aef76123db6;p=elogind.git
diff --git a/man/systemd-readahead-replay.service.xml b/man/systemd-readahead-replay.service.xml
index 66d253454..b075f572d 100644
--- a/man/systemd-readahead-replay.service.xml
+++ b/man/systemd-readahead-replay.service.xml
@@ -21,7 +21,7 @@
along with systemd; If not, see .
-->
-
+systemd-readahead-replay.service
@@ -56,7 +56,12 @@
systemd-readahead-collect.servicesystemd-readahead-done.servicesystemd-readahead-done.timer
- /usr/lib/systemd/systemd-readahead
+
+ /usr/lib/systemd/systemd-readahead/systemd-readahead
+ OPTIONS
+ COMMAND
+ DIRECTORY | FILE
+
@@ -67,7 +72,7 @@
time. systemd-readahead-replay.service
is a service that replays this access data collected
at the subsequent boot. Since disks tend to be
- magnitudes slower than RAM this is intended to improve
+ magnitudes slower than RAM, this is intended to improve
boot speeds by pre-loading early at boot all data on
disk that is known to be read for the complete boot
process.
@@ -75,9 +80,9 @@
systemd-readahead-done.service
is executed a short while after boot completed and signals
systemd-readahead-collect.service
- to end data collection. On this signal this service
+ to end data collection. On this signal, this service
will then sort the collected disk accesses and store
- information about them disk in
+ information about them in
/.readahead.Normally, both
@@ -87,22 +92,118 @@
are activated at boot so that access patterns from the
preceding boot are replayed and new data collected
for the subsequent boot. However, on read-only media
- where the collected data cannot be stored it might
+ where the collected data cannot be stored, it might
be a good idea to disable
systemd-readahead-collect.service.On rotating media, when replaying disk accesses
- at early boot
+ at early boot,
systemd-readahead-replay.service
will order read requests by their location on disk. On
non-rotating media, they will be ordered by their
original access timestamp. If the file system supports
- it
+ it,
systemd-readahead-collect.service
will also defragment and rearrange files on disk to
optimize subsequent boot times.
+
+ Options
+
+ systemd-readahead understands
+ the following options:
+
+
+
+
+
+
+ Prints a short help text
+ and exits.
+
+
+
+
+
+ Prints a short version
+ string and exits.
+
+
+
+
+
+ Maximum number of
+ files to read ahead. Only valid
+ for thes collect
+ command.
+
+
+
+
+
+ Maximum size of files
+ in bytes to read ahead. Only valid
+ for the collect
+ and replay
+ commands.
+
+
+
+
+
+ Maximum time in microseconds
+ to spend collecting data. Only valid
+ for the collect
+ command.
+
+
+
+
+
+
+ Commands
+
+ The following commands are understood by
+ systemd-readahead:
+
+ collect
+ [DIRECTORY]
+
+ Collect read-ahead data on
+ early boot. When terminating, it will
+ write out a pack file to the indicated
+ directory containing the read-ahead
+ data.
+
+
+
+
+ replay
+ [DIRECTORY]
+
+ Perform read-ahead on the
+ specified directory tree.
+
+
+
+
+ analyze
+ [FILE]
+
+ Dumps the content of the
+ read-ahead pack file to the
+ terminal. For each file, the
+ output lists approximately how
+ much will be read ahead by
+ the replay
+ command.
+
+
+
+
+
+
See Also