Installation guide

Statistical Information
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When dealing with file system size, the CacheFiles culling behavior is controlled by three settings in /
etc/cachefilesd.conf:
brun N%
If the amount of free space rises above N% of total disk capacity, cachefilesd disables culling.
bcull N%
If the amount of free space falls below N% of total disk capacity, cachefilesd starts culling.
bstop N%
If the amount of free space falls below N%, cachefilesd will no longer allocate disk space until
until culling raises the amount of free space above N%.
Some file systems have a limit on the number of files they can actually support (for example,
ext3 can only support up to 32,000 files). This makes it possible for CacheFiles to reach the file
system's maximum number of supported files without triggering bcull or bstop. To address this,
cachefilesd also tries to keep the number of files below a file system's limit. This behavior is
controlled by the following settings:
frun N%
If the number of files the file system can further accommodate falls below N% of its maximum file
limit, cachefilesd disables culling. For example, with frun 5%, cachefilesd will disable
culling on an ext3 file system if it can accommodate more than 1,600 files, or if the number of files
falls below 95% of its limit, i.e. 30,400 files.
fcull N%
If the number of files the file system can further accommodate rises above N% of its maximum
file limit, cachefilesd starts culling. For example, with fcull 5%, cachefilesd will start
culling on an ext3 file system if it can only accommodate 1,600 more files, or if the number of files
exceeds 95% of its limit, i.e. 30,400 files.
fstop N%
If the number of files the file system can further accommodate rises above N% of its maximum
file limit, cachefilesd will no longer allocate disk space until culling drops the number of files to
below N% of the limit. For example, with fstop 5%, cachefilesd will no longer accommodate
disk space until culling drops the number of files below 95% of its limit, i.e. 30,400 files.
The default value of N for each setting is as follows:
• brun/frun — 10%
• bcull/fcull — 7%
• bstop/fstop — 3%
When configuring these settings, the following must hold true:
0 <= bstop < bcull < brun < 100
0 <= fstop < fcull < frun < 100
11.5. Statistical Information
FS-Cache also keeps track of general statistical information. To view this information, use:
cat /proc/fs/fscache/stats