Linux noatime impact on file access time

Linux noatime impact on file access time

Linux noatime impact on file access time

A file (such as abc) has three times:

# Stat abc

Access: 19:30:13. 665970572 + 0800
Modify: 19:28:53. 770002677 + 0800
Change: 19:28:53. 784001602 + 0800

Access is the last Access time of the file. The cat command will change this time. However, due to caching, only the first time you cat 'abc' in the short term

Will change this time. If this time is changed for each file access, the system with high performance requirements will be greatly affected. Therefore, you can set

When the object is accessed, the Access time is not changed.

Assume that the Mount directory/tmp is changed:

1) Access time changed for each Access: atime
$ Mount/tmp-o remount, atime

2) The Access time is not changed for each Access: noatime, nodiratime
$ Mount/tmp-o remount, noatime

In the case of 1, 2, you can test:

# Cp abc abc2 ### prevent cat caching, so cp creates a new file
# Stat abc2
# Cat abc2
# Stat abc2

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