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Tony Luckca01d6d2010-12-28 14:25:21 -08001Where: /dev/pstore/...
Luck, Tony366f7e72011-03-18 15:33:43 -07002Date: March 2011
3Kernel Version: 2.6.39
Tony Luckca01d6d2010-12-28 14:25:21 -08004Contact: tony.luck@intel.com
5Description: Generic interface to platform dependent persistent storage.
6
7 Platforms that provide a mechanism to preserve some data
8 across system reboots can register with this driver to
9 provide a generic interface to show records captured in
10 the dying moments. In the case of a panic the last part
11 of the console log is captured, but other interesting
12 data can also be saved.
13
Luck, Tony366f7e72011-03-18 15:33:43 -070014 # mount -t pstore -o kmsg_bytes=8000 - /dev/pstore
Tony Luckca01d6d2010-12-28 14:25:21 -080015
16 $ ls -l /dev/pstore
17 total 0
18 -r--r--r-- 1 root root 7896 Nov 30 15:38 dmesg-erst-1
19
20 Different users of this interface will result in different
21 filename prefixes. Currently two are defined:
22
23 "dmesg" - saved console log
24 "mce" - architecture dependent data from fatal h/w error
25
26 Once the information in a file has been read, removing
27 the file will signal to the underlying persistent storage
28 device that it can reclaim the space for later re-use.
29
30 $ rm /dev/pstore/dmesg-erst-1
31
32 The expectation is that all files in /dev/pstore
33 will be saved elsewhere and erased from persistent store
34 soon after boot to free up space ready for the next
35 catastrophe.
Luck, Tony366f7e72011-03-18 15:33:43 -070036
37 The 'kmsg_bytes' mount option changes the target amount of
38 data saved on each oops/panic. Pstore saves (possibly
39 multiple) files based on the record size of the underlying
40 persistent storage until at least this amount is reached.
41 Default is 10 Kbytes.
Matthew Garrettdee28e72011-07-21 16:57:55 -040042
43 Pstore only supports one backend at a time. If multiple
44 backends are available, the preferred backend may be
45 set by passing the pstore.backend= argument to the kernel at
46 boot time.
47