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fb0af3f2 | 1 | Where: /sys/fs/pstore/... (or /dev/pstore/...) |
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2 | Date: March 2011 |
3 | Kernel Version: 2.6.39 | |
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4 | Contact: tony.luck@intel.com |
5 | Description: 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 | ||
fb0af3f2 | 14 | # mount -t pstore -o kmsg_bytes=8000 - /sys/fs/pstore |
ca01d6dd | 15 | |
fb0af3f2 | 16 | $ ls -l /sys/fs/pstore/ |
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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 | ||
fb0af3f2 | 30 | $ rm /sys/fs/pstore/dmesg-erst-1 |
ca01d6dd | 31 | |
fb0af3f2 | 32 | The expectation is that all files in /sys/fs/pstore/ |
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33 | will be saved elsewhere and erased from persistent store |
34 | soon after boot to free up space ready for the next | |
35 | catastrophe. | |
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36 | |
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. | |
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42 | |
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 |