Linux RAID mdadm: what does 'Events' mean?
It's actually 2 integers.
printf("\n Events : %d.%d\n\n", sb->events_hi, sb->events_lo);
events_hi and events_lo are counters of the update events their sum is the total md events, the hi and lo (I ASSUME, without looking further into the code) represent the "significance" of the update.
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Jaydee
After scraping through an engineering degree I spent a lot of my time working for accountants. I'm currently working for a Helicopter Charter Company where mobile web solutions are really useful. Most of my current expertise is with Delphi 7 / MySQL / Java / Tomcat with bits of PHP and all kinds of odds and sods.
Updated on September 18, 2022Comments
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Jaydee over 1 year
When I type
mdadm --detail /dev/md0
I get a lots of useful information most of which I understand. However I also get a line that reads:
Events : 0.710
Where the number varies.
Naively, I thought an event either happened or it didn't. How can I have only 0.710 of an event? Or if you prefer why is "Events" not an integer value?
EDIT
After seeing user's answer below, I dug into the code a bit and found
`#if __BYTE_ORDER == __BIG_ENDIAN
144 __u32 events_hi; /* 7 high-order of superblock update count */
145 __u32 events_lo; /* 8 low-order of superblock update count */
...
148 #else
149 __u32 events_lo; /* 7 low-order of superblock update count */
150 __u32 events_hi; /* 8 high-order of superblock update count */
...
153 #endif`
So "Events" is high-order and low order of "superblock update count" https://raid.wiki.kernel.org/index.php/Superblock
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Jaydee almost 11 yearsAh ha! So the .710 is 710 (presumably) low priority events. Many thanks for digging this out. I wonder if there is a list of "events_lo" type events (and indead events_hi) anywhere.