On Sat, 10 Aug 2013 07:19:27 PM Russell Coker wrote: > But what does generation_errs mean? I'm seeing some on one system. > Should I be concerned? If I write a Nagios check which ones should be > warnings and which ones errors?
All I know is that ioctl.h says:
BTRFS_DEV_STAT_GENERATION_ERRS, /* an indication that blocks have not
* been written */
Looking at the kernel code that only seems to get incremented during a scrub.
The code that does that says:
} else if (generation != le64_to_cpu(h->generation)) {
sblock->header_error = 1;
sblock->generation_error = 1;
}
The generation there is from the btrfs inode structure, the header says:
/* full 64 bit generation number, struct vfs_inode doesn't have a big
* enough field for this.
*/
u64 generation;
The wiki says:
https://btrfs.wiki.kernel.org/index.php/Glossary
# generation
# An internal counter which updates for each transaction. When a
# metadata block is written (using copy on write), current generation
# is stored in the block, so that blocks which are too new (and hence
# possibly inconsistent) can be identified.
and:
https://btrfs.wiki.kernel.org/index.php/Btrfs_design
# Everything that points to a btree block also stores the generation
# field it expects that block to have. This allows Btrfs to detect
# phantom or misplaced writes on the media.
HTH!
> Also why does it give the following errors about trying to open /dev/sr0
> when using a BTRFS RAID-1 filesystem? Below is for a RAID-1 over /dev/sdb
> and /dev/sdc.
I don't get that here, I'm building btrfs-progs from git at commit
194aa4a1bd6447bb545286d0bcb0b0be8204d79f (July 5th), aka:
btrfs-progs$ git describe --tags
v0.20-rc1-358-g194aa4a
cheers!
Chris
--
Chris Samuel : http://www.csamuel.org/ : Melbourne, VIC
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