Hi Andrew,
On 4/8/20 6:13 PM, Andrey ``Bass'' Shcheglov wrote:
Greetings,
[trim /]
Okay, so far, so good. I don't have any data, so a repair action can't
possibly harm it.
echo repair >>/sys/block/md4/md/sync_action
And the value of mismatch_cnt is still 384.
My first guess was that one of the hard drives was degrading, but
SMART attributes of both disks are ok (and nearly identical).
Can you please propose the explanation of the non-zero value?
And what else can I do to finally make it drop to zero (w/o
reassembling the whole array)?
This has always been a phenomenon possible with raid1, particularly when
swap is involved anywhere on top, but also where filesystems don't
exactly fill the raid device. Tail-packing inodes can leave strays, too.
My understanding is that it is an artifact of abandoned writes from
buffer cache, where the write to at least one mirror made it to the
device, but not to all mirrors. Logically harmless, except when scrubbing.
If it bothers you that much, fail one device, fill the entire device
with zeroes (dd with bs=512), then repartition, --add and wait for
rebuild complete. Then fail and do the same with the other. Use
--replace with a temporary third device if degraded is too risky.
Phil
