On Thu, Jan 28, 2016 at 12:37 PM, Austin S. Hemmelgarn
[off-list ref] wrote:

On 2016-01-28 13:47, Sean Greenslade wrote:

quoted

On Thu, Jan 28, 2016 at 09:18:06AM -0700, Chris Murphy wrote:

quoted

Those read errors are a persistent counter. Use 'btrfs dev stat' to
see them for each device, and use -z to clear. I think this is in
DEV_ITEM, and it should be dev.uuid based, so the counter ought to be
with this specific device, not merely "sda1". So ... I'd look in the
journal for the time during the replace and see where those read
errors might have come from if this is supposed to be a new drive and
you're not expecting read errors already.

Like I mentioned in my first reply to this thread, sct erc... it's
very important to get these settings right.

I don't see anything that indicates read errors in my journal or dmesg,
though it's hard to tell given the rather scary-looking messages I get
whenever I eject a drive:

[Thu Jan 28 10:38:10 2016] ata6.00: exception Emask 0x10 SAct 0x8 SErr
0x280100 action 0x6 frozen
[Thu Jan 28 10:38:10 2016] ata6.00: irq_stat 0x08000000, interface fatal
error
[Thu Jan 28 10:38:10 2016] ata6: SError: { UnrecovData 10B8B BadCRC }
[Thu Jan 28 10:38:10 2016] ata6.00: failed command: READ FPDMA QUEUED
[Thu Jan 28 10:38:10 2016] ata6.00: cmd
60/00:18:00:79:02/05:00:00:00:00/40 tag 3 ncq 655360 in
                                     res
40/00:18:00:79:02/00:00:00:00:00/40 Emask 0x10 (ATA bus error)
[Thu Jan 28 10:38:10 2016] ata6.00: status: { DRDY }
[Thu Jan 28 10:38:10 2016] ata6: hard resetting link
[Thu Jan 28 10:38:10 2016] ata6: SATA link up 3.0 Gbps (SStatus 123
SControl 320)

If by eject you mean disconnect form the system, this is exactly the output
I would expect if you haven't done something to tell the kernel the disk is
disappearing.

How about something like:

# hdparm -Y /dev/sdb
# echo 1 /sys/block/sdb/device/delete

Then physically disconnect the drive, assuming hot-plug is supported
by all hardware?

-- 
Chris Murphy