Re: RAID1 disk upgrade method

[Sean Greenslade <sean@seangreenslade.com>]

On Thu, Jan 28, 2016 at 01:24:07PM -0700, Chris Murphy wrote:
> >> 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?
> >>
> > That should safely disconnect the device, but you may still have to touch
> > some of the PM related stuff in the /sys/class/ directories for the disk
> > itself, and possibly do something to force it to flush the write cache
> > (toggling the write cache off then back on again usually does this).
> 
> Interesting, I figured a umount should include telling the drive to
> flush the write cache; but maybe not, if the drive or connection (i.e.
> USB enclosure) doesn't support FUA?
> 
> I wonder what the kernel sends to the device on restart/poweroff?

Yes, I did neglect to mention that. Wherever I said eject, I meant "send
1 to /sys delete, wait for drive to spin down, then remove." I also
unmount all partitions that are on that disk.

It's not an enclosure, it's hot-swap sata ports on the motherboard.

--Sean