[dm-devel] dmsetup status not clear

[Konrad Rzeszutek]

> Why is the new disk showing up as `sdc' instead of `sdb'  and why is

I can't comment on the naming - but in regards to the write cache - that is
the information the kernel gets from the device using SCSI commands (to be
exact it MODE_SENSE). The device has it disabled. You can fiddle with MODE_SELECT
command if you want to enable it - but keep in mind that when you have a RAID
it is advised to turn cache off. Unless your computer has a UPS connected so that 
you can flush the data immediately and turn off caching.

> the write cache disabled?
> 
> 
> Of course similar two lines below showing up only in dmesg and not in
> messages file
> 
> 
> [ 2465.456628] ata4: exception Emask 0x10 SAct 0x0 SErr 0x150000
> action 0xe frozen
> [ 2465.543901] ata4: SError: { PHYRdyChg CommWake Dispar }
> [ 2465.606247] ata4: hard resetting link
> 
That is OK.
> 
> Also, how can I find out if/when the raid1 sync completed? I do not
> follow what the dmsetup status is saying

cat /proc/dmstatus should give you some details.

> 
> 
> ~$ sudo dmsetup status
> nvidia_eeffhbef5: 0 6458067 linear
> nvidia_eeffhbef1: 0 149838192 linear
> nvidia_eeffhbef: 0 156301486 mirror 2 8:0 8:16 1183/1193 1 AD 1 core

That is just the static mapping it has setup. Where it says that disks 8:0 and 8:16
are part of the of your RAID. Do a 'ls /dev/ | grep 8' and you will see what 
the 8:0, and 8:16 correspond to.

> 
> 
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