[ENBD] NBD with RAID-1 ?

[Leonid Andreev]

On 30 Oct 2000, Administrator wrote:

> Hello,
> 
> Did anybody used NBD into RAID level 1 configuration ?

I'm using ENBD 2.4.14 with RAID1 (raidtools 0.90) under linux kernel
2.2.16-3smp. This is my /etc/raidtab: 

raiddev /dev/md0
    raid-level 			1
    nr-raid-disks 		2
    nr-spare-disks 		0
    persistent-superblock 	1
    chunk-size 			4
 
    device 			/dev/sdb1
    raid-disk 			0
    device 			/dev/nda
    raid-disk 			1

/dev/sdb1 is a local scsi disk, /dev/nda is an nbd block devie served by a
remote server; the partition on the remote server is physically identical
to the local /dev/sdb1. Once you have /dev/nda up and running, you can
start the RAID device above by

raidstart /dev/md0

check out /proc/mdstat to see if the raid is happy. You want to see
something like

md0 : active raid1 [dev 2b:00][1] sdb1[0] 8891840 blocks [2/2] [UU]

the "[2/2] [UU]" part is important: -- it indicates that the raid
is seeing both mirrors. If this is the case, you can start /dev/md0 as if
it were a normal block device. 

mke2fs /dev/md0
mount /mnt/diskN /dev/md0

etc. etc.


good luck, 

-Leonid.