Luca,
Here are the results the modifications you suggested :
# : mdadm -D /dev/md/0
/dev/md/0:
Version : 00.90.00
Creation Time : Tue Apr 23 15:55:33 2002
Raid Level : multipath
Array Size : 17688448 (16.86 GiB 18.11 GB)
Raid Devices : 1
Total Devices : 2
Preferred Minor : 0
Persistence : Superblock is persistent
Update Time : Tue Apr 23 16:00:31 2002
State : dirty, no-errors
Active Devices : 1
Working Devices : 2
Failed Devices : 0
Spare Devices : 1
Number Major Minor RaidDevice State
0 8 1 0 active sync
/dev/scsi/host2/bus0/target0/lun0/part1
1 65 97 1 active
/dev/scsi/host3/bus0/target0/lun0/part1
UUID : b0191dc2:e89b155f:66c3e4e4:fa925d37
# : cat /proc/mdstat
md0 : active multipath scsi/host3/bus0/target0/lun0/part1[1]
scsi/host2/bus0/target0/lun0/part1[0]
17688448 blocks [1/2] [U]
Again only one HBA is utilized, which is verified via the previous testing I
had run. I believe that even after we hack the code to set all disks to
'active', the raid code will still only use the first drive it finds that is
not a spare.
--Snippit-- (multipath.c)
* Mark all disks as spare to start with, then pick our
* active disk. If we have a disk that is marked active
* in the sb, then use it, else use the first rdev.
--Snippit--
Additionally I have noticed the following in my syslog on the mkraid of the
multipath device.
--Snippit--
[events: 00000002]
[events: 00000002]
md: autorun ...
md: considering scsi/host3/bus0/target0/lun0/part1 ...
md: adding scsi/host3/bus0/target0/lun0/part1 ...
md: adding scsi/host2/bus0/target0/lun0/part1 ...
md: created md0
md: bind<scsi/host2/bus0/target0/lun0/part1,1>
md: bind<scsi/host3/bus0/target0/lun0/part1,2>
md: running:
<scsi/host3/bus0/target0/lun0/part1><scsi/host2/bus0/target0/lun0/part1>
md: scsi/host3/bus0/target0/lun0/part1's event counter: 00000002
md: scsi/host2/bus0/target0/lun0/part1's event counter: 00000002
md0: max total readahead window set to 124k
md0: 1 data-disks, max readahead per data-disk: 124k
multipath: making IO path scsi/host3/bus0/target0/lun0/part1 a spare path
(not in sync)
multipath: device scsi/host3/bus0/target0/lun0/part1 operational as IO path 1
multipath: device scsi/host2/bus0/target0/lun0/part1 operational as IO path 0
(checking disk 0)
(checking disk 1)
multipath: array md0 active with 1 out of 1 IO paths (1 spare IO paths)
md: updating md0 RAID superblock on device
md: (skipping alias scsi/host3/bus0/target0/lun0/part1 )
md: scsi/host2/bus0/target0/lun0/part1 [events: 00000003]<6>(write)
scsi/host2/bus0/target0/lun0/part1's sb offset: 17688448
--Snippit--
Please note the comment about host3 being marked a spare path (not in sync).
Any comments as always, are welcome.
On April 19, 2002 05:58 pm, Luca Berra wrote:
> Oops,
> seems i forgot about spares :(
>
> multipath.c sets all disks as spares to start with.
> a dirty hack could be:
>
> look for:
> /*
> * Mark all disks as spare to start with, then pick our
> * active disk. If we have a disk that is marked active
> * in the sb, then use it, else use the first rdev.
> */
>
> below you will find:
> if (disk_active(desc)) {
> if(!conf->working_disks) { //remove this line
> printk(OPERATIONAL, partition_name(rdev->dev),
> desc->raid_disk);
> disk->operational = 1;
> disk->spare = 0;
> conf->working_disks++;
> def_rdev = rdev;
> } else { //remove this line
> mark_disk_spare(desc); //remove this line
> } //remove this line
> } else
> mark_disk_spare(desc);
>
> remove the lines i market with //remove this line
> and it should activate the disks
>
> i wont have a system at hand to test this, so please let me know
> if it works
>
> we then need to clean up the logic for initialization
> since is nonsense to set a disk as spare then reset it back
> again as operational, but this could work for a start
>
> good luck
>
> L.
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