[mythtv-users] RAID on Fedora Core 3?

[Max Waterman]

So, how did *you* stop /dev/md1 disappearing?

...or is it just that you created your devices in fc2 and/or during the
install process that makes the difference?

Max.

Blues Guy wrote:
> Max Waterman wrote:
> 
>> I'm having a problem creating my raid device.
>>
>> My first raid device is /dev/md0 and that works fine; but /dev/md1 
>> doesn't exist.
>>
>> I can create it manually with :
>>
>> # mknod /dev/md1 b 9 1
>> # mknod /dev/md2 b 9 2
>> # mknod /dev/md3 b 9 3
>> ... etc
>>
>> and reassemble and mount again, and all is well...but the /dev/mdX 
>> files (apart from /dev/md0)
>> disappear when I reboot.
>>
>> How do I stop them disappearing?
>>
>> Max.
>>
> Jumping into this conversation late, but better later than never maybe?  
> I use an old 850Mhz PIII on an old IntelBX motheboard with a new(ish) 
> Promise SATA150 TX4 (non-raid, i.e. cheap) card, and do software raid 
> across four 250GB Seagate SATA (Dmesg says "Model: HDS722525VLSA80") 
> with three PVR-250 encoders.  This box also acts as the NFS store for my 
> mythvideo collection and my diskless frontend.  It holds up reasonably 
> well, although it's slightly underpowered when it's doing a lot of 
> commercial flagging.
> 
> I wanted to use all four disks as RAID5, but you can't boot from RAID5, 
> and I also wanted LVM to be able to stretch the filesystem down the 
> road...so my raid config ended up looking like this.. (as setup during 
> FC2 install)
> 
> [root at atlas log]# df -h
> Filesystem            Size  Used Avail Use% Mounted on
> /dev/mapper/Volume00-LogVol01
>                      9.7G  3.0G  6.3G  32% /
> /dev/mapper/Volume00-LogVol02
>                      150G   78G   73G  52% /mnt/exports
> /dev/mapper/Volume00-LogVol03
>                      537G  377G  160G  71% /mnt/store
> /dev/md0               99M  9.8M   84M  11% /boot
> 
> The three logical volumes sit on top of  /dev/md1 and boot is obviously 
> /dev/md0.
> 
> mdadm reports:
> 
> [root at atlas log]# mdadm -D /dev/md0
> /dev/md0:
>        Version : 00.90.01
>  Creation Time : Wed Oct 20 00:50:16 2004
>     Raid Level : raid1
>     Array Size : 104192 (101.75 MiB 106.69 MB)
>    Device Size : 104192 (101.75 MiB 106.69 MB)
>   Raid Devices : 2
>  Total Devices : 4
> Preferred Minor : 0
>    Persistence : Superblock is persistent
> 
>    Update Time : Sun Jan  2 12:23:55 2005
>          State : clean, no-errors
> Active Devices : 2
> Working Devices : 4
> Failed Devices : 0
>  Spare Devices : 2
> 
> 
>    Number   Major   Minor   RaidDevice State
>       0       8        1        0      active sync   /dev/sda1
>       1       8       17        1      active sync   /dev/sdb1
>       2       8       49       -1      spare   /dev/sdd1
>       3       8       33       -1      spare   /dev/sdc1
>           UUID : 2c8b5b5d:2a357a87:6f39ff28:fea0972d
>         Events : 0.791
> 
> [root at atlas log]# mdadm -D /dev/md1
> /dev/md1:
>        Version : 00.90.01
>  Creation Time : Wed Oct 20 00:43:38 2004
>     Raid Level : raid5
>     Array Size : 732274176 (698.35 GiB 749.85 GB)
>    Device Size : 244091392 (232.78 GiB 249.95 GB)
>   Raid Devices : 4
>  Total Devices : 4
> Preferred Minor : 1
>    Persistence : Superblock is persistent
> 
>    Update Time : Sun Jan  2 06:13:14 2005
>          State : dirty, no-errors
> Active Devices : 4
> Working Devices : 4
> Failed Devices : 0
>  Spare Devices : 0
> 
>         Layout : left-asymmetric
>     Chunk Size : 256K
> 
> Rebuild Status : 82% complete
> 
>    Number   Major   Minor   RaidDevice State
>       0       8        2        0      active sync   /dev/sda2
>       1       8       18        1      active sync   /dev/sdb2
>       2       8       34        2      active sync   /dev/sdc2
>       3       8       50        3      active sync   /dev/sdd2
>           UUID : 5ffc83ea:ead70b39:511cd279:86fd2eeb
>         Events : 0.7539628
> 
> So you see /dev/md0 actually has two somewhat wasted hot-spares, but it 
> keeps all the partition sizes in sync and makes it easier for me to 
> manage.  Besides it's only a 100MB per drive which, in myth terms, is puny.
> 
> You can also see that my machine crashed earlier and the array is still 
> resyncing. :-)  I blame the New Year's Twilight Zone marathon I 
> recorded... it had been running fine for the last two months.
> 
> Don't know if this is useful, but there's my 2 cents...
> 
> Greg
> 
>