vinum problems

[Александр Деревянко]

Chris Smith wrote:

>Hi,
>
>I've just built a machine with a vinum root successfully.  All vinum
>sets show that they are up and working.  There are two ATA disks in a
>RAID1 root formation.
>
>Some questions?
>
>1. The set has just failed completely (sorry it isn't up and working
>now) on the first reboot.  It is possible to bring the machine up from
>the primary disk with no problems but any attempt to start the mirror
>drive causes a panic with a "hardware error" although checking it with
>bsdlabel shows the partition table is intact.  Any ideas?  the drive is
>fine - i've pulled it and tested it and it's fine.  It's booting using
>BootMgr.
>
>I've killed it completely now by reloading the vinum config twice.  so
>it's out of action permanently. 
>
>I did make sure that there was enough space at the start of the disk for
>the vinum info to survive.
>
>2. Speed.  The vinum set is a "concat" disk.  The read performance was
>really slow (visibly so).  Can you boot off a striped volume and will it
>benefit me at all making it a striped volume at all rather than a
>concat?  
>
>hardware:
>
>SIL3112 SATA RAID controller.
>2x 80Gb Seagate barracuda ATA disks (ad4, ad6)
>FreeBSD-5.3-STABLE
>
>config:
>
>cant provide this - it won't boot any more.
>
>Any ideas?  Or any good resources on setting up a RAID1 root disk???
>
>Cheers,
>
>- Chris.
>
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>
>  
>

 From my point of view, vinum root partition is really useless. You will 
never have the availability comparable to hardware RAID (i mean, 
downtime), and will have a lot of troubles with booting from it.
 From my own expirience, the same results as root vinum partition can be 
made easily:
1. Make a small partition on every drive in the system. 128 Megs from 
every drive will be enought.
2. Make each partition bootable, and every day (by cron job in least 
activity hour) make a dump/restore from the main root partition to all 
other.
3. usr, var and all other partitions must reside on vinum partition, 
using rest of the space on the partition.
4. Swap partitions must also be made on every drive.

You can easily boot up from every disk in the system, and it will be 
always configured propertly (assuming you don't change a lot in root 
filesystem every day).

The described configuration is used at least one year on my work, for 
the SCM system server.

The only problem can be that you can't hot-unplug the disk from which 
you are booted.
But it's really very few system's build on average PC hardware and 
doesn't allowed to went of to the 5-10 minutes. In any case, the RAID 
(even hardware) is not enought to make a system with less than 1 
hour/year offline.

Best Regards,
Alexander Derevianko