vinum - suitablity for use with removable disks
tfrank at optushome.com.au
Thu Feb 19 20:13:12 PST 2004
On Fri, Feb 20, 2004 at 09:46:48AM +1100, Pietralla, Siegfried P wrote:
> i want to use vinum with some removable ( e.g. usb2 ) hard disks. i want to
> use vinum because : it lets me create as many appropriately sized volumes as
> i need ; and, it doesn't matter whether the disk connects as da0 or da1
> since vinum uses it's own label.
> my question is, will vinum comfortably handle more than one disk where there
> is an equal chance that none, one or more will be online at any one time. if
> i plug in a disk, will i need to "restart" or "bring up" or whatever the
> disk, or the plex etc every time a disk comes back online? if so, what is
> the smallest set of commands i can use to do this?
> note that i only intend to run single plexes ( no mirrors or raid 5 ) where
> all subdisks reside on the same physical disk.
> any thoughts or experiences appreciated.
Note I have not tried this myself - will have to get USB support running to
try it locally.
Basic setup is quite straightforward (as per any other disk):
1. fdisk the USB drive to put a freebsd slice on there
2. create vinum partition on the disk
3. create vinum drive with the device
4. build subdisks/plex/volumes etc
5. newfs volumes
6. mount volume
7. transfer data as needed
I expect you would want to at least umount the volume before
removing a device.
Probably want to 'stop' the volume/plex/subdisk also.
That way vinum says disk is 'down' and wont try to write to it.
You should then be able to remove safely (minus any other
FreeBSD USB disk caveats that I am not aware of)
Possibly camcontrol stop would be appropriate - I'll have to
do some research on this.
If the disk is used in a different USB port etc such that it
gets a different device name I expect Vinum should still be
able to recognise it.
My experience here is nonexistant.
At such time you should be able to start the objects and
mount the filesystem again.
If nothing else this has raised some ideas for things to spend a day
or two on :)
Hope there was something useful in that,
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