Jakob Østergaard wrote:
> On Tue, Nov 02, 1999 at 02:16:57PM -0600, Mark Ferrell wrote:
> > You also have to remember that in most LVM implementations adding a device to the
> > LVM does not add it to the raid.
> [snip]
> > "Oh look .. the 90G raid5 array is getting pretty full .. I guess we should add
> > more drives to it .. oh .. hold it .. it's a raid5 .. we can't just add more space
> > to it .. we have to LVM attach another raid5 array to the array in order to keep
> > redundancy"
>
> My only experience with LVM is from HPUX. I could create the equivalent of RAID-0
> there using LVM only, and it is my understanding that LVM for Linux can do the same.
> It should indeed be possible to create the equivalent of RAID-5 as well, using only
> LVM. But still the LVM would have to support extending the parity-VG.
LVM on AIX and HPUX is functionally the same, only in AIX you don't have to buy the
extra SW package to resize the FS while it's mounted. Actually .. they may be derrived
from the same base code .. but I am not certain there.
> raidreconf will hopefully be useful for people to do these tricks, until the LVM
> gets the needed features (which may be years ahead).
Yah .. AIX supports a method of doing stripping and parity .. but as I understand the
LVM
support is tightly bound to the JFS in order to make this possible. As well, I believe
AIX
no longer supports reducing the size of FS. Actually .. I am not certain it was ever a
'supported' feature .. though I have tools for doing it on AIX3.
> > The ability to add/remove/resize the lower level raid enviroment would be in my
> > opinion alot more beneficial in the long run if it is possible.
>
> IMHO the support for redundancy should be in the LVM layer. This would eliminate
> the need for RAID support as we know it today, because LVM could provide the same
> functionality, only even more flexible. But it will take time.
A single layer approach would deffinately reduce alot of complications.
>
> Today, and the day after, we're still going to use the RAID as we know it now. LVM
> is inherently cooler, but that doesn't do everyone much good right now as it doesn't
> provide the equivalent of a resizable RAID-5. It's my belief that people need that.
Very much agreed.
> Cheers,
> --
> ................................................................
> : [EMAIL PROTECTED] : And I see the elder races, :
> :.........................: putrid forms of man :
> : Jakob Østergaard : See him rise and claim the earth, :
> : OZ9ABN : his downfall is at hand. :
> :.........................:............{Konkhra}...............:
--
Mark Ferrell
