Sharing Logical Volumes via NFS on Redhat 8.0
(repost):
Regarding Sharing LVM LV's via NFS on Redhat 8.0...ie. mounting an LV from another machine while already having a LV on the same machine. Is it ok or not ok? I was talking to a buddy and he doesn't think it's a problem or an issue but...
the current documentation on Sistina's site states that sharing LV's is dangerous unless it's a SCSI or Fibre Storage Device?...and not only that ...adminisitration can only be done on one node? (is it really possible to create/resize lv's from one node/machine to another (that has an LV or was it meant to mean that it's only possible on cluster aware network storage devices)??? ....
http://tldp.org/HOWTO/LVM-HOWTO/x1232.html
under "Dangerous Operations - Sharing Logical LVM Volumes"
ie.
Quoted 7 lines
If you need to do any changes to the LVM metadata (regardless of >whether it affects volumes mounted on other nodes) you must go through >the following sequence. In the steps below ``admin node'' is any >arbirarily chosen node in the cluster. Admin node >Other nodes
---------- -----------
Close all Logical volumes (umount) vgchange -an
<make changes, eg lvextend>
vgscan
vgchange -ay
I'm thinking that it might not be a good idea to try to do maintenance on a LV that is mounted on another system...but i think it makes a whole heck of alot of sense to create/resize/mount an LV on a system before trying to mount it via an NFS share. :)
Any comments? I personally don't think it would be an issue either (to mount an LV on another box/system via an NFS mount) but i'd rather not take the chance of messing up any of the data on those LV's cuz their stuffed :)
Oh one other thing...if it has been proven that a Redhat 8.0 2.4-24?.x kernel can be patched to LVM 1.0.6+ ....will the data on those LV's be affected in any way or will it all be ok? :)
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Quoted 3 lines · DJ TweeQ
(repost):
Regarding Sharing LVM LV's via NFS on Redhat 8.0...ie. mounting an LV from another machine while already having a LV on the same machine. Is it ok or not ok? I was talking to a buddy and he doesn't think it's a problem or an issue but...
you are making a lot of confusion.
with nfs/samba you share a filesystem regardless of where it is located. (i consider 'share' to be a horrible term for exporting/mounting a remote filesystem)
yes you can do that.
Quoted 1 line
the current documentation on Sistina's site states that sharing LV's is dangerous unless it's a SCSI or Fibre Storage Device?...and not only that ...adminisitration can only be done on one node? (is it really possible to create/resize lv's from one node/machine to another (that has an LV or was it meant to mean that it's only possible on cluster aware network storage devices)??? ....
that part does not refer to nfs/samba it says that if you want to connect two different computers to the same hard disk .....
L.
Signature · 6 lines
Luca Berra -- [email protected] Communication Media & Services S.r.l. /"\ \ / ASCII RIBBON CAMPAIGN X AGAINST HTML MAIL / \
Hi,
Quoting DJ TweeQ <[email protected]>:
Quoted 4 lines
Regarding Sharing LVM LV's via NFS on Redhat 8.0...ie. mounting an LV from another machine while already having a LV on the same machine. Is it ok or not ok? I was talking to a buddy and he doesn't think it's a problem or an issue but...
Since there is no difference to the Samba server or the NFS server whether the underlying file system is managed via LVM or not, there should not be any problems regarding LVM.
Quoted 2 lines
the current documentation on Sistina's site states that sharing LV's is dangerous unless it's a SCSI or Fibre Storage Device?...and not only that
This advice is only valid if you use the same LV on two different nodes(=computers). If you use the LVM managed logival volumes on just one node at a time, you should not run into any problems.
Quoted 4 lines
I'm thinking that it might not be a good idea to try to do maintenance on a LV that is mounted on another system...but i think it makes a whole heck of alot of sense to create/resize/mount an LV on a system before trying to mount it via an NFS share. :)
It does make sense to not change the layout of the file system while the nfs server is running, but otherwise there is no problem between any user land application and LVM, since those applications are not aware that LVM is managing the logical volumes they are accessing.
Quoted 3 lines
Oh one other thing...if it has been proven that a Redhat 8.0 2.4-24?.x kernel can be patched to LVM 1.0.6+ ....will the data on those LV's be affected in any way or will it all be ok? :)
I'd go and see whether Redhat is providing Kernel packages containing LVM 1.0.6.
cu,
Sibbi
Signature · 4 lines
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