On Thu, 2002-10-31 at 20:47, Andreas Dilger wrote:
> > OK -- so using lvextend I can extend it. But once it's extended, I can
> > no longer mount it. I get:
> >
> > mount: wrong fs type, bad option, bad superblock on
> > /dev/data1/.mer_dev.hourly.3, or too many mounted file systems
> >
> > Is there something I'm missing here? (ok -- obviously yes...)
>
> You must have gotten some sort of error in the syslog after this
> (dmesg will show you).
EXT2-fs: lvm(58,5): couldn't mount because of unsupported optional
features (4).
I'm running RedHat 7.3 with 2.4.18-10smp and the RedHat lvm-1.0.3-4 RPM
package. Tried mounting both with no options, with -t ext2, and with -t
ext3. Same results in all cases. Doing the mount in verbose mode doesn't
give any extra info.
...I'd like to figure this out, but in truth there's a more serious
problem with snapshots that means I can't use it. When the file-system
is under load, having a snapshot increases the system load by many
multiples. Example:
- 250 GB filesystem, copying data to it at a rate of aobut 56 Mbs
- Load is constantly less than .2, usually down around .05
- Create one snapshot on the volume: load is now over 1 continuously.
- Create a 2nd snapshot: system load now jumps over 4.5 continuously.
- Same experiment with the filesystem used sparsely sees no
significant system load increase... so it has to do with
usage.
I'd have expected performance loss by creating the snapshots, but I
expect it to be a linear loss (ie: 2 snapshots is twice the load of 1
snapshot).
Is this sort of performance loss a known issue? I've got another way of
doing pseudo-snapshots without LVM, but it'd be really nice to use the
built-in snapshotting for a number of reasons. I can't find any mention
of this sort of thing anywhere, and don't see it addressed in any of the
changelogs.
This is on the above RedHat system, which is a dual-processor Athlon
1800 system with 1GB of memory that's doing nothing except holding
volumes and NFS serving them out. VGs are on two 3-ware ide-RAID RAID 5
setups of 960 GB apiece.
--
------------------------------------------------------
Jim King
Multimission Image Processing Lab (MIPL) Engineering Group
Science Data Processing Systems Section, Jet Propulsion Lab
James.King@jpl.nasa.gov
------------------------------------------------------
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