RE: [Evms-devel] EVMS and Drive Linking

[Don M. <dlm...@us...>]

>EXT3 disk nr 2:
>I first set up ext3 with three disks. I powered down, rmoved the nr.2 disk
>and booted. Now my drive link (DL) was again reported broken and my nr.2
>disk was replaced with a placeholder like before. EVMS reported that it
was
>going to put my DL in read only mode, but I used Kevin's patch so this did
>not happen. I mounted the DL and was able to run fix, read/write data but
of
>course I got a lot of inode errors (missing as such), but it still worked.


>Then I tried to shrink the DL in EVMS but this was not possible. It's not
an
>option to shrink with the placeholder, you must shrink with a physical
disk
>with no errors. Also the replace is a no go. From what I see I can still
>extend the DL with another disk but I have not tried this.

When trying to shrink ... you right clicked on the DL object ... right?
It should have listed the shrink action.  Was the DL volume (/dev/evms/ld)
still mounted? Shrinking must be offline.  I would have unmounted the
volume and shrunk the volume down to just the 1st disk. Then I'd add
replacement disks and expand the volume.

>EXT3 disk nr 1:
>Now I got cocky so I shut down and installed the nr. 2 disk, booted, ran
>fsck.ext3 on it (just to make sure all was dandy), shut down again,
removed
>disk nr. 1. Well, now problems occurred. No longer could I mount the file
>system or run fsck.ext3 on it. I read in the man page to do a mke2fs -n
>/dev/evms/ld to find alternate superblocks, which I found, and then run
the
>command "fsck.ext3 -b "superblock number here" /dev/evms/ld". Sadly this
did
>not work, fsck only reported "Could this be a zero length partition?". I
>tried all the superblocks I found, but none worked.

Ok.

>Cannot find any other way to repair the remains of this partition. Maybe
if
>I could remove the placholder I could find some data for fsck to work
with.
>In my case here it needs to work trough 2,3 GB of empty/broken data blocks
>before finding any data. Maybe it only checks a little bit?

Dunno.

>ReiserFS disk nr 3 (should have been 2 but ...!):
>On reiserfs I could not mount the partition after the nr. 3 disk (last of
>three) was gone. Not even fsck.reiserfs could remedy this. Only the
"bread:
>Cannot read the block (1702001): (Input/output error)" was reported. Silly
>file system!

>ReiserFS disk nr 1:
>I did the same (remove nr. 1 disk) with reiserfs also and got similar
>results. Have tried the "fsck.reiserfs --rebuild-tree", "fsck.reiserfs
>--rebuild-sb" but all just reports (Input/output error). So I cannot get
It
>working again. Reiserfs just isn't there with error correction I think.

>Conclusion:
>Well my conclusion is that the data is saveable as long as we have the
first
>disk operative as long as you choose ext2/3 as the file system. Then we
can
>fix the FS to a working volume again, but we need to be able to remove or
>replace the placeholder. I would guess fsck would then just update the
inode
>table and not report i/o errors.

I am still wondering if you tried the shrink with /dev/evms/ld unmounted.
Seems to me like ext and reiser both allow shrinking.  If they could pack
data onto the first drive then you should have been able to recover either
fs by: shrinking the fs, replacing disks and expanding the fs.

>Now I am wondering whether to take the chance, or not. If I take the
chance
>then I need to set up AES-loop encryption. This will be cool to! :)

Thanks for trying things out!

-Don