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Re: [linux-lvm] pvmove root filesystem?



Is redhat 7.1 using ext3 already automatically? How does one upgrade from
ext2 to ext3?
At 11:50 PM 11/1/01 -0700, you wrote:
>On Nov 02, 2001  00:33 -0500, Brian J. Murrell wrote:
>> > Brian, the "pvmove" mechanism is not yet 100% safe for mounted
filesystems.
>> 
>> Ugh.  I was hoping to not hear something like this.  Has it gotten any
>> better recently?  What I mean is my LVM identifies itself as:
>> 
>> LVM version LVM 0.9.1_beta7(ish)  by Heinz Mauelshagen  (20 June 2001)
>> lvm -- Module successfully initialized
>
>Well, there have been a lot of changes to the pvmove locking code and
>such since then.  Whether it actually makes a difference is hard to
>tell.
>
>> Am I going to run into even more problems with this verion of LVM vs.
>> the latest or has the "live" pvmove stuff not changed much between the
>> version I am running and current.
>
>Nobody has really done any good testing on it.
>
>> > There may be a problem with the ext3 journal, it is
>> > hard to say (there was a report on the ext3 mailing list, but I never got
>> > enough details to sort it out.
>> 
>> Hrm.  I am running ext3 on my filesystems as well.
>
>That's why I mentioned it.  You could read the thread in the ext3-users
>archive at RedHat.
>
>> I just don't want this to turn into a "restore my system from tape"
>> type of operation, especially if the system is operating (i.e.
>> processing mail, etc.) while it all goes down the sh*tter.  Maybe I
>> will contemplate it based on your thoughts of how much worse the
>> operation could be based on my version of LVM installed.
>
>Well, if you are worried about mail, turn it off, back up your mail
>spool, and then do the move.
>
>Alternately, if you have some time to kill, do a "safe" test first.
>Create a PV/VG/LV on your new disk, get some process writing into it
>while it is mounted, and try a pvmove to another disk.  Bonus marks if
>you use something that can be verified afterwards (e.g. a tar file).
>
>"Obviously", there is only a danger at the "crossover" point of the
>tar extraction and the pvmove (i.e. only while writing to the PE that
>is being moved).  In theory, the buffers being written by tar will be
>locked when they are being written into the PE that is being moved.
>Once the pvmove is done, if e2fsck and "diff -ru" tell you that all
>is well, I think you are safe.
>
>If you are paranoid, run something really heavy like bonnie++ during the
>pvmove (only the file creation/read/deletion part) and it will complain
>if any of the files suddenly go missing or unreadable, but it doesn't
>(currently) check the file contents.  That would probably be a good
>hack - write synthetic data into each file that can easily be verified
>as correct later.
>
>Cheers, Andreas
>--
>Andreas Dilger
>http://sourceforge.net/projects/ext2resize/
>http://www-mddsp.enel.ucalgary.ca/People/adilger/
>
>
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>
>




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