Re: [Xen-devel] Xen 4.3 xl migrate " htree_dirblock_to_tree" on second host

["Mike C." <miguelmclara@xxxxxxxxx>]

On February 4, 2014 11:33:42 AM GMT, Ian Campbell <Ian.Campbell@xxxxxxxxxx> 
wrote:
>On Tue, 2014-02-04 at 02:45 +0000, Miguel Clara wrote:
>> The wiki mentions "NBD" but if I got it right this means the storage
>> is in "host1" and all ndb does is connect to that host, so the disk
>is
>> never copied to disk 2?
>> 
>> Am I correct to assume this?
>
>Yes. N is for network.
>
>> I have a host where what I need is to move it from host1 to host2, or
>> reverse if needed, there's no problem stopping it first, but I guess
>> this is not what the "migrate" command is used for!
>> 
>> And for guest where I do wan to keep a backup with remus, is shared
>> storage still a must? the wiki http://wiki.xen.org/wiki/Remus states:
>> 
>> -> Shared storage is not required
>> 
>> But if "migrate" doesn't work how would remus?
>
>I think Remus with xend supports out of band storage synchronisation.
>This has not yet been implemented for xl remus support.
>

And would xl remus work if the disks are drdb 'backend' which in turn point to 
LVM?

Thanks

>> 
>> Sorry for all the questions just trying to understand this better,
>and
>> there's really no documentation about:
>> xl migrate and xl remus!
>> 
>> thanks
>> 
>> On Mon, Feb 3, 2014 at 3:09 PM, Mike C. <miguelmclara@xxxxxxxxx>
>wrote:
>> > Makes sense...
>> >
>> > Is there documentation about xl migrate and xl remus?
>> >
>> > Say I want to migrate a host but first pause it?
>> >
>> > I could also snapshot the lvm but that doesn't save the memory and
>the
>> > domain would have to be offline.
>> >
>> > So if I want to migrate but don't have shared storage, what's the
>best
>> > approach drdb?
>> >
>> > Thanks
>> >
>> >
>> >
>> > On February 3, 2014 10:17:04 AM GMT, Ian Campbell
><Ian.Campbell@xxxxxxxxxx>
>> > wrote:
>> >>
>> >> On Sat, 2014-02-01 at 01:32 +0000, Miguel Clara wrote:
>> >>>
>> >>>  I'm testing live migration without shared storage (I use LVM at
>both
>> >>> sides)
>> >>>
>> >>>
>> >>>  Issuing "xl migrate" worked nice and the machine was migrated to
>the
>> >>> second host
>> >>>
>> >>>  However I see this in the second host log:
>> >>>
>> >>>  [ 1502.563251] EXT4-fs error (device xvda1):
>> >>>  htree_dirblock_to_tree:892: inode #136303: block 533250: comm
>> >>>  run-parts: bad entry in directory: rec_len is smaller than
>minimal -
>> >>>  offset=0(0), inode=0, rec_len=0, name_len=0
>> >>>  Jan 31 17:17:01 remus-test kernel: [ 1502.563251] EXT4-fs error
>> >>>  (device xvda1): htree_dirblock_to_tree:892: inode #136303: block
>> >>>  533250: comm run-parts: bad entry in directory: rec_len is
>smaller
>> >>>  than minimal - offset=0(0), inode=0, rec_len=0, name_len=0
>> >>>
>> >>>  I also get errors
>> >>> like:
>> >>>  -bash: /bin/ping: cannot execute binary file
>> >>>
>> >>>  Is this to be expect on using none shared storage?
>> >>
>> >>
>> >> Yes. If the underlying disk is not the same device between both
>hosts
>> >> then all bets are off and all sorts of bad things will be happen.
>Think
>> >> about it -- what would you expect to happen to an OS if a disk
>suddenly
>> >> started returning completely different data to what was written to
>it.
>> >>
>> >> What you have seen seems like a plausible outcome.
>> >>
>> >> Ian.
>> >>
>> >
>> > --
>> > Sent from my Android device with K-9 Mail. Please excuse my
>brevity.

-- 
Sent from my Android device with K-9 Mail. Please excuse my brevity.

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