Re: [ANNOUNCE] Lustre Lite 1.0 beta 1

[David Chow <davidchow@shaolinmicro.com>]

>
>
>Well, each OST is primarily (from the Lustre sense) the network interface
>protocol, and the internal implementation is opaque to the outside world.
>Each OST is independent of the others, although the clients end up allocating
>files on all of them.
>
>For Linux OSTs we use ext3 on regular block devices (raw disk, MD RAID,
>LOV, whatever you want to use) for the actual data storage, and the
>filesystem is journaled/managed totally independent from all of the
>other OSTs.  We have also used reiserfs for OST storage at times (and
>concievably you could use XFS/JFS), and there are also 3rd party vendors
>who are building OST boxes with their own non-Linux internals.
>
>Since this is just regular disk attached to regular Linux boxes, it is
>also possible to do storage server failover (already being implemented)
>without clients even being aware of a problem.  Single disk failure is
>expected to be handled by RAID of some kind.
>
>Cheers, Andreas
>  
>
Andreas,

Thanks for your lengthly explanation. The design looked like Coda with 
OST as you refer to the actual data storage. In fact, it is a stacked 
file cache or your store data in files persistently on existing file 
systesms. However, how can it handle a disconnected storage server? 
Where this is the most diffcult problem for any cluster file systems 
that support disconnection. It is obviously not allow disconnection for 
system like having thousands of nodes is bad. The chance of node failure 
is very high in those cases. As file allocation is still allowed to be 
done across multiple storage servers. The answer to resolving data 
conflicts transparently after disconnection is impossible! I would 
really like to hear this from Lustre as it already played around with 
1000 nodes. When I came down to design a distributed file system end up 
blowing my head about this. Thanks for comments or may yo give some 
directions for me as I am very interested in this topic.

regards,
David Chow