Hammer on-the-move

Michael Neumann mneumann at ntecs.de
Thu Jul 10 05:38:04 PDT 2008


Hi,

I think it shouldn't be too hard to switch a hammer master into a slave
and a slave to a master, isn't it?
The reason why I'd love to do that is the following:

At home, I'd like to access my files from the central file-server. This
is even much faster than doing the same via a slow laptop hard disk. The
central file-server is now the master (or the /home/mneumann pfs).
Now I want to travel around for a while and of course I don't want to go
without my home directory :)
So I mirror the central /home/mneumann to my local hard disk and switch
it (the central /home/mneumann) into a read-only slave. At the same
time, I switch the local /home/mneumann to a master and mount it
read/write. When I come back from my travel (if I come back ;-), I
mirror back the changes from local -> central and again switch the
master into a slave and vice versa.
The main advantages are:

  * You always have a backup around. You shouldn't care too much
    if your laptop gets stolen.
  * You can access your files quickly when at home (using RAID to
    accelerate) over NFS/Samba
  * Synchronization should be very fast unlike maybe rsync etc.

Btw, what would happen if I'd accidentially mount the central
file-server which right now acts as a slave read/write, modify some
files, and then mirror from the master? That is, the situation when
there are (accidentially) two masters. Will it do much harm to the file
system?
Many years ago I really hoped that what I descibed above would work out
well using the Coda File System. Then came hammer... :)
Regards,

  Michael





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