[ILUG] Using Linux to backup other os's

[Niall O Broin]

On Fri, May 11, 2001 at 09:33:40AM +0000, Andrew Kemmy wrote:

> 1./ Has anyone who might have done similar got any tips, e.g. blocksize
> to use, etc.

Use a blocksize to dd such that a block fits into an NFS block. You can set
the block sizes for an NFS mount with the rsize,wsize options. From the man
page

rsize=8192,wsize=8192
              This will make your nfs connection much faster than
              with  the  default buffer size of 1024. (NFSv2 does
              not work with larger values of rsize and wsize.) 

Mind you, I just tried this, and I was getting damn near wirespeed (copying
10M in < 1 second) when I mounted with defaults, and using
rsize=8192,wsize=8192 made no noticeable difference, but I'd use them
anyway. Better use a slightly smaller block size than that to dd, otherwise
protocol overhead will cause each dd block to become two NFS blocks which is
exactly what you're trying to avoid.

> 2./ Will dd work over NFS (is an NFS mount a block device and if not are
> there alternatives ) ?

Yes, it will. An NFS mount is seen as a block device by the OS which can
write files to it just like any other block device. As for alternatives - as
it's going to take you two hours to copy 7G if you saturate a 100baseT
connection, perhaps plugging in a spare disk temporarily might be a better
option. Of course, by the time you do that, integrate it into the OS etc.
etc. the NFS option is probably a lot simpler, and certainly will take less
of your time.

> 3./ I have a feeling the ilug BBC might be an alternative to an
> installation cd ? 

Hmm - not sure if it has support out of the box for the Smart-2 RAID. I'm
pretty sure it has support for whatever kind of smart RAID is on a DL-360,
because I've used it on a couple of those (though I ultimately built a
special CD, that was only to have the latest kernel and the latest Smart
drivers - the original did work)

> 5/  Storage medium will be cd-r. Any issues using split to create 10 650
> MB files from one 7 gig file ? 

Split should be fine, but I know I'd be checking first :-) But what OS will
your NFS server be running ? Linux up to 2.2 has a 2GB filesize limit,
though I gather this has gone in 2.4.

> Andrew Kemmy, SAIR & GNU Linux Certified Professional (and general
> dogsbody admin ;)

What's the story with SAIR certification now ? Haven't they merged their
efforts with LPI ? Where did you do the SAIR exams ?



Niall