[ILUG] Happy ending ? (Was - Using Linux to backup other os's)

[Andrew Kemmy]

Hi All,

Niall O'Broin wrote ;

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

As it turned out, blocksize was the least of my worries !


>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

Server in question is a Proliant 1850R. I installed an ATA disk (no
spare scsi to hand) only to be told
by the Compaq BIOS that it doesn't support ATA disks ! Discovered
exactly how dusty a Proliant can get...


>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.

This was a bit of a pain. I tried using RedHat 6.2 before I recieved
Niall's reply, and, of course,
dd exited after 2 Gig. Next try was SuSE 7.0, add kernel 2.4.1 sources,
recompile, reboot.
A few errors about modules on boot but nothing serious. Unfortunately
the Kernel-based NFS server
was totally broken; "function not implemented" type errors when trying
to start NFS server.
Something I could have tried here but didn't was SUsE's patched 2.4.2
kernel.

Installed Solaris8 on the basis that the 2 Gig limit was Linux-related.
Of course dd is still running from
a SuSE 6.2 install cd. Again dd exited after 2 Gig.

Became rather hassled. Server needs to be backed up in 4 hours as others
will be installing Linux on it today and they will probably blow away
existing partitions.

# Decided to dd the disk in sections e.g. ;
dd if=/dev/ida/c0d0 of=/mnt/nfs/1184200 count=1184200 ;
dd if=/dev/ida/c0d0 of=/mnt/nfs/2368400 count=1182400 skip=1184200 ;
dd if=/dev/ida/c0d0 of=/mnt/nfs/3552600 count=1182400 skip=2368400 ;

etc etc until done.

This has the advantage of leaving me with files of cd-burning size in
/export/home0
I sincerely hope that there are no "off-by-one" errors with the above !


>> 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 ?

As far as I know SAIR and LPI are still seperate. Both sets of exams can
be taken at any
authorised Sylvan Prometric testing centre (which B.I.C. are, and so
probably are a lot of
the other commercial training centres (SureSkills, etc)). Generally we
only run exams for people
who have taken courses with us, but we do make the occasional exception
;-)



Regards,

Andrew Kemmy, A rather sleep-deprived SAIR & GNU Linux Certified
Professional.

B.I.C. Systems
7 Exchange Place
IFSC Dublin 1.

00 3531 6702900

http://www.bicsystems.com
http://www.linuxcertification.org