Topic: Large backup to hard disk

[Cyrus Bharda]

I am going to ask these questions to the flexbackup help list to see wether we can get a straight answer out of them

Will report back with results!

Cyrus Bharda

[Cyrus Bharda]

And wow what a response time!

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[ Cyrus Bharda wrote: ]
> So here are our questions:
>
> 1. How big can files be created by flexbackup IF it is to a Windows NTFS share?

The limitation would be with smbfs if anything.  I have no clue what the
filesize limits are for it.  It might be your limiting factor.

> 2. Can a file that is >2GB that was created by flexbackup to a Windows
> NTFS share be restored without running into the 2GB limit on the RedHat
> Box?

If the SME core utils are from RedHat 7.x it should handle >2GB files just
fine - large file support has been around a while.

I'm not sure if the SME setup uses "buffer" or not, but buffer needs a
compilation tweak to read/write >2GB files.  If you are just using dd it
should be fine.

Basically any 2GB limits will come from the utilities used in the pipeline
- dd/buffer/dump/afio/whatever, or in the underlying filesystem (smbfs in
your case), and not from flexbackup itself.


--
 Edwin Huffstutler     Linux - because reboots are for hardware changes
 edwinh@computer.org   GnuPG Key ID: AE782DC9

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So from this basically there is no problem with flexbackup writing/reading >2GB files, right?

Cyrus Bharda

[Cyrus Bharda]

Or maybe we need to find out if there is a size limitation for smbfs and what type of pipline is used for the backup and if that has a file size limitation.

Then we will have the whole answer in its entirety.

So anyone know the answers, all I get if I google smbfs is kernal numbers which is way beyond the scope of this intermediate-noob.

Also anyone know what type of pipeline is used when SME does use flexbackup?

Thanks everyone for all the info!!

Cyrus Bharda

[Kelvin]

Hi Cyrus,

I have experimented on my old SME 5.1.2 server.

Backup to disk does not support backups > 2GB.

A quick search on google :-

smbfs does not support files > 2GB. There are patches / new versions which support up to 4GB. Still not where we want it.

And smbfs is probably not the only dependency that has limits. All in all, I think we should accept the fact that like the excellent taper program, we should only keep these for backups of small servers or servers only used for mail and gateway services (where the backups are likely to be small).

Which brings to mind a question about the 2GB limit in general. I wonder how recoverable is a large SQL database that's been split into multiple 2GB chunks ? This is the only way you can support large databases under something like the SME server <= 5.5. What if one or 2 of the database "chunks" were corrupted / damaged / accidentally - purposely deleted / etc. Will the database still be recoverable without needing a full database restore ?

Kelvin

[Nico Blok]

Hi there,

I'm following the discussion for a while. Is this what we are looking for?

http://www.cs.helsinki.fi/linux/linux-kernel/2002-22/0764.html

Greetings
Nico Blok

[Cyrus Bharda]

I don't know? All the info on that page is way over my head, might post this topic for the dev-info list and see what they think............thats if no one here can decipher the info on the page that Nico has generously supplied?

Cyrus Bharda

[Nico Blok]

I'm not sure about this, but i think that SME 5.5 is using the 2.2.? kernel. 5.6 is using the 2.4 kernel. The site i mentioned says there is no problem with kernel 2.5. For 2.4 there is a patch.
I think that there is no other way then using this patch on 2.4 (i'm not doing this, cause i dont have experience with rebuilding a kernel). Or we have to wait till an update for SME with a new kernel.

Nico Blok

[Kelvin]

It's more than just smbfs. Samba also needs updating plus you need to check the various libraries (like glibc, etc) to make sure they have LFS support, etc, etc. I'm just not sure it's worth it.

The afio utility would be a great one to use as an alternative except that it does not seem to know how to create a series of backup segment files instead of multiple instances of the same file name (which means it overwrites the previous one) and it also seems to only work interactively when doing segmented backups.

Kelvin

[Kelvin]

Oops... forgot to add ...

Of course, we all know that Darrell May already has something that works with WinRAR that does this....

Kelvin