Subject: Re: Questions regarding dump
To: Hauke Fath <hauke@Espresso.Rhein-Neckar.DE>
From: Matthew Jacob <>
List: current-users
Date: 07/21/2000 00:53:28
> Again, Matthew, can you please state your preconditions and check whether
> they are relevant in any way for the average setup where a NetBSD server
> would get used?

I'm not saying you can't use tape. I'm just pointing out the obvious to anyone
who can do simple arithmetic- direct tape storage is not adequate to cover the
available disk storage. This seems to imply to me that backup packages for
larger data sets can no longer be host based non-networked backup programs
(freeware or not).

> >You make sure your metadata is backed up offsite (this is usually still
> >a tape backup possibilty) and do mirroring and RAID stuff for the datasets and
> >hope for the best.
> What qualifies as "metadata" in this context?

Directory names, permissions, ACLs, ctime, atime.

> Seems you are happily ignoring the gap between high availability (RAID
> here) and long-term archiving (on optical storage, maybe). When you punt
> tape storage, where do you store a backup for that document someone deleted
> in error three days ago?

I'm not punting tape storage. I'm pointing out that in order to back up large
amounts of data (in the TB range) that it possibly becomes impractical to
consider dump tape sets as something to restore from.

> Mirroring and RAIDs do not protect you from human failure in any way. Your
> RAID will happily mirror your virus-infected M$ Office documents.

This is not on point to what I was talking about.

> >> I don't say it's 'all bad' as much as I say 'it does not fit my criteria of
> >> usability'.  Sorry, but with all the other free stuff out there, I don't
> >> see it as unreasonable that I should be able to back up my system for free.
> >
> >I have mixed feelings about this. On the one hand, I totally agree with you.
> >On the other hand, having spent years in the backup space, I have a sort of
> >italian-accented little subvocalized thought that keeps muttering into my
> >inner ear, "What is dis? Why do they so wanna disrespect their vital data so
> >much? It ain' right...."....
> "Why do we use NetBSD, instead of Solaris or AIX (or NT)?"
> Am I the only one who does not have TBytes of data to store (and > 5k USD
> to shell out for Legato =8> )?

Read the mails on this subject more carefully please.

Here I am- planning to try and improve via a *free* and *public* interface set
(something which actually is RFC, I believe) the less than optimal state of
affairs for a scalable (both up *AND* down) backup methodology. I don't
believe I said anything  to suggest that I'm trying to break NetBSD in favor
some large TB data storage and expensive system- sounds like your biases have
led you into a misperception here.

>Again, your "small requirements" might be average for others.

So- fine - use dump! Great! If it works for you- fine. 

> >There is nothing in my suggesting that NDMP might be useful which would
> >require any hardware changes.
> Indeed, NDMP _does_ look interesting (you might even be able to run
> Amanda's concepts over it), but it does look complex, too. In NetBSD 2.0,
> maybe... And in the meantime, _please_ let's keep dump/restore in a working
> condition!

Dump/restore *is* working for what it is. I was merely suggesting that it need
not be 'overimproved' and that effort is better spent on things like NDMP.
But, hey, like all the fixes for st.c you referred to another piece of mail
(no patches checked in I see)- go right ahead- knock yourself out...

> Amanda backs up 30+ GB of disk storage with a 4GB Tandberg SLR5 streamer
> for me. Only requirement is that partition sizes have to be below 4GB
> because level 0 dumps have to fit on one tape. But 50GB QIC drives are
> readily available,. 
>not to mention DLT or AIT drives.

Great- glad it works for you, and I'm glad you have the time to change tapes
and manage amanda to fit into tape partitions. I won't ask you to test the
NDMP implementation since clearly it's of no interest to you. Thanks for you