On Tue, 26 Dec 2017 17:20:58 -0800
Rick Moen <rick@???> wrote:

> Quoting Hendrik Boom (hendrik@???):
>
> > As I understand it, there are a few new file systems somewhat
> > available on Linux -- ZFS, XFS, and Btrfs.
> >
> > But soe are still under development, ZFS is pparently under a
> > prolematic license, and I don't know about XFS.
> >
> > I've onece heard about one of the new systems that one shouldn't
> > bother using it unless one has at least 8 gigabytes of RAM.
> >
> > Now, just how mature are these, how easily managed, how reliable.
> >
> > I'll be populating a new device with a (I hope) high-reliablity
> > file system soon. It doesn't have a lot of RAM, but the RAM does
> > have parity checking.
> >
> > Long-term data preservation is more important than speed.
> >
> > Currently on another system I'm using ext4 over LLVM over software
> > RAID-1. I know RAID isn't a reliable backup system; I make
> > separate off-line backups.
>
> Specifically, RAID isn't backup at all. It's redundancy (except for
> varieties like RAID0 that aren't even that). See: 'Backup
> Fallacies / Pitfalls' on http://linuxmafia.com/kb/Admin/
>

> > What should I be considering for the new system?  The same?    

>
> You've just asked one of the more inherently debatable questions in
> all of Linux system administration.
>
> I can only recommend that you study what the strengths and weaknesses,
> advantages and disadvantages, are of the various options at hand, and
> then design a system that implements your choices.
>
> For my own home server rebuild, I'm going with ext4, with all
> filesystems RAID1-mirrored across a pair of SSDs, and a weekly cron
> job applying TRIM. No swap (because SSDs).

Being a fan of simplicity, I use ext4 on all partitions. No LVM: I
don't want the extra layer. With things like bind mount I can
temporarily move parts of one filetree to a different partition, and
the next time I full-install or buy a new computer or something, I can
resize partitions accordingly.

ext4 is years old, proven reliable for years, has all the necess

I don't use disk encryption, but if I did I'd find a way to do it
without LVM.

I don't use RAID, and to the best of my knowledge I've never had data
silently go bad on me.

I use rsync backup from a backup server to get incrimental and full
backups at the same time via cp -al on the backup server. I back up
once or twice a week --- it should be every day. Every month or so I
copy the latest from the backup server to a couple Blu-Rays: One copy
is encrypted, the other copy is unencrypted and goes in my bank vault.

About what Hendrick asked: "Long-term data preservation is more
important than speed."

My system does almost everything Hendrick needs. The backups guard the
data, basically forever. The only issue is silent corruption. I'd
address that by a series of RAM tests and SMART tests twice a week,
just before the backup. If any new problems, look very carefully at any
changed files.

My backup scripts could be changed slightly to make some sort of
alphabetical list of all /path/filename.ext together with an md5sum, so
there could be an easy report on what changed between backups. If you
do this every day, you should get a pretty good idea whether the file
should have changed, and if not, investigate.

As somebody said, ECC RAM would certainly be helpful, but my experience
is that mobos that both accommodate ECC and run Linux are a lot more
expensive, which is fine if this is a corporate server but less so if
it's just your workstation. I'd still run a RAM check every week.

The one downfall of my method is if you absolutely, positively need
atomic backups: database files, for instance. You'd need to stop work
on the computer being backed up. In the case of my Daily Driver
Desktop, which contains 3,874,727 files, the entire backup takes about
5 minutes, the last 1.5 minutes of which is the cp -al phase, during
which the computer being backed up can go an about its business.

My system isn't for everybody, but for those wanting simplicity and
also short and long term reliability, it's pretty good.

SteveT

Steve Litt
December 2017 featured book: Thriving in Tough Times
http://www.troubleshooters.com/thrive