backing up email / saving maildir on external hard drives

[Kevin Laurie]

Dear Steve,
Very valuable info. Appreciate it and will be careful when using terms.
Actually I think I should just use rsync without compressing. The reason
why I started compressing was because the GUI gave some errors when I was
trying to copy then files.

I'll just rsync the data from my laptop HDD to my external drive(without
compressing)

Thanks
Kevin

On Sunday, August 9, 2015, Steve Litt <slitt at troubleshooters.com> wrote:

> On Sat, 8 Aug 2015 10:26:55 +0530
> Kevin Laurie <superinterstellar at gmail.com <javascript:;>> wrote:
>
> > Hello,
> > Yesterday I tried to back up a 40GB maildir .
> > I tried to move the maildir from home to external HDD but failed.
>
> If you tried to *move* it it's an archive, not a backup. If you tried
> to *copy* it, with the intent of keeping the original on the original
> hard disk and using it further, and keeping today's copy on some other
> media, *that's* a backup. I'm not trying to be pedantic, but there are
> many distinctions between the two. Archives must be re-transferred
> frequently: Backups merely need to be redone at intervals.
>
> > Decided then to compress it(which took several hours). Now changing
> > the disk format from FAT to exFAT to allow the transfer for the large
> > compressed file.
>
> Reading https://en.wikipedia.org/wiki/File_Allocation_Table#exFAT , I
> personally wouldn't use exFAT. Regular FAT32 has a max filesize of
> 2GB-1, which is 50 times the size of your whole uncompressed maildir.
>
> >
> > How does one back up emails on a external drive?
> > Some advice would be greatly appreciated.
>
> Check this out:
>
> ================================================
> slitt at mydesq2:~$ df -h ~/mail/Maildir
> Filesystem      Size  Used Avail Use% Mounted on
> /dev/sdb8       116G   11G  100G  10% /home/slitt/mail/Maildir
> slitt at mydesq2:~$
> ================================================
>
> I don't have 40 GB, but * have 11, which is less than an order of
> magnitude away. I just back up this puppy to my backup server with my
> normal rsync based backup procedures, which you can read about here:
>
> * http://www.troubleshooters.com/lpm/200609/200609.htm
>
> * http://www.troubleshooters.com/linux/blu-ray-backup.htm
>
> * http://www.troubleshooters.com/lpm/201408/201408.htm
>
> The stuff about Blu-Ray is important only if you back up to blu-ray. I
> like to keep some backups on write-once media, because kept in the
> shade at reasonable temperatures and humidities, it tends to last
> longer. And spinning disks that spend the majority of their time not
> spinning tend to have problems.
>
> If this is a *backup*, I'd leave it uncompressed so you can take
> incremental backups regularly. If it's an *archive*, meaning that the
> data is immediately removed from your computer after copy, compression
> might be in order, but you should make two copies and test them both
> thoroughly before deleting the original, and you should test them every
> couple months and if either goes bad, copy the other one to something
> good. Archives are a PITA. For 40GB in these days of $150 2TB drives,
> I'd keep the data intact, back it up, and when you outgrow your hard
> drive, just get a bigger one.
>
> In other parts of this thread you ask how to separate backups from
> different accounts from different computers. As far as accounts, I
> think that Maildir directory structures would take care of that. As far
> as different machines, just put the hostname at the front of each
> destination directory.
>
>
>
> SteveT
>
> Steve Litt
> July 2015 featured book: Rapid Learning for the 21st Century
> http://www.troubleshooters.com/rl21
>