Re: [Evolution] Restoring Evolution

[Ralf Mardorf <silver bullet zoho com>]

On Tue, 2022-08-30 at 21:33 -0700, Mr. J wrote:
> So there's something about the process or
> the external hard drive (or both?) that prevents the creation of a
> valid .tar.gz backup file on my hard drive.  It was recently
> formatted, so I'm at a loss to explain.

Hi,

while even a brand new drive could be broken, I'm still sceptic. Drives
have got mechanisms to detect and mark bad blocks and to automagically
rewrite data. It could happen that a block was ok when writing and got
broken 10 minutes later when trying to read, this is possible, but not
much likely and it unlikely was a write error, the drive couldn't
workaround, since such a write error more or less without doubts would
have caused error messages.

On Tue, 2022-08-30 at 22:20 -0700, Mr.J wrote:
> That’s IT, I think. The external drive is formatted in FAT, and not
> exFAT. If both .tar.gz files were over 4gb, I (over) cooked my own
> goose. Talk about noobie errors.

If the file size was too large for the file system, it still doesn't
explain why there was no standard error stream and appropriate exit
status. Such an event would have caused error messages.

As already mentioned by previous mails, tar doesn't always provide error
messages when something goes wrong and the exit status could be 0, even
if an archive is corrupted, _but_ any IO error, e.g. a write error due
to a hardware issue or a violation of the size limit does cause error
messages. This is at least what I experienced.

Assuming you are using Linux, if you don't share the drive among
different operating systems, consider to format the partition/s with
ext4.

I'm usually using ext4 only and sometimes a very small FAT32 partition
for BIOS usage. To share data between Linux and iPadOS by an external
drive, I'm using hfs+. Unfortunately hfs+ isn't well supported by Linux.
Each time the drive was connected to iPadOS, I need to run fsck.hfsplus
on Linux, bevor I can more or less safely write to the drive. Very
seldom data gets lost without notification and seemingly for no reason.
"Very seldom" is still way to often for backup purpose. Whatever kind of
FAT is used, it doesn't hold UNIX-alike information used by Linux and
iPadOS. OTOH this UNIX-alike information might be irrelevant when
sharing data among Linux and iPadOS. In short, I still don't know what
file system I'll use in the future for this shared data.

For convenience I run Windows 11 as well as older Windows releases
neither on bare metal, nor as a QEMU/KVM guest or something similar, but
as a VirtualBox guest on a Linux host, hence sharing files among Linux
and Windows neither requires a special server, nor a non-Linux file
system. Unfortunately even the VirtualBox Oracle branded binaries are
often a PITA, not that much as from packages provided by distros, but
still a problem child.

Sharing data among operating systems isn't fun! It's half-baked crap and
file systems used for sharing data shouldn't be used for backups. Yes,
tar does hold UNIX-alike information inside the archive, FAT is better
supported than hfs+, but it's still not a good choice for Linux backups.

Regards,
Ralf