Re: What is the recommended armhf disk partitioner for use on rotating media?
On 17/06/17 15:45, Gene Heskett wrote:
On Saturday 17 June 2017 10:24:11 Mark Morgan Lloyd wrote:
On 17/06/17 14:15, Gene Heskett wrote:
See subject, on an rpi3b running raspian/jessie. I have a terabyte
usb drive plugged in, and I want to set up an rsync cron job to
backup the sd card to this drive and I need to reset the /dev/sda1
file system to vfat, which it is not ATM.
Use fdisk to change the type to b or c and then mkfs.vfat to reformat
it. Note however that Flash-based media might have the first partition
start at a specific block since one of the early blocks has slightly
different properties in order to accommodate frequent FAT updates, so
if you know how the device was partitioned at the factory it's worth
restoring to that if possible.
Its been re-partition with gparted, 2 or 3 times. IIRC there is a small
space, to align it or whatever in front of /dev/sda1.
fdisk has a longer and whiter beard than I do, and I wasn't aware it had
been to school to learn the new partition schemes?
There's lots of different fdisk implementations. On PC-like systems it
was originally supplied by the hardware manufacturer i.e. Zenith or
Compaq's fdisk wasn't quite the same as IBMs.
fdisk is installed and seems to recognize everything including a 2048
(sectors?) gap in front of sda1. Perhaps thats pristine yet?
plus the link bear the top.
I've spent a lot of time extracting speed info from SDCard tests over
the last couple of months, and can confirm that there /are/ differences
in the way that the first few blocks are set up. I've not yet extended
this to "stick" devices, and I don't think it's of Earth-shattering
importance for devices which are only going to be used for occasional
writes and isn't at all relevant if a device is being reformatted as
What I can say that is relevant to most people running RPis or anything
else which uses an SDCard is that with certain access patterns I was
able to get a reproducible glitch of roughly 500 mSec while the card
handled block erase etc. I suspect that it's power loss during that 500
mSec, which might extend beyond OS shutdown, that's resulted in people
suddenly finding they'd got a dud card.
So the rsync source is the sd card, and the target is this hard drive.
Does this warning still apply? I did a t[return], l[return[ but do not
see the desired vfat listed as a choice. Is it a synonym for something
apropos fsck and then look at the manpages it lists.
OTOH, one should file a bug against fdisk as the description string is
printed at a reduced width, losing valuable information about the
individual filesystem to use on a given partition.
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk
[Opinions above are the author's, not those of his employers or colleagues]