Arch Linux

darweth

Member

From: Brooklyn, NY

Registered: 2007-04-07

Posts: 68

Safe to turn external drives off w/o eject?

Hiya!  I've been using Linux for three months now, and Arch for a week.

I am curious about the need for ejecting USB external hard drives.  This is, of course, the recommended and default behavior in M$ Windows.  One is encouraged to always ejected before unplugging the USB cable or shutting down the drive.  This behavior was mirrored in Ubuntu.  I always ejected the external before turning it off.

In Arch, there is no eject.  I did install the eject function, but it does not pop up as a convenient context-menu in GNOME for usb hard drives.  Only cds.  There is the "unmount" option instead, which doesn't seem necessary.

My question is: Is it safe to just power on and off the external drive without doing any of the above?

Ramses de Norre

Member

From: Leuven - Belgium

Registered: 2007-03-27

Posts: 1,289

Re: Safe to turn external drives off w/o eject?

/usr/bin/eject is there by default, but maybe not in nautilus. I think it is still quite necessary to unmount or eject the drive, otherwise bits of data that should be on the drive could still be in memory instead. You could also run sync before pulling the drive out which should write everything to the drive but that's almost as much as a hassle as unmounting/ejecting the drive...

_alexmyself

Member

From: france

Registered: 2005-09-18

Posts: 89

Re: Safe to turn external drives off w/o eject?

yes, unmount or maybe other needed, it's stupid, 90% of data are really copy/paste but 10% stay in memory...really stupid...

elasticdog

Member

From: Washington, USA

Registered: 2005-05-02

Posts: 995

Website

Re: Safe to turn external drives off w/o eject?

I thought that as long as your mounting the drive in sync, not async, it should be fine to pull it out as long as the writes are done (the light stops blinking on the drive).  IIRC, even in Windows it is no longer necessary to actually do the whole eject process since with XP they made them mount sync by default versus the way it used to be.

byte

Member

From: Düsseldorf (DE)

Registered: 2006-05-01

Posts: 2,046

Re: Safe to turn external drives off w/o eject?

But don't use 'sync' with flash memory or dvd-ram/+rw, it will use up their limited write cycles much faster.

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1000

iphitus

Forum Fellow

From: Melbourne, Australia

Registered: 2004-10-09

Posts: 4,927

Re: Safe to turn external drives off w/o eject?

So long as it's unmounted, or all data is synced to the disk, there's no problem. Likewise on windows, if everything is written, you could easily remove it without 'safely' doing so..... but to 'safely' remove or 'unmount' is the best way to guarantee that everything is written.

James

lanrat

Member

From: Poland

Registered: 2003-10-28

Posts: 1,274

Re: Safe to turn external drives off w/o eject?

...unless you're using vfat partitions and "flush" option for mounting - it's something between sync and async. I'm using it for some time with udev automounting for usb sticks and external hd drives (with ide2usb connector). It works quite well. No problems so far. Works as fast as async but writes cache immediately (for example in mc the copying dialog stays at 100% for some time until all data is written to the disk from the cache - after the dialog is off or usb stick led stops blinking it's safe to simply unplug the device without data loss).

Last edited by lanrat (2007-04-15 14:50:24)

barebones

Member

Registered: 2006-04-30

Posts: 235

Re: Safe to turn external drives off w/o eject?

For the record, the eject command will unmount something before ejecting, so for something like a usb that doesn't actually physically eject, I beleive all you're actually doing is unmounting it.

I usually don't unmount through the right click dialog because I've noticed that gnome will remove the icon from the desktop immediately even if the drive isn't fully unmounted. This means I really don't have any way of knowing when the drive is save to remove or not. Instead, I'll use this command from the commandline:

umount /path/to/drive

That way I can know exactly when the drive is save to remove. If the mount point is in fstab, then you can do this as a user, otherwise you need root privileges.