On Fri, Apr 2, 2010 at 4:55 PM, Mark Knecht <markkne...@gmail.com> wrote: > On Fri, Apr 2, 2010 at 2:49 PM, Paul Hartman > <paul.hartman+gen...@gmail.com> wrote: >> On Fri, Apr 2, 2010 at 2:50 PM, Volker Armin Hemmann >> <volkerar...@googlemail.com> wrote: >>> On Freitag 02 April 2010, Neil Bothwick wrote: >>>> On Fri, 2 Apr 2010 20:40:54 +0200, Volker Armin Hemmann wrote: >>>> > > LVM and RAID are completely different animals. No one suggested using >>>> > > it for any reasons of data security, running LVM on a RAID array >>>> > > gives both security and flexibility. As for being able to add space >>>> > > to RAID, you can't temporarily add a new volume whenever you want, >>>> > > you have to go out and buy another drive, then power down the >>>> > > computer to fit it, assuming there is room in the case for an extra >>>> > > drive. >>>> > >>>> > no need to power down - and you can add and remove drives. Read man >>>> > mdadm. >>>> >>>> Assuming your controller supports hotplugging, assuming you have a drive >>>> available to plug in, assuming you are able to physically add a drive. >>> >>> sata can hotplug. all ahci controlers can hotplug and all sata drives can >>> hotplug. If you insist on technology straight from the stone ages that is >>> your >>> problem. >> >> Do you know if it's necessary to signal to the system (like /proc/scsi >> something) that I'm about to unplug the drive, and in which order the >> power/data need to be disconnected to prevent a problem? I'm curious >> in case of future need. :) >> >> Thanks. > > If it's part of a RAID the new one gets rebuilt. > > If it's not part of a RAID then I think, as per Neil's example, the > computer is pretty much dead, right? However if you wanted to try it > (and I'm not brave enough so don't listen to me) then you might want > to do something like > > grep -A 1 dirty /proc/vmstat > > and wait until nothing is dirty. > > Just an idea,
Well, forgetting about RAID and bad drives, I should be able to unmount a normal, working SATA drive and unplug it safely, just like with a USB hard drive. I just don't know if you have to signal to SATA/AHCI that you're going to unplug (like with old hot-swappable SCSI drives), or if you need to unplug data cable before unplugging the power cable, for example.
