*on Monday, April 1, 2013, at 4:09 PM, Nicholas Leippe wrote:* * *
*> These below should, if supported by the device:* * * *Thanks! That's just what I was looking for!* * * *--- Dan* On Mon, Apr 1, 2013 at 4:09 PM, Nicholas Leippe <[email protected]> wrote: > On Mon, Apr 1, 2013 at 2:20 AM, Dan Egli <[email protected]> wrote: > > > > *Something that was mentioned a week or two back and I meant to follow up > > but never did was changing cache mode for Linux's disk writes. How does > one > > accomplish that and can it be done on an individual drive basis? I.e. > > Suppose I am using a set of hard disks in USB3 or eSATA enclosures to > > backup my home system. If I backup the entire raid (i.e. dd if=/dev/md0 > > of=/dev/md1) then how do I make sure that all the data was properly > written > > to the drives in md1 before I disconnect the drives and turn them off > > (since they're in enclosures I can simply turn the enclosures off)? I > don't > > want to write that way, only to assume that everything is OK and find out > > later that something didn't get written right. And yes, I know I could > > simply do an individual file backup, and that's on the agenda too. But > even > > then, unless unmounting the md1 would force all cached data to be written > > immediately anyway. But I am considering both options. So I would > > appreciate it if someone could explain to me (since I've never tried > > before) how you can go about disabling write caching to an individual > drive. > > umount # forces all data to be written > sync # also forces all data to be written > > The above two may not cause underlying block device to commit caches. > These below should, if supported by the device: > > hdparm -F > sdparm -C sync > sdparm --clear=WCE > > other options may also exist > > Also, some external enclosures interfere with reading/setting some or > all options that the underlying drive may actually provide. YMMV. > > /* > PLUG: http://plug.org, #utah on irc.freenode.net > Unsubscribe: http://plug.org/mailman/options/plug > Don't fear the penguin. > */ > /* PLUG: http://plug.org, #utah on irc.freenode.net Unsubscribe: http://plug.org/mailman/options/plug Don't fear the penguin. */
